release: 2.92.3 "Bombe glacée"

Release produced with releng/create_release.xsh

Change-Id: If52727313f7f9a0dd4ce6c95dccfeb33585eac0a

.clang-tidy

@@ -18,8 +18,6 @@ Checks:
   - -bugprone-branch-clone
     # extremely noisy before clang 19: https://github.com/llvm/llvm-project/issues/93959
   - -bugprone-multi-level-implicit-pointer-conversion
-    # we don't compile out our asserts
-  - -bugprone-assert-side-effect
     # all thrown exceptions must derive from std::exception
   - hicpp-exception-baseclass
     # capturing async lambdas are dangerous

.editorconfig

@@ -33,7 +33,3 @@ max_line_length = 0
 [meson.build]
 indent_style = space
 indent_size = 2
-
-[*.json]
-indent_style = space
-indent_size = 4

.gitignore

@@ -39,5 +39,3 @@ buildtime.bin
 
 # Python compiled files from the code generators and test suite
 *.pyc
-
-**/.idea

README.md

@@ -17,13 +17,10 @@ For systems that **already have a Nix implementation installed**, such as NixOS
 
 ## Building And Developing
 
-See our [Hacking guide](https://git.lix.systems/lix-project/lix/src/branch/main/doc/manual/src/contributing/hacking.md) in our manual for instruction on how to set up a development environment and build Lix from source.
+See our [Hacking guide](https://git.lix.systems/lix-project/lix/src/branch/main/doc/manual/src/contributing/hacking.md) in our manual for instruction on how to to set up a development environment and build Lix from source.
 
 ## Additional Resources
 
-- The Lix reference manual:
-  - [Stable](https://docs.lix.systems/manual/lix/stable/)
-  - [Nightly](https://docs.lix.systems/manual/lix/nightly/) (NOTE: [not automatically updated, yet](https://git.lix.systems/lix-project/lix/issues/742))
 - [Our wiki](https://wiki.lix.systems)
 - [Matrix - #space:lix.systems](https://matrix.to/#/#space:lix.systems)
 

bench/.gitignore

@@ -1,4 +1,3 @@
 bench-*.json
 bench-*.md
-perf-*.json
 nixpkgs

bench/bench.py

@@ -1,116 +0,0 @@
-#!/usr/bin/env nix-shell
-#!nix-shell -i python3 -p python3 -p hyperfine -p "if stdenv.isLinux then linuxPackages.perf else null"
-
-import argparse
-import subprocess
-import os
-import json
-import tempfile
-import platform
-
-flake_args = ["--extra-experimental-features","'nix-command flakes'"]
-# hyperfine has its own variable substitution, so we use that and pass build="{BUILD}" here.
-# perf doesn't have variable substitution, so we call these with build being the actual build directory.
-cases = {
-    "search": lambda build: [f"{build}/bin/nix", *flake_args, "search", "--no-eval-cache", "github:nixos/nixpkgs/e1fa12d4f6c6fe19ccb59cac54b5b3f25e160870", "hello"],
-    "rebuild": lambda build: [f"{build}/bin/nix", *flake_args, "eval", "--raw", "--impure", "--expr", "'with import <nixpkgs/nixos> {}; system'"],
-    "rebuild_lh": lambda build: ["GC_INITIAL_HEAP_SIZE=10g", f"{build}/bin/nix", *flake_args, "eval", "--raw", "--impure", "--expr", "'with import <nixpkgs/nixos> {}; system'"],
-    "parse": lambda build: [f"{build}/bin/nix", *flake_args, "eval", "-f", "bench/nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix"],
-}
-
-arg_parser = argparse.ArgumentParser()
-# FIXME(jade, gilice): it is a reasonable use case to want to run a benchmark run
-# on just one build. However, since we are using hyperfine in comparison
-# mode, we would have to combine the JSON ourselves to support that, which
-# would probably be better done by writing a benchmarking script in
-# not-bash.
-arg_parser.add_argument('builds', nargs='+', help="At least two build directories to compare, containing bin/nix")
-arg_parser.add_argument('--cases', type=str, help="A comma-separated list of cases you want to run. Defaults to running all")
-available_modes = [ "walltime" ] + [ "icount" ] if platform.system() == 'Linux' else [] # perf doesn't run on Darwin
-arg_parser.add_argument('--mode', choices=available_modes, default="walltime")
-args = arg_parser.parse_args()
-if len(args.builds) < 2:
-    raise ValueError("need at least two build directories to compare")
-
-benchmarks: list[str] = []
-if args.cases is None:
-    benchmarks = list(cases.keys())
-else:
-    for case in args.cases.split(","):
-        if case not in cases: raise ValueError(f"no such case: {case}")
-        benchmarks.append(case)
-
-def bench_walltime(env):
-    hyperfine_args = ["--parameter-list", "BUILD", ','.join(args.builds), "--warmup", "2", "--runs", "10"]
-    for case in benchmarks:
-        case_command = cases[case]("{BUILD}") # see the comment on cases
-        subprocess.run([
-            "taskset", "-c", "2,3",
-            "chrt", "-f","50",
-            "hyperfine", *hyperfine_args, "--export-json", f"bench/bench-{case}.json", "--export-markdown", f"bench/bench-{case}.md", "--", " ".join(case_command)
-        ], env=env, check=True)
-
-    print("Benchmarks summary\n---\n")
-    for case in benchmarks:
-        fd = open(f"bench/bench-{case}.json")
-        result_json = json.load(fd)
-        fd.close()
-        for result in result_json["results"]:
-            print(result["command"])
-            print("-" * min(80,len(result["command"])))
-            attr_rounded = lambda attr: f"{result[attr]:.3f}"
-            print("  mean:    ", attr_rounded("mean"), "±", attr_rounded("stddev"))
-            print("            user:",  attr_rounded("user"), "| system", attr_rounded("system"))
-            print("  median:  ", attr_rounded("median"))
-            print("  range:   ", attr_rounded("min") + "s.." + attr_rounded("max")+"s")
-            print("  relative:", f"{result["mean"]/result_json["results"][0]["mean"]:.3f}")
-            print("\n")
-
-
-def bench_icount(env):
-    perf_results_for: dict[str, list[tuple[str, float]]] = {}
-    for case in benchmarks:
-        for build in args.builds:
-            case_command = cases[case](build)
-            # the perf stat -j output (incorrectly) localizes numbers, which will trip up the json parser.
-            env["LC_ALL"]="C"
-            commandline = [
-                "perf", "stat", "-o", f"bench/perf-{case}.json", "-j", "sh", "-c", " ".join(case_command)
-            ]
-            subprocess.run(commandline, env=env, check=True, stdout=subprocess.DEVNULL) # warmup run
-            subprocess.run(commandline, env=env, check=True, stdout=subprocess.DEVNULL)
-            perf_fd = open(f"bench/perf-{case}.json")
-            perf_data = [json.loads(x) for x in perf_fd.readlines()]
-            perf_fd.close()
-
-            instr = next(x for x in perf_data if x["event"] in ["instructions", "instructions:u"]) # an implementation of a find_first iterator
-            if case not in perf_results_for: perf_results_for[case] = []
-            perf_results_for[case].append((" ".join(case_command), float(instr["counter-value"])))
-
-    print("Benchmarks summary\n---\n")
-    for (case, entries) in perf_results_for.items():
-        for entry in entries:
-            cmd,instr = entry
-            print(cmd)
-            print("-" * min(80,len(cmd)))
-            print("  instructions:         ", int(instr))
-            print("  relative instructions:", int(instr)/perf_results_for[case][0][1])
-            print("\n")
-
-
-with tempfile.TemporaryDirectory() as tmp_dir:
-    subprocess.run([
-        "nix", "build",
-        "--extra-experimental-features", "nix-command flakes",
-        "--impure", "--expr",'(builtins.getFlake "git+file:.").inputs.nixpkgs.outPath',
-        "-o","bench/nixpkgs"
-    ], check=True)
-    subenv = os.environ.copy()
-    subenv["NIX_CONF_DIR"] = "/var/empty"
-    subenv["NIX_REMOTE"] = tmp_dir
-    subenv["NIX_PATH"] = "nixpkgs=bench/nixpkgs:nixos-config=bench/configuration.nix"
-
-    if args.mode == "walltime":
-        bench_walltime(subenv)
-    else:
-        bench_icount(subenv)

bench/bench.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p bash -p hyperfine
+
+set -euo pipefail
+shopt -s inherit_errexit
+
+scriptdir=$(cd "$(dirname -- "$0")" ; pwd -P)
+cd "$scriptdir/.."
+
+if [[ $# -lt 2 ]]; then
+    # FIXME(jade): it is a reasonable use case to want to run a benchmark run
+    # on just one build. However, since we are using hyperfine in comparison
+    # mode, we would have to combine the JSON ourselves to support that, which
+    # would probably be better done by writing a benchmarking script in
+    # not-bash.
+    echo "Fewer than two result dirs given, nothing to compare!" >&2
+    echo "Pass some directories (with names indicating which alternative they are) with bin/nix in them" >&2
+    echo "Usage: ./bench/bench.sh result-1 result-2 [result-3...]" >&2
+    exit 1
+fi
+
+_exit=""
+trap "$_exit" EXIT
+
+flake_args=("--extra-experimental-features" "nix-command flakes")
+
+# XXX: yes this is very silly. flakes~!!
+nix build "${flake_args[@]}" --impure --expr '(builtins.getFlake "git+file:.").inputs.nixpkgs.outPath' -o bench/nixpkgs
+
+# We must ignore the global config, or else NIX_PATH won't work reliably.
+# See https://github.com/NixOS/nix/issues/9574
+export NIX_CONF_DIR='/var/empty'
+export NIX_REMOTE="$(mktemp -d)"
+_exit='rm -rfv "$NIX_REMOTE"; $_exit'
+export NIX_PATH="nixpkgs=bench/nixpkgs:nixos-config=bench/configuration.nix"
+
+builds=("$@")
+
+flake_args="${flake_args[*]@Q}"
+
+hyperfineArgs=(
+    --parameter-list BUILD "$(IFS=,; echo "${builds[*]}")"
+    --warmup 2 --runs 10
+)
+
+declare -A cases
+cases=(
+    [search]="{BUILD}/bin/nix $flake_args search --no-eval-cache github:nixos/nixpkgs/e1fa12d4f6c6fe19ccb59cac54b5b3f25e160870 hello"
+    [rebuild]="{BUILD}/bin/nix $flake_args eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'"
+    [rebuild-lh]="GC_INITIAL_HEAP_SIZE=10g {BUILD}/bin/nix eval $flake_args --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'"
+    [parse]="{BUILD}/bin/nix $flake_args eval -f bench/nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix"
+)
+
+benches=(
+    rebuild
+    rebuild-lh
+    search
+    parse
+)
+
+for k in "${benches[@]}"; do
+    taskset -c 2,3 \
+        chrt -f 50 \
+        hyperfine "${hyperfineArgs[@]}"  --export-json="bench/bench-${k}.json" --export-markdown="bench/bench-${k}.md" "${cases[$k]}"
+done
+
+echo "Benchmarks summary (from ./bench/summarize.jq bench/bench-*.json)"
+bench/summarize.jq bench/*.json

bench/summarize.jq

@@ -0,0 +1,22 @@
+#!/usr/bin/env -S jq -Mrf
+
+def round3:
+    . * 1000 | round | . / 1000
+    ;
+
+def stats($first):
+    [
+        "  mean:     \(.mean | round3)s ± \(.stddev | round3)s",
+        "            user: \(.user | round3)s | system: \(.system | round3)s",
+        "  median:   \(.median | round3)s",
+        "  range:    \(.min | round3)s ... \(.max | round3)s",
+        "  relative: \(.mean / $first.mean | round3)"
+    ]
+    | join("\n")
+    ;
+
+def fmt($first):
+    "\(.command)\n" + (. | stats($first))
+    ;
+
+[.results | .[0] as $first | .[] | fmt($first)] | join("\n\n") | (. + "\n\n---\n")

doc/manual/book.toml

@@ -7,8 +7,9 @@ create-missing = false
 [output.html]
 additional-css = ["custom.css"]
 additional-js = ["redirects.js"]
-# Jumps directly into a new Gerrit CL editing the file in question.
-edit-url-template = "https://gerrit.lix.systems/admin/repos/edit/repo/lix/branch/main/file/doc/manual/{path}"
+# Using our GitHub mirror enables easier typo fixes since there is no easy way
+# to just submit a Gerrit CL by the web for trivial stuff.
+edit-url-template = "https://github.com/lix-project/lix/tree/main/doc/manual/{path}"
 git-repository-url = "https://git.lix.systems/lix-project/lix"
 # Folding by default would prevent things like "Ctrl+F for nix-env" from working
 # trivially, but the user should be able to fold if they want to.

doc/manual/change-authors.yml

@@ -12,10 +12,6 @@
   forgejo: rbt
   github: 9999years
 
-9p4:
-  display_name: Ersei Saggi
-  github: 9p4
-
 Artturin:
   github: Artturin
 
@@ -40,10 +36,6 @@ alois31:
   forgejo: alois31
   github: alois31
 
-andrewhamon:
-  display_name: Andrew Hamon
-  github: andrewhamon
-
 artemist:
   display_name: Artemis Tosini
   forgejo: artemist
@@ -53,10 +45,6 @@ bb010g:
   forgejo: bb010g
   github: bb010g
 
-blitz:
-  display_name: Julian Stecklina
-  github: blitz
-
 cole-h:
   display_name: Cole Helbling
   github: cole-h
@@ -66,13 +54,6 @@ delan:
   forgejo: delan
   github: delan
 
-delroth:
-  github: delroth
-
-detroyejr:
-  display_name: Jonathan De Troye
-  github: detroyejr
-
 edolstra:
   display_name: Eelco Dolstra
   github: edolstra
@@ -112,11 +93,6 @@ jade:
 just1602:
   forgejo: just1602
 
-kfears:
-  display_name: KFears
-  forgejo: kfearsoff
-  github: kfearsoff
-
 kiara:
   github: KiaraGrouwstra
 
@@ -132,10 +108,6 @@ lheckemann:
   forgejo: lheckemann
   github: lheckemann
 
-lily:
-  forgejo: lilyinstarlight
-  github: lilyinstarlight
-
 lilyball:
   forgejo: lilyball
   github: lilyball
@@ -158,32 +130,16 @@ midnightveil:
 ncfavier:
   github: ncfavier
 
-p-e-meunier:
-  display_name: Pierre-Etienne Meunier
-  github: P-E-Meunier
-
-pamplemousse:
-  display_name: Xavier Maso
-  github: pamplemousse
-
 piegames:
   display_name: piegames
   forgejo: piegames
   github: piegamesde
 
-poliorcetics:
-  display_name: Poliorcetics
-  github: poliorcetics
-
 puck:
   display_name: puck
   forgejo: puck
   github: puckipedia
 
-quantenzitrone:
-  display_name: Zitrone
-  forgejo: quantenzitrone
-
 quantumjump:
   display_name: Quantum Jump
   github: QuantumBJump
@@ -200,18 +156,6 @@ roberth:
   display_name: Robert Hensing
   github: roberth
 
-seppel3210:
-  github: Seppel3210
-
-teofilc:
-  forgejo: teofilc
-  github: TeofilC
-
-thubrecht:
-  display_name: Tom Hubrecht
-  forgejo: tom-hubrecht
-  github: Tom-Hubrecht
-
 thufschmitt:
   display_name: Théophane Hufschmitt
   github: thufschmitt
@@ -233,12 +177,6 @@ winter:
   forgejo: winter
   github: winterqt
 
-xanderio:
-  github: xanderio
-
-yorickvp:
-  github: yorickvp
-
 yshui:
   github: yshui
 

doc/manual/meson.build

@@ -1,7 +1,6 @@
 nix_env_for_docs = {
   'HOME': '/dummy',
   'NIX_CONF_DIR': '/dummy',
-  'XDG_CONFIG_HOME': '/dummy',
   'NIX_SSL_CERT_FILE': '/dummy/no-ca-bundle.crt',
   'NIX_STATE_DIR': '/dummy',
   'NIX_CONFIG': 'cores = 0',

doc/manual/rl-next/deprecated-derivation-types.md

@@ -1,16 +0,0 @@
----
-synopsis: Deprecation of CA derivations, dynamic derivations, and impure derivations
-issues: [fj#815]
-cls: []
-significance: significant
-category: Miscellany
-credits: []
----
-
-Content-addressed derivations are now deprecated and slated for removal in Lix 2.94.
-We're doing this because the CA derivation system has been a known cause of problems
-and inconsistencies, is unmaintained, habitually makes improving the store code very
-difficult (or blocks such improvements outright), and is beset by a number of design
-flaws that in our opinion cannot be fixed without a full reimplementation from zero.
-Dynamic derivations and impure derivations are built on the CA derivation framework,
-and owing to this they too are deprecated and slated for removal in another release.

doc/manual/rl-next/integer-coercion.md

@@ -1,47 +0,0 @@
----
-synopsis: Experimental integer coercion in interpolated strings
-issues: []
-cls: [3198]
-category: "Features"
-credits: [raito, delroth, horrors, winter]
----
-
-Ever tried interpolating a port number in Lix and ended up with something like this?
-
-```nix
-"http://${config.network.host}:${builtins.toString config.network.port}/"
-```
-
-You're not alone. Thousands of Lix users suffer every day from excessive `builtins.toString` syndrome. It’s 2025, and we still have to cast integers to use them in strings.
-
-To address this, Lix introduces the **`coerce-integers`** experimental feature. When enabled, interpolated integers within `"${...}"` are automatically coerced to strings. This allows writing:
-
-```nix
-"http://${config.network.host}:${config.network.port}/"
-```
-
-without additional conversion.
-
-To enable the feature, you need to add `coerce-integers` to your set of experimental features.
-
-### Stabilization criteria
-
-The `coerce-integers` feature is experimental and limited strictly to string interpolation (`"${...}"`). Before stabilization, the following must hold:
-
-1. **Interpolation-only**
-   Coercion must not occur outside interpolation. Expressions like `"" + 42` must continue to fail.
-
-2. **Expectation that no explicit cast are being observed**
-   Cases observing explicit coercion (e.g., via `tryEval` gadget or similar) are expected not to be load-bearing in actual production code.
-
-### Timeline for stabilization
-
-If the feature proves safe and is widely adopted across typical usage (e.g., actual configurations in the wild turning on the flag, non-trivial out-of-tree projects using it), the experimental flag will be removed **after six months of active use or two Lix releases**, whichever is longer.
-
-This avoids locking the feature in experimental status indefinitely, as happened with Flakes, while allowing time for validation and ecosystem integration.
-
-### What about coercing floats or more?
-
-Coercion beyond integers -- such as for floats or other types -- is **not planned**, even under an experimental flag. Questions like "what is the canonical string representation of a float?" involve subtle and context-dependent trade-offs. Without a robust and principled mechanism to define and audit such behavior, introducing broader coercion risks setting unintended and hard-to-reverse precedents. The scope of `coerce-integers` is intentionally narrow and will remain so.
-
-In terms of outlook, a proposal like https://git.lix.systems/lix-project/lix/issues/835 could pave the way for a better solution.

doc/manual/rl-next/log-output-terminal-codes.md

@@ -1,11 +0,0 @@
----
-synopsis: Fix handling of OSC codes in terminal output
-issues: [fj#160]
-cls: [3143]
-category: Fixes
-credits: [lilyball]
----
-
-OSC codes in terminal output are now handled correctly, where OSC 8 (hyperlink) is preserved any
-time color codes are allowed and all other OSC codes are stripped out. This applies not only to
-output from build commands but also to rendered documentation in the REPL.

doc/manual/rl-next/mismatch-check-path.md

@@ -1,14 +0,0 @@
----
-synopsis: Better debuggability on fixed-output hash mismatches
-issues: []
-cls: []
-category: Improvements
-credits: [lheckemann]
----
-
-Fixed-output derivation hash mismatch error messages will now include the path that was
-produced unexpectedly, and this path will be registered as valid even if `--check`
-(`nix-store`, `nix-build`) or `--rebuild` (`nix build`) was passed. This makes comparing
-the expected path with the obtained path easier, and is useful for debugging when
-upstreams modify previously-published releases or when changes in fixed-output
-derivations' dependencies affect their output unexpectedly.

doc/manual/rl-next/reliance-on-bash-for-ssh.md

@@ -1,21 +0,0 @@
----
-synopsis: Remove reliance on Bash for remote stores via SSH
-issues: [fj#830, fj#805, fj#304]
-cls: [3159]
-category: "Fixes"
-credits: [raito]
----
-
-The pre-flight `echo started` handshake -- added years ago to catch race conditions -- has been removed.
-
-After removal of connection sharing in Lix 2.93, it required a Bash-compatible shell and a standard `echo`, so it failed on:
-
-  * builders protected by `ForceCommand` wrappers (e.g. `nix-remote-build`),
-  * BusyBox / initrd images with no Bash,
-  * hosts using non-POSIX shells such as Nushell.
-
-The race the probe once addressed was tied to SSH connection-sharing -- since connection-sharing code has already been removed, the probe is now pointless.
-
-Real connection or protocol errors are now left to SSH/Nix to report directly.
-
-This is technically a breaking change if you had scripts that relied on the literal "started" which needs to be updated to rely on other signals, e.g., exit codes.

doc/manual/rl-next/remove-xp-derivations.md

@@ -1,17 +0,0 @@
----
-synopsis: Remove impure derivations and dynamic derivations
-issues: [fj#815]
-cls: [3210]
-significance: significant
-category: "Breaking Changes"
-credits: [horrors]
----
-
-The `impure-derivations` and `dynamic-derivations` experimental feature have
-been removed.
-
-New impure or dynamic derivations cannot be created from this point forward, and
-any such pre-existing store derivations canot be read or built any more.
-Derivation outputs created by building such a derivation are still valid
-until garbage collected; existing store derivations can only be garbage
-collected.

doc/manual/src/SUMMARY.md

@@ -20,6 +20,7 @@
   - [Basic Package Management](package-management/basic-package-mgmt.md)
   - [Profiles](package-management/profiles.md)
   - [Garbage Collection](package-management/garbage-collection.md)
+    - [Garbage Collector Roots](package-management/garbage-collector-roots.md)
   - [Sharing Packages Between Machines](package-management/sharing-packages.md)
     - [Serving a Nix store via HTTP](package-management/binary-cache-substituter.md)
     - [Copying Closures via SSH](package-management/copy-closure.md)
@@ -197,7 +198,6 @@
 - [Release Notes](release-notes/release-notes.md)
   - [Upcoming release](release-notes/rl-next.md)
     <!-- RELENG-AUTO-INSERTION-MARKER (see releng/release_notes.py) -->
-  - [Lix 2.93 (2025-05-09)](release-notes/rl-2.93.md)
   - [Lix 2.92 (2025-01-18)](release-notes/rl-2.92.md)
   - [Lix 2.91 (2024-08-12)](release-notes/rl-2.91.md)
   - [Lix 2.90 (2024-07-10)](release-notes/rl-2.90.md)

doc/manual/src/advanced-topics/distributed-builds.md

@@ -75,9 +75,7 @@ by spaces. Only the first element is required. To leave a field at its
 default, set it to `-`.
 
 1.  The URI of the remote store in the format
-    `ssh://[username@]hostname[?port=<port>]`, e.g. `ssh://nix@mac` or `ssh://mac`.
-    If the ssh server is not listening on port 22 (e.g. port 1337 in this case)
-    the URI would be `ssh://nix@mac?port=1337`
+    `ssh://[username@]hostname`, e.g. `ssh://nix@mac` or `ssh://mac`.
     For backward compatibility, `ssh://` may be omitted. The hostname
     may be an alias defined in your `~/.ssh/config`.
 

doc/manual/src/architecture/architecture.md

@@ -22,9 +22,9 @@ The following [concept map] shows its main components (rectangles), the objects
            |                   |
 +----------|-------------------|--------------------------------+
 | Nix impl.|                   V                                |
-| (Lix)    |       +------------------------+                   |
-|          |       | command line interface |------.            |
-|          |       +------------------------+      |            |
+| (Lix)    |      +-------------------------+                   |
+|          |      | commmand line interface |------.            |
+|          |      +-------------------------+      |            |
 |          |                   |                   |            |
 |    evaluated by            calls              manages         |
 |          |                   |                   |            |

doc/manual/src/command-ref/fileish-summary.md

@@ -1,12 +0,0 @@
-<!--
-  File-ish argument syntax summary.
-  This file gets included into pages like nix-build.md and nix-instantiate.md, and each individual page that includes
-  this also links to nix-build.md for the full explanation.
--->
-- A normal filesystem path, like `/home/meow/nixfiles/default.nix`
-  - Or a directory, like `/home/meow/nixfiles`, equivalent to above
-- A single lookup path, like `<nixpkgs>` or `<nixos>`
-- A URL to a tarball, like `https://github.com/NixOS/nixpkgs/archive/refs/heads/release-23.11.tar.gz`
-- A [flakeref](@docroot@/command-ref/new-cli/nix3-flake.md#flake-references), introduced by the prefix `flake:`, like `flake:git+https://git.lix.systems/lix-project/lix`
-- A *nixpkgs* channel tarball name, introduced by the prefix `channel:`, like `channel:nixos-unstable`.
-  - This uses a hard-coded URL pattern and is *not* related to the subscribed channels managed by the [nix-channel](@docroot@/command-ref/nix-channel.md) command.

doc/manual/src/command-ref/nix-build.md

@@ -4,7 +4,7 @@
 
 # Synopsis
 
-`nix-build` [*fileish…*]
+`nix-build` [*paths…*]
   [`--arg` *name* *value*]
   [`--argstr` *name* *value*]
   [{`--attr` | `-A`} *attrPath*]
@@ -20,55 +20,19 @@ For documentation on the latter, run `nix build --help` or see `man nix3-build`.
 # Description
 
 The `nix-build` command builds the derivations described by the Nix
-expressions in each *fileish*. If the build succeeds, it places a symlink to
+expressions in *paths*. If the build succeeds, it places a symlink to
 the result in the current directory. The symlink is called `result`. If
 there are multiple Nix expressions, or the Nix expressions evaluate to
 multiple derivations, multiple sequentially numbered symlinks are
 created (`result`, `result-2`, and so on).
 
-If no *fileish* is specified, then `nix-build` will use `default.nix` in
+If no *paths* are specified, then `nix-build` will use `default.nix` in
 the current directory, if it exists.
 
-## Fileish Syntax
-
-A given *fileish* may take one of a few different forms, the first being a simple filesystem path, e.g. `nix-build /tmp/some-file.nix`.
-Like the [import builtin](../language/builtins.md#builtins-import) specifying a directory is equivalent to specifying `default.nix` within that directory.
-It may also be a [search path](./env-common.md#env-NIX_PATH) (also known as a lookup path) like `<nixpkgs>`, which is convenient to use with `--attr`/`-A`:
-
-```console
-$ nix-build '<nixpkgs>' -A firefox
-```
-
-(Note the quotation marks around `<nixpkgs>`, which will be necessary in most Unix shells.)
-
-If a *fileish* starts with `http://` or `https://`, it is interpreted as the URL of a tarball which will be fetched and unpacked.
-Lix will then `import` the unpacked directory, so these tarballs must include at least a single top-level directory with a file called `default.nix`
-For example, you could build from a specific version of Nixpkgs with something like:
-
-```console
-$ nix-build "https://github.com/NixOS/nixpkgs/archive/refs/heads/release-23.11.tar.gz" -A firefox
-```
-
-If a path starts with `flake:`, the rest of the argument is interpreted as a [flakeref](./new-cli/nix3-flake.md#flake-references) (see `nix flake --help` or `man nix3-flake`), which requires the "flakes" experimental feature to be enabled.
-Lix will fetch the flake, and then `import` its unpacked directory, so the flake must include a file called `default.nix`.
-For example, the flake analogues to the above `nix-build` commands are:
-
-```console
-$ nix-build flake:nixpkgs -A firefox
-$ nix-build flake:github:NixOS/nixpkgs/release-23.11 -A firefox
-```
-
-Finally, for legacy reasons, if a path starts with `channel:`, the rest of the argument is interpreted as the name of a *nixpkgs* channel tarball to fetch from `https://nixos.org/channels/$CHANNEL_NAME/nixexprs.tar.xz`.
-This is a **hard coded URL** pattern and is *not* related to the subscribed channels managed by the [nix-channel](./nix-channel.md) command.
-
-> **Note**: any of the special syntaxes may always be disambiguated by prefixing the path.
-> For example: a file in the current directory literally called `<nixpkgs>` can be addressed as `./<nixpkgs>`, to escape the special interpretation.
-
-In summary, a path argument may be one of:
-
-{{#include ./fileish-summary.md}}
-
-## Notes
+If an element of *paths* starts with `http://` or `https://`, it is
+interpreted as the URL of a tarball that will be downloaded and unpacked
+to a temporary location. The tarball must include a single top-level
+directory containing at least a file named `default.nix`.
 
 `nix-build` is essentially a wrapper around
 [`nix-instantiate`](nix-instantiate.md) (to translate a high-level Nix

doc/manual/src/command-ref/nix-channel.md

@@ -14,7 +14,7 @@ The moving parts of channels are:
 - The official channels listed at <https://nixos.org/channels>
 - The user-specific list of [subscribed channels](#subscribed-channels)
 - The [downloaded channel contents](#channels)
-- The [Nix expression search path](@docroot@/command-ref/conf-file.md#conf-nix-path), set with the [`-I` option](#opt-I) or the [`NIX_PATH` environment variable](#env-NIX_PATH)
+- The [Nix expression search path](@docroot@/command-ref/conf-file.md#conf-nix-path), set with the [`-I` option](#opt-i) or the [`NIX_PATH` environment variable](#env-NIX_PATH)
 
 > **Note**
 >

doc/manual/src/command-ref/nix-collect-garbage.md

@@ -36,7 +36,7 @@ Instead, it looks in a few locations, and acts on all profiles it finds there:
    >
    > Not stable; subject to change
    >
-   > Do not rely on this functionality; it just exists for migration purposes and may change in the future.
+   > Do not rely on this functionality; it just exists for migration purposes and is may change in the future.
    > These deprecated paths remain a private implementation detail of Lix.
 
    <!-- FIXME(Qyriad): this is inconsistent with https://git.lix.systems/lix-project/lix/issues/215, needs updating when that happens -->

doc/manual/src/command-ref/nix-env.md

@@ -8,7 +8,7 @@
   [`--option` *name* *value*]
   [`--arg` *name* *value*]
   [`--argstr` *name* *value*]
-  [{`--file` | `-f`} *fileish*]
+  [{`--file` | `-f`} *path*]
   [{`--profile` | `-p`} *path*]
   [`--system-filter` *system*]
   [`--dry-run`]

doc/manual/src/command-ref/nix-env/delete-generations.md

@@ -26,7 +26,7 @@ This operation deletes the specified generations of the current profile.
   >
   > Older *and newer* generations will be deleted by this operation.
   >
-  > One might expect this to just delete older generations than the current one, but that is only true if the current generation is also the latest.
+  > One might expect this to just delete older generations than the curent one, but that is only true if the current generation is also the latest.
   > Because one can roll back to a previous generation, it is possible to have generations newer than the current one.
   > They will also be deleted.
 

doc/manual/src/command-ref/nix-env/install.md

@@ -11,7 +11,6 @@
   [`--from-profile` *path*]
   [`--preserve-installed` | `-P`]
   [`--remove-all` | `-r`]
-  [`--priority` *priority*]
 
 # Description
 
@@ -60,11 +59,6 @@ a number of possible ways:
     unambiguous way, which is necessary if there are multiple
     derivations with the same name.
 
-  - If `--priority` *priority* is given, the priority of the derivations being
-    installed is set to *priority*. This can be used to override the priority of
-    the derivations being installed. This is useful if *args* are store paths,
-    which don't have any priority information.
-
   - If *args* are [store derivations](@docroot@/glossary.md#gloss-store-derivation), then these are
     [realised](@docroot@/command-ref/nix-store/realise.md), and the resulting output paths
     are installed.

doc/manual/src/command-ref/nix-env/opt-common.md

@@ -2,16 +2,16 @@
 
 The following options are allowed for all `nix-env` operations, but may not always have an effect.
 
-  - `--file` / `-f` *fileish*\
+  - `--file` / `-f` *path*\
     Specifies the Nix expression (designated below as the *active Nix
     expression*) used by the `--install`, `--upgrade`, and `--query
     --available` operations to obtain derivations. The default is
     `~/.nix-defexpr`.
 
-    *fileish* is interpreted the same as with [nix-build](../nix-build.md#fileish-syntax).
-    See that section for complete details (`nix-build --help`), but in summary, a path argument may be one of:
-
-    {{#include ../fileish-summary.md}}
+    If the argument starts with `http://` or `https://`, it is
+    interpreted as the URL of a tarball that will be downloaded and
+    unpacked to a temporary location. The tarball must include a single
+    top-level directory containing at least a file named `default.nix`.
 
   - `--profile` / `-p` *path*\
     Specifies the profile to be used by those operations that operate on

doc/manual/src/command-ref/nix-env/upgrade.md

@@ -22,7 +22,7 @@ left untouched; this is not an error. It is also not an error if an
 element of *args* matches no installed derivations.
 
 For a description of how *args* is mapped to a set of store paths, see
-[`--install`](install.md). If *args* describes multiple
+[`--install`](#operation---install). If *args* describes multiple
 store paths with the same symbolic name, only the one with the highest
 version is installed.
 

doc/manual/src/command-ref/nix-instantiate.md

@@ -11,7 +11,7 @@
   [{`--attr`| `-A`} *attrPath*]
   [`--add-root` *path*]
   [`--expr` | `-E`]
-  *fileish…*
+  *files…*
 
 `nix-instantiate` `--find-file` *files…*
 
@@ -25,11 +25,8 @@ of the resulting store derivations are printed on standard output.
 
 [store derivation]: ../glossary.md#gloss-store-derivation
 
-If *fileish* is the character `-`, then a Nix expression will be read from standard input.
-Otherwise, each *fileish* is interpreted the same as with [nix-build](./nix-build.md#fileish-syntax).
-See that section for complete details (`nix-build --help`), but in summary, a path argument may be one of:
-
-{{#include ./fileish-summary.md}}
+If *files* is the character `-`, then a Nix expression will be read from
+standard input.
 
 # Options
 
@@ -38,14 +35,7 @@ See that section for complete details (`nix-build --help`), but in summary, a pa
 
   - `--parse`\
     Just parse the input files, and print their abstract syntax trees on
-    standard output. The output format of the AST depends on the current
-    internal representation and may change in the future.
-
-    Tooling can use the stderr and exit code of `--parse` to check any
-    Nix code for correctness, but should not rely on stdout without careful
-    versioning. Note that `--parse` also checks for unbound variables.
-    In cases where this is undesired, `with {};` can be prepended
-    to the program to transform all such parse errors into eval errors.
+    standard output as a Nix expression.
 
   - `--eval`\
     Just parse and evaluate the input files, and print the resulting

doc/manual/src/command-ref/nix-shell.md

@@ -33,9 +33,10 @@ the environment of a derivation for development.
 If *path* is not given, `nix-shell` defaults to `shell.nix` if it
 exists, and `default.nix` otherwise.
 
-If *path* is given it is interpreted like a [*fileish* argument to nix-build](./nix-build.md#fileish-syntax):
-
-{{#include ./fileish-summary.md}}
+If *path* starts with `http://` or `https://`, it is interpreted as the
+URL of a tarball that will be downloaded and unpacked to a temporary
+location. The tarball must include a single top-level directory
+containing at least a file named `default.nix`.
 
 If the derivation defines the variable `shellHook`, it will be run
 after `$stdenv/setup` has been sourced. Since this hook is not executed

doc/manual/src/command-ref/nix-store/delete.md

@@ -4,7 +4,7 @@
 
 # Synopsis
 
-`nix-store` `--delete` [`--ignore-liveness`] [`--skip-live`] [`--delete-closure`] *paths…*
+`nix-store` `--delete` [`--ignore-liveness`] *paths…*
 
 # Description
 
@@ -18,13 +18,6 @@ With the option `--ignore-liveness`, reachability from the roots is
 ignored. However, the path still won’t be deleted if there are other
 paths in the store that refer to it (i.e., depend on it).
 
-This operation will raise an error if any of the paths are still live
-and `--ignore-liveness` is not passed. Passing `--skip-live` will
-prevent this from being considered an error.
-
-The option `--delete-closure` will also attempt to delete any paths
-that are in the given path's dependency closure.
-
 {{#include ./opt-common.md}}
 
 {{#include ../opt-common.md}}

doc/manual/src/command-ref/nix-store/query.md

@@ -93,12 +93,9 @@ symlink.
     [deriver]: ../../glossary.md#gloss-deriver
 
   - `--valid-derivers`\
-    Prints the set of all [derivers](../../glossary.md#gloss-deriver) that can be
-    used to build the store paths *paths*.
-    This differs from `--deriver`, which prints the deriver that actually
-    produced *paths*.
-    No deriver may be returned if is not present in the store,
-    eg, if *paths* were substituted from a binary cache.
+    Prints a set of derivation files (`.drv`) which are supposed produce
+    said paths when realized. Might print nothing, for example for source paths
+    or paths subsituted from a binary cache.
 
   - `--graph`\
     Prints the references graph of the store paths *paths* in the format

doc/manual/src/command-ref/nix-store/realise.md

@@ -15,6 +15,7 @@ Each of *paths* is processed as follows:
   1. If it is not [valid], substitute the store derivation file itself.
   2. Realise its [output paths]:
     - Try to fetch from [substituters] the [store objects] associated with the output paths in the store derivation's [closure].
+      - With [content-addressed derivations] (experimental): Determine the output paths to realise by querying content-addressed realisation entries in the [Nix database].
     - For any store paths that cannot be substituted, produce the required store objects. This involves first realising all outputs of the derivation's dependencies and then running the derivation's [`builder`](@docroot@/language/derivations.md#attr-builder) executable. <!-- TODO: Link to build process page #8888 -->
 - Otherwise, and if the path is not already valid: Try to fetch the associated [store objects] in the path's [closure] from [substituters].
 
@@ -27,6 +28,7 @@ If no substitutes are available and no store derivation is given, realisation fa
 [store objects]: @docroot@/glossary.md#gloss-store-object
 [closure]: @docroot@/glossary.md#gloss-closure
 [substituters]: @docroot@/command-ref/conf-file.md#conf-substituters
+[content-addressed derivations]: @docroot@/contributing/experimental-features.md#xp-feature-ca-derivations
 [Nix database]: @docroot@/glossary.md#gloss-nix-database
 
 The resulting paths are printed on standard output.

doc/manual/src/command-ref/opt-common.md

@@ -85,7 +85,7 @@ Most commands in Lix accept the following command-line options:
 
   - `multiline-with-logs`
 
-    Display the raw logs, with a progress bar and activities each in a new line at the bottom.
+    Displayes the raw logs, with a progress bar and activities each in a new line at the bottom.
 
 
 - <span id="opt-no-build-output">[`--no-build-output`](#opt-no-build-output)</span> / `-Q`

doc/manual/src/contributing/hacking.md

@@ -39,28 +39,17 @@ $ nix-shell -A native-clangStdenvPackages
 
 ### Building from the development shell
 
-Run a clean build and test with `just clean setup build install test`.
-
-You can also run the unit tests and integration tests separately:
+You can build and test Lix with just:
 
 ```bash
-$ just setup build test-unit
-$ just install test-integration
+$ just setup
+$ just build
+$ just test --suite=check
+$ just install
+$ just test --suite=installcheck
 ```
 
-Many targets have a `-custom` variant which pass extra arguments to `meson`.
-For example, to work on both Lix and nix-eval-jobs you can run:
-
-```
-$ just setup-custom -Dnix-eval-jobs=enabled
-$ # or
-$ mesonFlags=-Dnix-eval-jobs=enabled just setup
-```
-
-Note that only targets which don't accept extra arguments can be used when
-running multiple targets at once; `just setup build` is fine, but `just
-setup-custom build` is an error. The `test` target is usually the last one to
-run, so it always accepts extra arguments.
+(Check and installcheck may both be done after install, allowing you to omit the --suite argument entirely, but this is the order package.nix runs them in.)
 
 You can also build Lix manually:
 
@@ -148,11 +137,10 @@ You can also build Lix for one of the [supported platforms](#platforms).
 
 Lix can be built for various platforms, as specified in [`flake.nix`]:
 
-[`flake.nix`]: https://git.lix.systems/lix-project/lix/src/branch/main/flake.nix
+[`flake.nix`]: https://git.lix.systems/lix-project/lix/lix/branch/main/flake.nix
 
 - `x86_64-linux`
 - `x86_64-darwin`
-- `x86_64-freebsd`
 - `i686-linux`
 - `aarch64-linux`
 - `aarch64-darwin`
@@ -229,7 +217,7 @@ Lix uses a string with the following format to identify the *system type* or *pl
 
 It is set when Lix is compiled for the given system, and determined by [Meson's `host_machine.cpu_family()` and `host_machine.system()` values](https://mesonbuild.com/Reference-manual_builtin_host_machine.html).
 
-For historic reasons and backward-compatibility, some CPU and OS identifiers are translated from the GNU Autotools naming convention in [`meson.build`](https://git.lix.systems/lix-project/lix/src/branch/main/meson.build) as follows:
+For historic reasons and backward-compatibility, some CPU and OS identifiers are translated from the GNU Autotools naming convention in [`meson.build`](https://git.lix.systems/lix-project/lix/blob/main/meson.build) as follows:
 
 | `host_machine.cpu_family()`             | Nix                 |
 |----------------------------|---------------------|
@@ -256,13 +244,13 @@ To build with one of those environments, you can use
 $ nix build .#nix-ccacheStdenv
 ```
 
-for <a id="nix-with-flakes">flake-enabled Nix</a>, or
+for flake-enabled Nix, or
 
 ```console
 $ nix-build --attr nix-ccacheStdenv
 ```
 
-for <a id="classic-nix">classic Nix</a>.
+for classic Nix.
 
 You can use any of the other supported environments in place of `nix-ccacheStdenv`.
 
@@ -463,11 +451,11 @@ The following metadata properties are supported for builtin functions:
 * `implementation` (optional): a C++ expression specifying the implementation of the builtin.
   It must be a function of signature `void(EvalState &, PosIdx, Value * *, Value &)`.
   If not specified, defaults to `prim_${name}`.
-* `renameInGlobalScope` (optional): whether the definition should be "hidden" in the global scope by prefixing its name with two underscores.
+* `renameInGlobalScope` (optional): whether the definiton should be "hidden" in the global scope by prefixing its name with two underscores.
   If not specified, defaults to `true`.
 * `args` (required): list containing the names of the arguments, as shown in the documentation.
   All arguments must be listed here since the function arity is derived as the length of this list.
-* `experimental_feature` (optional): the user-facing name of the experimental feature which needs to be enabled for the builtin function to be available.
+* `experimental_feature` (optional): the user-facing name of the experimental feature which needs to be enabled for the bultin function to be available.
   If not specified, no experimental feature is required.
 
 New builtin function definition files must be added to `lix/libexpr/builtins` and registered in the `builtin_definitions` list in `lix/libexpr/meson.build`.

doc/manual/src/contributing/testing.md

@@ -449,6 +449,9 @@ I grepped `lix/` for `get[eE]nv\("` to find the mentions in Lix code.
 - `NIX_CLIENT_PACKAGE` - Runs the test suite against an alternate Nix client with the current daemon.
 
   **Expected value**: something like `/nix/store/...-nix-2.18.2`
+- `NIX_TESTS_CA_BY_DEFAULT` - Pass `__contentAddressed`, `outputHashMode` and `outputHashAlgo` to builds of some input-addressed derivations in the test suite.
+
+  **Expected value**: 1
 - `TEST_DATA` - Not an environment variable! This is used in repl characterization tests to refer to `tests/functional/repl_characterization/data`.
   More specifically, that path is replaced with the string `$TEST_DATA` in output for reproducibility.
 - `TEST_HOME` (output) - Set to the temporary directory that is set as `$HOME` inside the tests, underneath `$TEST_ROOT`.

doc/manual/src/glossary.md

@@ -41,6 +41,12 @@
 
   [realise]: #gloss-realise
 
+- [content-addressed derivation]{#gloss-content-addressed-derivation}
+
+  A derivation which has the
+  [`__contentAddressed`](./language/advanced-attributes.md#adv-attr-__contentAddressed)
+  attribute set to `true`.
+
 - [fixed-output derivation]{#gloss-fixed-output-derivation}
 
   A derivation which includes the
@@ -95,7 +101,7 @@
 
   See [File System Object](@docroot@/architecture/file-system-object.md) for details.
 
-  [file system object]: #gloss-store-path
+  [file system object]: #gloss-file-system-object
 
 - [store object]{#gloss-store-object}
 
@@ -108,13 +114,14 @@
 - [input-addressed store object]{#gloss-input-addressed-store-object}
 
   A store object produced by building a
+  non-[content-addressed](#gloss-content-addressed-derivation),
   non-[fixed-output](#gloss-fixed-output-derivation)
   derivation.
 
 - [output-addressed store object]{#gloss-output-addressed-store-object}
 
   A [store object] whose [store path] is determined by its contents.
-  This includes derivations and the outputs of [fixed-output derivations](#gloss-fixed-output-derivation).
+  This includes derivations, the outputs of [content-addressed derivations](#gloss-content-addressed-derivation), and the outputs of [fixed-output derivations](#gloss-fixed-output-derivation).
 
 - [substitute]{#gloss-substitute}
 
@@ -242,7 +249,7 @@
   links.  NARs are generated and unpacked using `nix-store --dump`
   and `nix-store --restore`.
 
-- [`∅`]{#gloss-empty-set}
+- [`∅`]{#gloss-emtpy-set}
 
   The empty set symbol. In the context of profile history, this denotes a package is not present in a particular version of the profile.
 

doc/manual/src/introduction.md

@@ -148,7 +148,7 @@ paths) are set.
 
 For example, the following command gets all dependencies of the
 Pan newsreader, as described by [its
-Nix expression](https://github.com/NixOS/nixpkgs/blob/master/pkgs/by-name/pa/pan/package.nix):
+Nix expression](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/newsreaders/pan/default.nix):
 
 ```console
 $ nix-shell '<nixpkgs>' --attr pan

doc/manual/src/language/advanced-attributes.md

@@ -209,8 +209,15 @@ Derivations can declare some infrequently used optional attributes.
 
   - [`__contentAddressed`]{#adv-attr-__contentAddressed}
     > **Warning**
-    > This attribute is part of a removed [experimental feature](@docroot@/contributing/experimental-features.md).
-    > Setting this flag *will* cause eval errors.
+    > This attribute is part of an [experimental feature](@docroot@/contributing/experimental-features.md).
+    >
+    > To use this attribute, you must enable the
+    > [`ca-derivations`](@docroot@/contributing/experimental-features.md#xp-feature-ca-derivations) experimental feature.
+    > For example, in [nix.conf](../command-ref/conf-file.md) you could add:
+    >
+    > ```
+    > extra-experimental-features = ca-derivations
+    > ```
 
     If this attribute is set to `true`, then the derivation
     outputs will be stored in a content-addressed location rather than the
@@ -254,7 +261,7 @@ Derivations can declare some infrequently used optional attributes.
     useful for very trivial derivations (such as `writeText` in Nixpkgs)
     that are cheaper to build than to substitute from a binary cache.
 
-    You may disable the effects of this attribute by enabling the
+    You may disable the effects of this attibute by enabling the
     `always-allow-substitutes` configuration option in Lix.
 
     > **Note**

doc/manual/src/language/values.md

@@ -164,7 +164,7 @@ Note that lists are only lazy in values, and they are strict in length.
 
 An attribute set is a collection of name-value-pairs (called *attributes*) enclosed in curly brackets (`{ }`).
 
-An attribute name can be an identifier or a [string](#type-string).
+An attribute name can be an identifier or a [string](#string).
 An identifier must start with a letter (`a-z`, `A-Z`) or underscore (`_`), and can otherwise contain letters (`a-z`, `A-Z`), numbers (`0-9`), underscores (`_`), apostrophes (`'`), or dashes (`-`).
 
 > *name* = *identifier* | *string* \

doc/manual/src/package-management/basic-package-mgmt.md

@@ -126,7 +126,7 @@ $ nix-env --install --attr nixpkgs.subversion
 ```
 
 will install the package called `subversion` from `nixpkgs` channel (which is, of course, the
-[Subversion version management system](https://subversion.apache.org/)).
+[Subversion version management system](http://subversion.tigris.org/)).
 
 > **Note**
 >

doc/manual/src/package-management/garbage-collection.md

@@ -71,62 +71,3 @@ $ nix-collect-garbage -d
 ```
 
 is a quick and easy way to clean up your system.
-
-## Garbage Collector Roots
-
-### Explicit roots
-
-All store paths to which there are symlinks in the directory
-`prefix/nix/var/nix/gcroots` will be used as roots by the garbage
-collector. For instance, the following command makes the path
-`/nix/store/d718ef...-foo` a root of the collector:
-
-```console
-$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar
-```
-
-That is, after this command, the garbage collector will not remove
-`/nix/store/d718ef...-foo` or any of its dependencies.
-
-Subdirectories of `prefix/nix/var/nix/gcroots` are also searched for
-symlinks.
-
-Symlinks may also point to paths outside the nix store. If the
-destination of the symlink is itself a symlink to a store path, it
-is also considered a root. This style of GC root is called an
-"indirect root", and is created by tools like `nix-build` to avoid
-garbage-collecting paths that are being used on-the-fly rather than
-installed in profiles.
-
-
-### In-use roots
-
-Lix will also perform a best-effort detection of paths that are in use
-by running processes when scanning for garbage collection roots, to
-avoid removing paths that are still needed by running processes.
-
-Exact details vary between platforms, but the following will generally
-be taken into account:
-
-- Executables in the store that are currently running;
-- Other files in the store that are mapped into a process's address space (e.g. shared libraries);
-- Files in the store to which processes have open handles;
-- Store paths found in processes' environment variables.
-
-Note that this detection is susceptible to missing paths that may still be in use for multiple reasons:
-
-- Time-of-check-to-time-of-use (TOCTTOU): new processes may appear
-  after Lix has enumerated the currently running processes, and will
-  not be taken into account;
-- Access privileges: if the garbage collection is not running as the
-  root user (this is typically the case for single-user
-  installations), it will not be able to scan processes belonging to
-  other users;
-- Other types of references: store paths may be stored in parts of the
-  filesystem (e.g. databases) or process memory (e.g. environment
-  variables changed since the start of the process) that Lix does not
-  scan.
-
-For this reason, it is recommended to create explicit roots whenever
-using store paths that aren't obtained from some existing explicit GC
-root.

doc/manual/src/package-management/garbage-collector-roots.md

@@ -0,0 +1,18 @@
+# Garbage Collector Roots
+
+The roots of the garbage collector are all store paths to which there
+are symlinks in the directory `prefix/nix/var/nix/gcroots`. For
+instance, the following command makes the path
+`/nix/store/d718ef...-foo` a root of the collector:
+
+```console
+$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar
+```
+
+That is, after this command, the garbage collector will not remove
+`/nix/store/d718ef...-foo` or any of its dependencies.
+
+Subdirectories of `prefix/nix/var/nix/gcroots` are also searched for
+symlinks. Symlinks to non-store paths are followed and searched for
+roots, but symlinks to non-store paths *inside* the paths reached in
+that way are not followed to prevent infinite recursion.

doc/manual/src/protocols/derivation-aterm.md

@@ -2,8 +2,18 @@
 
 For historical reasons, [derivations](@docroot@/glossary.md#gloss-store-derivation) are stored on-disk in [ATerm](https://homepages.cwi.nl/~daybuild/daily-books/technology/aterm-guide/aterm-guide.html) format.
 
-Derivations are serialised in the following format:
+Derivations are serialised in one of the following formats:
 
-```
-Derive(...)
-```
+- ```
+  Derive(...)
+  ```
+
+  For all stable derivations.
+
+- ```
+  DrvWithVersion(<version-string>, ...)
+  ```
+
+  The only `version-string`s that are in use today are for [experimental features](@docroot@/contributing/experimental-features.md):
+
+  - `"xp-dyn-drv"` for the [`dynamic-derivations`](@docroot@/contributing/experimental-features.md#xp-feature-dynamic-derivations) experimental feature.

doc/manual/src/release-notes/rl-2.18.md

@@ -13,7 +13,7 @@
 
 - The `discard-references` feature has been stabilized.
   This means that the
-  `unsafeDiscardReferences`
+  [unsafeDiscardReferences](@docroot@/contributing/experimental-features.md#xp-feature-discard-references)
   attribute is no longer guarded by an experimental flag and can be used
   freely.
 

doc/manual/src/release-notes/rl-2.92.md

@@ -1,4 +1,137 @@
 # Lix 2.92 "Bombe glacée" (2025-01-18)
+# Lix 2.92.3 (2025-06-30)
+
+## Fixes
+- Revert CVE-2025-52992 failed mitigation [fj#883](https://git.lix.systems/lix-project/lix/issues/883) [fj#887](https://git.lix.systems/lix-project/lix/issues/887) [cl/3432](https://gerrit.lix.systems/c/lix/+/3432) [cl/3525](https://gerrit.lix.systems/c/lix/+/3525) [cl/3526](https://gerrit.lix.systems/c/lix/+/3526) [cl/3527](https://gerrit.lix.systems/c/lix/+/3527)
+
+  Following the initial mitigation of **CVE-2025-52992** in `cl/3432`, we
+  received reports of **unexpected deletion of in-use store paths**.
+
+  Upon investigation, we found that the patch did **not correctly cancel all
+  automatic deleters**, resulting in potentially critical path loss during normal
+  operation.
+
+  Given the severity and time-sensitive nature of the situation ([see incident
+  report](https://lix.systems/blog/2025-06-27-lix-critical-bug/)), we evaluated
+  possible options to repair the behavior safely. However, we concluded that a
+  rushed fix would either
+
+  * **Overdelete**, i.e. breaking running systems, or,
+  * **Underdelete**, effectively **reopening CVE-2025-52992** while leaving
+    orphaned paths behind.
+
+  As **CVE-2025-52992 has no known exploit vector**, and correctness is critical
+  in the Lix project, we have **fully reverted the previous mitigations**.
+
+  The affected patches (`cl/3432`) have been rolled back for the time being.
+
+  Moving forward, the Lix team will rework this code path in a **long-term,
+  correctness-first fix** on the main branch. We will explore backporting it to
+  stable channels once its safety is assured.
+
+  We are deeply sorry for the stability incident and the Lix team remain
+  available for assisting you in recovering your systems.
+
+  Many thanks to [Raito Bezarius](https://git.lix.systems/raito) and [eldritch horrors](https://git.lix.systems/pennae) for this.
+- Fallback to safe temp dir when build-dir is unwritable [fj#876](https://git.lix.systems/lix-project/lix/issues/876) [cl/3503](https://gerrit.lix.systems/c/lix/+/3503)
+
+  Non-daemon builds started failing with a permission error after introducing the `build-dir` option:
+
+  ```
+  $ nix build --store ~/scratch nixpkgs#hello --rebuild
+  error: creating directory '/nix/var/nix/builds/nix-build-hello-2.12.2.drv-0': Permission denied
+  ```
+
+  This happens because:
+
+  1. These builds are not run via the daemon, which owns `/nix/var/nix/builds`.
+  2. The user lacks permissions for that path.
+
+  We considered making `build-dir` a store-level option and defaulting it to `<chroot-root>/nix/var/nix/builds` for chroot stores, but opted instead for a fallback: if the default fails, Nix now creates a safe build directory under `/tmp`.
+
+  To avoid CVE-2025-52991, the fallback uses an extra path component between `/tmp` and the build dir.
+
+  **Note**: this fallback clutters `/tmp` with build directories that are not cleaned up. To prevent this, explicitly set `build-dir` to a path managed by Lix, even for local workloads.
+
+  Many thanks to [Raito Bezarius](https://git.lix.systems/raito) and [eldritch horrors](https://git.lix.systems/pennae) for this.
+
+
+# Lix 2.92.2 (2025-06-23)
+
+## Breaking Changes
+- Fixed output derivations can be run using `pasta` network isolation [fj#285](https://git.lix.systems/lix-project/lix/issues/285) [cl/3430](https://gerrit.lix.systems/c/lix/+/3430)
+
+  Fixed output derivations traditionally run in the host network namespace.
+  On Linux this allows such derivations to communicate with other sandboxes
+  or the host using the abstract Unix domains socket namespace; this hasn't
+  been unproblematic in the past and has been used in two distinct exploits
+  to break out of the sandbox. For this reason fixed output derivations can
+  now run in a network namespace (provided by [`pasta`]), restricted to TCP
+  and UDP communication with the rest of the world. When enabled this could
+  be a breaking change and we classify it as such, even though we don't yet
+  enable or require such isolation by default. We may enforce this in later
+  releases of Lix once we have sufficient confidence that breakage is rare.
+
+  [`pasta`]: https://passt.top/
+
+  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) and [puck](https://git.lix.systems/puck) for this.
+
+## Fixes
+- Always clean up scratch paths after derivations failed to build [cl/3432](https://gerrit.lix.systems/c/lix/+/3432)
+
+  Previously, scratch paths created during builds were not always cleaned up if
+  the derivation failed, potentially leaving behind unnecessary temporary files
+  or directories in the Nix store.
+
+  This fix ensures that such paths are consistently removed after a failed build,
+  improving Nix store hygiene, hardening Lix against mis-reuse of failed builds
+  scratch paths.
+
+  Many thanks to [Raito Bezarius](https://git.lix.systems/raito) and [eldritch horrors](https://git.lix.systems/pennae) for this.
+- `build-dir` no longer defaults to `temp-dir` [cl/3431](https://gerrit.lix.systems/c/lix/+/3431)
+
+  The directory in which temporary build directories are created no longer defaults
+  to the value of the `temp-dir` setting to avoid builders making their directories
+  world-accessible. This behavior has been used to escape the build sandbox and can
+  cause build impurities even when not used maliciously. We now default to `builds`
+  in `NIX_STATE_DIR` (which is `/nix/var/nix/builds` in the default configuration).
+
+  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) for this.
+- Forbid impure path accesses in pure evaluation mode again [cl/2708](https://gerrit.lix.systems/c/lix/+/2708)
+
+  Lix 2.92.0 mistakenly started allowing the access to ancestors of allowed paths in pure evaluation mode.
+  This made it possible to bypass the purity restrictions, for example by copying arbitrary files to the store:
+  ```nix
+  builtins.path {
+    path = "/";
+    filter = …;
+  }
+  ```
+  Restore the previous behaviour of prohibiting such impure accesses.
+
+  Many thanks to [alois31](https://git.lix.systems/alois31) for this.
+- Parsing failures in flake.lock no longer crash Lix [fj#559](https://git.lix.systems/lix-project/lix/issues/559) [cl/2401](https://gerrit.lix.systems/c/lix/+/2401)
+
+  Failure to parse `flake.lock` no longer hard-crashes Lix and instead produces a nice error message.
+
+  ```
+  error:
+         … while updating the lock file of flake 'git+file:///Users/jade/lix/lix2'
+
+         … while parsing the lock file at /nix/store/mm5dqh8a729yazzj82cjffxl97n5c62s-source//flake.lock
+
+         error: [json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - invalid literal;
+   last read: '#'
+  ```
+
+  Many thanks to [gilice](https://git.lix.systems/gilice) for this.
+- Fix `--debugger --ignore-try` [cl/2440](https://gerrit.lix.systems/c/lix/+/2440)
+
+  When in debug mode (e.g. from using the `--debugger` flag), enabling [`ignore-try`](@docroot@/command-ref/conf-file.md#conf-ignore-try) once again properly disables debug REPLs within [`builtins.tryEval`](@docroot@/language/builtins.md#builtins-tryEval) calls. Previously, a debug REPL would be started as if `ignore-try` was disabled, but that REPL wouldn't actually be in debug mode, and upon exiting the REPL the evaluating process would segfault.
+
+  Many thanks to [Dusk Banks](https://git.lix.systems/bb010g) for this.
+
+
 
 
 # Lix 2.92.0 (2025-01-18)
@@ -51,8 +184,8 @@
       {
         formatter = eachSystem (pkgs:
           pkgs.writeShellScriptBin "formatter" ''
-            if [[ $# = 0 ]]; then set -- .; fi
-            exec "${pkgs.nixfmt-rfc-style}/bin/nixfmt" "$@"
+            if [[ $# = 0 ]]; set -- .; fi
+            exec "${pkgs.nixfmt-rfc-style}/bin/nixfmt "$@"
           '');
       };
   }

doc/manual/src/release-notes/rl-2.93.md

@@ -1,715 +0,0 @@
-# Lix 2.93 "Bici Bici" (2025-05-09)
-
-
-# Lix 2.93.0 (2025-05-09)
-## Breaking Changes
-
-- more deprecated features
-
-  This release cycle features a new batch of deprecated (anti-)features.
-  You can opt in into the old behavior with `--extra-deprecated-features` or any equivalent configuration option.
-
-  - `cr-line-endings`: Current handling of CR (`\r`) or CRLF (`\r\n`) line endings in Nix is inconsistent and broken, and will lead to unexpected evaluation results with certain strings. Given that fixing the semantics might silently alter the evaluation result of derivations, the only option at the moment is to disallow them altogether. More proper support for CRLF is planned to be added back again in the future. Until then, all files must use `\n` exclusively.
-  - `nul-bytes`: Currently the Nix grammar allows NUL bytes (`\0`) in strings, and thus indirectly also in identifiers. Unfortunately, several core parts of the code base still work with NUL-terminated strings and cannot easily be migrated. Also note that it is still possible to introduce NUL bytes and thus problematic behavior via other means, those are tracked separately.
-
-  Many thanks to [piegames](https://git.lix.systems/piegames) and [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-- Removal of the `recursive-nix` experimental feature [fj#767](https://git.lix.systems/lix-project/lix/issues/767) [cl/2872](https://gerrit.lix.systems/c/lix/+/2872)
-
-  The `recursive-nix` experimental feature and all associated code have been removed.
-
-  `recursive-nix` enabled running Nix operations (like evaluations and builds) *inside* a derivation builder. This worked by spawning a temporary Nix daemon socket within the build environment, allowing the derivation to emit outputs that appeared in the outer store. This was primarily used to prototype **dynamic derivations** (dyndrvs), where build plans are generated on-the-fly during a build.
-
-  However, this approach introduced critical issues:
-
-  - It entrenched the legacy Nix daemon protocol as part of the derivation ABI, which is a blocker for future stabilization.
-  - It imposed tight coupling between sandbox setup code and knowledge of Nix internals, complicating refactoring and long-term maintenance.
-  - It was never intended to be the final design for dynamic derivations. The original Nix implementation team, who are leading dyndrv development, have agreed it will be replaced (likely via `varlink` or similar) before any stabilization.
-  - There is currently no known usage of `recursive-nix` on `lix` or elsewhere **in production**.
-
-  If you're using `recursive-nix` for something niche or experimental, we'd love to hear from you on the RFD issue.
-  You can still run `nix` inside a builder manually if needed — including with isolated user namespaces and fake stores — but the special daemon-handshake machinery is gone.
-
-  This removal unblocks several important internal cleanups.
-
-  Many thanks to [Raito Bezarius](https://git.lix.systems/raito) for this.
-
-- Flake inputs/`builtins.fetchTree` invocations with `type = "file"` now have consistent (but different from previous versions) resulting paths [fj#750](https://git.lix.systems/lix-project/lix/issues/750) [cl/2864](https://gerrit.lix.systems/c/lix/+/2864)
-
-  Previously `fetchTree { type = "file"; url = "...", narHash = "sha256-..."; }` could return a different result depending on whether someone has run `nix store add-path --name source ...` on a path with the same `narHash` as the flake input/`fetchTree` invocation (or if such a path exists in an accessible binary cache).
-
-  In the past `type = "file"` flake inputs were, in contrast to all other flake inputs, hashed in *flat* hash mode rather than *recursive* hash mode.
-  The difference between the two is that *flat* mode hashes are just what you get from `sha256sum` of a single file, whereas *recursive* hashes are the SHA256 sum of a NAR (Nix ARchive, a deterministic tarball-like format) of a file tree.
-
-  Much of flakes assumes that everything is recursive-hashed including `nix flake archive`, substitution of flake inputs from binary caches, and more, which led to the substitution path code being taken if such a path is present, yielding a different store path non-deterministically.
-
-  To fix this non-deterministic evaluation bug, we needed to break derivation hash stability, so some Nix evaluations now produce different results than previous versions of Lix.
-  Lix now has consistent behaviour with CppNix 2.24 with respect to `file` flake inputs: they are *always* recursively hashed.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Builders are always started in a fresh cgroup namespace [cl/1996](https://gerrit.lix.systems/c/lix/+/1996)
-
-  If you haven't enabled the experimental `cgroups` feature, Nix previously launched builder processes in new namespaces but did not create new cgroup namespaces. As a result, derivations could access and observe the parent cgroup namespace.
-
-  Although this update introduces a breaking change, it ensures that all derivations now start in a fresh cgroup namespace by default. This reduces potential impurities observable within the sandbox, improving the likelihood of reproducible builds across different environments.
-
-  Many thanks to [Raito Bezarius](https://git.lix.systems/raito) for this.
-
-- `nix-instantiate --parse` outputs json [fj#487](https://git.lix.systems/lix-project/lix/issues/487) [nix#11124](https://github.com/NixOS/nix/issues/11124) [nix#4726](https://github.com/NixOS/nix/issues/4726) [nix#3077](https://github.com/NixOS/nix/issues/3077) [cl/2190](https://gerrit.lix.systems/c/lix/+/2190)
-
-  `nix-instantiate --parse` does not print out the AST in a Nix-like format anymore.
-  Instead, it now prints a JSON representation of the internal expression tree.
-  Tooling should not rely on the stdout of `nix-instantiate --parse`.
-
-  We've done our best to ensure that the new behavior is as compatible with the old one as possible.
-  If you depend on the old behavior in ways that are not covered anymore or are otherwise negatively affected by this change,
-  then please reach out so that we can find a sustainable solution together.
-
-  Many thanks to [piegames](https://git.lix.systems/piegames) and [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-- Remove experimental repl-flake [gh#10103](https://github.com/NixOS/nix/issues/10103) [fj#557](https://git.lix.systems/lix-project/lix/issues/557) [gh#10299](https://github.com/NixOS/nix/pull/10299) [cl/2147](https://gerrit.lix.systems/c/lix/+/2147)
-
-  The `repl-flake` experimental feature flag has been removed, its functionality is now the default when `flakes` experimental feature is active. The `nix repl` command now works like the rest of the new CLI in that `nix repl {path}` now tries to load a flake at `{path}` (or fails if the `flakes` experimental feature isn't enabled).
-
-  Many thanks to [Jonathan De Troye](https://github.com/detroyejr) and [KFears](https://git.lix.systems/kfearsoff) for this.
-
-
-## Features
-
-- `lix foo` now invokes `lix-foo` from PATH [cl/2119](https://gerrit.lix.systems/c/lix/+/2119)
-
-  Lix introduces the ability to extend the Nix command line by adding custom
-  binaries to the `PATH`, similar to how Git integrates with other tools. This
-  feature allows developers and end users to enhance their workflow by
-  integrating additional functionalities directly into the Nix CLI.
-
-  #### Examples
-
-  For example, a user can create a custom deployment tool, `lix-deploy-tool`, and
-  place it in their `PATH`. This allows them to execute `lix deploy-tool`
-  directly from the command line, streamlining the process of deploying
-  applications without needing to switch contexts or use separate commands.
-
-  #### Limitations
-
-  For now, autocompletion is supported to discover new custom commands, but the
-  documentation will not render them. Argument autocompletion of the custom
-  command is not supported either.
-
-  This is also locked behind a new experimental feature called
-  `lix-custom-sub-commands` to enable developing all the required features.
-
-  Only the top-level `lix` command can be extended, this is an artificial
-  limitation for the time being until we flesh out this feature.
-
-  #### Outline
-
-  In the future, this feature may pave the way for moving the Flake subcommand
-  line to its own standalone binary, allowing for a more focused approach to
-  managing Nix Flakes while letting the community explore alternatives to
-  dependency management.
-
-  Many thanks to [Raito Bezarius](https://git.lix.systems/raito) for this.
-
-- `nix-env --install` now accepts a `--priority` flag [cl/2607](https://gerrit.lix.systems/c/lix/+/2607)
-
-  `nix-env --install` now has an optional `--priority` flag.
-
-  Previously, it was only possible to specify a priority by adding a
-  `meta.priority` attribute to a derivation. `meta` attributes only exist during
-  eval, so that wouldn't work for installing a store path. It was also possible
-  to change a priority after initial installation using `nix-env --set-flag`,
-  however if there is already a conflict that needs to be resolved via priorities,
-  this will not work.
-
-  Now, a priority can be set at install time using `--priority`, which allows for
-  cleanly overriding the priority at install time.
-
-  #### Example
-
-  ```console
-  $ nix-build
-  $ nix-env --install --priority 100 ./result
-  ```
-
-  Many thanks to [Andrew Hamon](https://github.com/andrewhamon) for this.
-
-- Add support for eBPF USDT/dtrace probes inside Lix [fj#727](https://git.lix.systems/lix-project/lix/issues/727) [cl/2884](https://gerrit.lix.systems/c/lix/+/2884)
-
-  eBPF tracers like `bpftrace` and `dtrace` are a group of similar tools for debugging production systems.
-  User-space statically defined tracing probes (USDT) allow for defining zero or near-zero disabled-probe-effect probes, thus allowing instrumentation of hot paths in production builds.
-  Lix now has internal support for defining these probes and has shipped its first probe.
-
-  As of this writing it is available by default in the Linux build of Lix.
-
-  To try it out on Linux, you can use the following example command:
-
-  ```
-  $ sudo bpftrace -l 'usdt:/path/to/liblixstore.so:*:*'
-  usdt:/path/to/liblixstore.so:lix_store:filetransfer__read
-
-  $ sudo bpftrace -e 'usdt:*:lix_store:filetransfer__read { printf("%s read %d\n", str(arg0), arg1); }'
-  Attaching 1 probe...
-  https://cache.nixos.org/wvpzaycmvs39h5bcsfrxkjsg48mj4h73.narinf.. read 8192
-  https://cache.nixos.org/wvpzaycmvs39h5bcsfrxkjsg48mj4h73.narinf.. read 8192
-  https://cache.nixos.org/nar/1qshsc30nlarzdig0v9b1aasdkwaxhnv0a0.. read 65536
-  https://cache.nixos.org/nar/1qshsc30nlarzdig0v9b1aasdkwaxhnv0a0.. read 65536
-  ```
-
-  Note that bpftrace does not offer any way to list the arguments to USDT probes in a human readable form.
-  To get the probe definitions, see the `*.d` files in the Lix source code, for example, `lix/libstore/trace-probes.d`.
-
-  For more resources on eBPF/bpftrace and dtrace, see:
-  * The book "BPF Performance Tools" by Brendan Gregg, which discusses bpftrace at length.
-  * <https://ebpf.io/get-started/>
-  * [Illumos' dtrace book](https://illumos.org/books/dtrace/preface.html)
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-
-## Improvements
-
-- Always print `post-build-hook` logs [fj#675](https://git.lix.systems/lix-project/lix/issues/675) [cl/2801](https://gerrit.lix.systems/c/lix/+/2801)
-
-  Logs of `post-build-hook` are now printed unconditionally.
-  They used to be tied to whether print-build-logs is set, which made debugging them a nightmare when they fail, since the failure output would be eaten if build logs are disabled.
-  Most usages of `post-build-hook` are pretty quiet especially compared to build logs, so it should not be that bothersome to not be able to turn off.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Crashes land in syslog now [cl/2640](https://gerrit.lix.systems/c/lix/+/2640)
-
-  When Lix crashes with unexpected exceptions and in some other conditions, it prints bug reporting instructions.
-  Previously, these only landed in stderr and not in syslog.
-  However, on larger Lix installations, it may be the case that Lix crashes in the client without the logs landing in the system logs, which impeded diagnosis.
-
-  Now, such crashes always land in syslog too.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Deletion of specific paths no longer fails fast [cl/2778](https://gerrit.lix.systems/c/lix/+/2778)
-
-  `nix-store --delete` and `nix store delete` now continue deleting
-  paths even if some of the given paths are still live. An error is only
-  thrown once deletion of all the given paths has been
-  attempted. Previously, if some paths were deletable and others
-  weren't, the deletable ones would be deleted iff they preceded the
-  live ones in lexical sort order.
-
-  The error message for still-live paths no longer reports the paths
-  that could not be deleted, because there could potentially be many of
-  these.
-
-  Many thanks to [lheckemann](https://git.lix.systems/lheckemann) for this.
-
-- `--skip-live` for path deletion [cl/2778](https://gerrit.lix.systems/c/lix/+/2778)
-
-  `nix-store --delete` and `nix store delete` now support a
-  `--skip-live` option and a `--delete-closure` option.
-
-  This makes custom garbage-collection logic a lot easier to implement
-  and experiment with:
-
-  - Paths known to be large can be thrown at `nix store delete` without
-    having to manually filter out those that are still reachable from a
-    root, e.g.
-    `nix store delete /nix/store/*mbrola-voices*`
-
-  - The `--delete-closure` option allows extending this to paths that are
-    not large themselves but do have a large closure size, e.g.
-    `nix store delete /nix/store/*nixos-system-gamingpc*`.
-
-  - Other heuristics like atime-based deletion can be applied more
-    easily, because `nix store delete` once again takes over the task of
-    working out which paths can't be deleted.
-
-  Many thanks to [lheckemann](https://git.lix.systems/lheckemann) for this.
-
-- Allow `nix store diff-closures` to output JSON [cl/2360](https://gerrit.lix.systems/c/lix/+/2360)
-
-  Add the `--json` option to the `nix store diff-closures` command to allow users to collect diff information into a machine readable format.
-
-  ```bash
-  $ build/lix/nix/nix store diff-closures --json /run/current-system /nix/store/n1prick95pihd4lkv58nn3pzg1yivcdb-neovim-0.10.4/bin/nvim | jq | head -n 23
-  {
-    "packages": {
-      "02overridedns": {
-        "sizeDelta": -688,
-        "versionsAfter": [],
-        "versionsBefore": [
-          ""
-        ]
-      },
-      "50-coredump.conf": {
-        "sizeDelta": -1976,
-        "versionsAfter": [],
-        "versionsBefore": [
-          ""
-        ]
-      },
-      "Diff": {
-        "sizeDelta": -514864,
-        "versionsAfter": [],
-        "versionsBefore": [
-          "0.4.1"
-        ]
-      },
-  ```
-
-  Many thanks to [Xavier Maso](https://github.com/pamplemousse) for this.
-
-- Show all missing and unexpected arguments in erroneous function calls [cl/2477](https://gerrit.lix.systems/c/lix/+/2477)
-
-  When calling a function that expects an attribute set, lix will now show all
-  missing and unexpected arguments.
-  e.g. with `({ a, b, c } : a + b + c) { a = 1; d = 1; }` lix will now show the error:
-  ```
-  [...]
-  error: function 'anonymous lambda' called without required arguments 'b' and 'c' and with unexpected argument 'd'
-  [...]
-  ```
-  Previously lix would just show `b`.
-  Furthermore lix will now only suggest arguments that aren't yet used.
-  e.g. with `({ a?1, b?1, c?1 } : a + b + c) { a = 1; d = 1; e = 1; }` lix will now show the error:
-  ```
-  [...]
-  error: function 'anonymous lambda' called with unexpected arguments 'd' and 'e'
-         at «string»:1:2:
-              1| ({ a?1, b?1, c?1 } : a + b + c) { a = 1; d = 1; e = 1; }
-               |  ^
-         Did you mean one of b or c?
-  ```
-  Previously lix would also suggest `a`.
-  Suggestions are unfortunately still currently just for the first missing argument.
-
-  Many thanks to [Zitrone](https://git.lix.systems/quantenzitrone) for this.
-
-- REPL improvements [cl/2319](https://gerrit.lix.systems/c/lix/+/2319) [cl/2320](https://gerrit.lix.systems/c/lix/+/2320) [cl/2321](https://gerrit.lix.systems/c/lix/+/2321)
-
-  The REPL has seen various minor improvements:
-
-  - Variable declarations have been improved, making copy-pasting code from attrsets a lot easier:
-    - Declarations can now optionally end with a semicolon
-    - Multiple declarations can be done within one command, separated by semicolon
-    - The `foo.bar = "baz";` syntax from attrsets is also supported, however without the attrset merging rules and with restrictions on dynamic attrs like in `let` bindings.
-    - Variable names now use the proper Nix grammar rules, instead of a regex that only vaguely matched legal identifiers.
-  - Better error messages overall
-  - The `:env` command to print currently available variables now also works outside of debug mode
-  - Adding variables to the REPL now prints a small message on success
-
-  Many thanks to [piegames](https://git.lix.systems/piegames) for this.
-
-- Consistently use SRI hashes in hash mismatch errors [cl/2868](https://gerrit.lix.systems/c/lix/+/2868)
-
-  Previously there were a few weird cases (flake inputs, e.g., among others) where Lix would print the old Nix base-32 hash format (sha256:abcd...) rather than the newer [SRI base64 format](https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity) (sha256-AAAA...) that is used in most Lix hash mismatch errors.
-  This made it annoying to compare them to hashes shown by most of the modern UI surface of Lix which uses SRI.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Allow specifying ports for remote ssh[-ng] stores [cl/2432](https://gerrit.lix.systems/c/lix/+/2432)
-
-  You can now specify which port should be used for a remote ssh store (e.g. for remote/distributed builds) through a uri parameter.
-  E.g., when a remote builder `foo` is listening on port `1234` instead of the default, it can be specified like this `ssh://foo?port=1234`.
-
-  Many thanks to [seppel3210](https://github.com/Seppel3210) for this.
-
-- Implicit `__toString` now have stack trace entries [cl/3055](https://gerrit.lix.systems/c/lix/+/3055)
-
-  Coercion of attribute sets to strings via their `__toString` attribute now produce stack
-  frames pointing to the coercion site and the attribute definition. This makes locating a
-  coercion function error easier as the fault location is now more likely to be presented.
-
-  Previously:
-  ```
-  nix-repl> builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-  error:
-         … while calling the 'substring' builtin
-           at «string»:1:1:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               | ^
-
-         … caused by explicit throw
-           at «string»:1:48:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               |                                                ^
-
-         error: bar
-  ```
-
-  Now:
-  ```
-  nix-repl> builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-  error:
-         … while calling the 'substring' builtin
-           at «string»:1:1:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               | ^
-
-         … while converting a set to string
-           at «string»:1:25:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               |                         ^
-
-         … from call site
-           at «string»:1:29:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               |                             ^
-
-         … while calling '__toString'
-           at «string»:1:42:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               |                                          ^
-
-         … caused by explicit throw
-           at «string»:1:48:
-              1| builtins.substring 1 1 "${{ __toString = self: throw ''bar''; }}"
-               |                                                ^
-
-         error: bar
-  ```
-
-  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-
-## Fixes
-
-- Avoid unnecessarily killing processes for the build user's UID [nix#9142](https://github.com/NixOS/nix/issues/9142) [fj#667](https://git.lix.systems/lix-project/lix/issues/667)
-
-  We no longer kill all processes under the build user's UID before and after
-  builds on Linux with sandboxes enabled.
-
-  This avoids unrelated processes being killed. This might happen for instance,
-  if the user is running Lix inside a container, wherein the build users use the same UIDs as the daemon's.
-
-  Many thanks to [teofilc](https://git.lix.systems/teofilc) for this.
-
-- Forbid impure path accesses in pure evaluation mode again [cl/2708](https://gerrit.lix.systems/c/lix/+/2708)
-
-  Lix 2.92.0 mistakenly started allowing the access to ancestors of allowed paths in pure evaluation mode.
-  This made it possible to bypass the purity restrictions, for example by copying arbitrary files to the store:
-  ```nix
-  builtins.path {
-    path = "/";
-    filter = …;
-  }
-  ```
-  Restore the previous behaviour of prohibiting such impure accesses.
-
-  Many thanks to [alois31](https://git.lix.systems/alois31) for this.
-
-- Ctrl-C works correctly on macOS again [fj#729](https://git.lix.systems/lix-project/lix/issues/729) [cl/3066](https://gerrit.lix.systems/c/lix/+/3066)
-
-  Due to a kernel bug in macOS's `poll(2)` implementation where it would forget about event subscriptions, our detection of closed connections in the Lix daemon didn't work and left around lingering daemon processes.
-  We have rewritten that thread to use `kqueue(2)`, which is what the `poll(2)` implementation uses internally in the macOS kernel, so now Ctrl-C on clients will reliably terminate daemons once more.
-
-  This FD close monitoring has had the highest Apple bug ID references per line of code anywhere in the project, and hopefully not using poll anymore will stop us hitting bugs in poll.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Fetch peer PID for daemon connections on macOS [fj#640](https://git.lix.systems/lix-project/lix/issues/640) [cl/2453](https://gerrit.lix.systems/c/lix/+/2453)
-
-  `nix-daemon` will now fetch the peer PID for connections on macOS, to match behavior with Linux.
-  Besides showing up in the log output line, If `nix-daemon` is given an argument (such as `--daemon`)
-  that argument will be overwritten with the peer PID for the forked process that handles the connection,
-  which can be used for debugging purposes.
-
-  Many thanks to [lilyball](https://git.lix.systems/lilyball) for this.
-
-- Test group membership better on macOS [gh#5885](https://github.com/NixOS/nix/issues/5885) [cl/2566](https://gerrit.lix.systems/c/lix/+/2566)
-
-  `nix-daemon` will now test group membership better on macOS for `trusted-users` and `allowed-users`.
-  It not only fetches the peer gid (which fixes `@staff`) but it also asks opendirectory for group
-  membership checks instead of just using the group database, which means nested groups (like `@_developer`)
-  and groups with synthesized membership (like `@localaccounts`) will work.
-
-  Many thanks to [lilyball](https://git.lix.systems/lilyball) for this.
-
-- `nix store delete` no longer builds paths [cl/2782](https://gerrit.lix.systems/c/lix/+/2782)
-
-  `nix store delete` no longer realises the installables
-  specified. Previously, `nix store delete nixpkgs#hello` would download
-  hello only to immediately delete it again. Now, it exits with an error
-  if given an installable that isn't in the store.
-
-  Many thanks to [lheckemann](https://git.lix.systems/lheckemann) for this.
-
-- Fix nix-store --delete on paths with remaining referrers [cl/2783](https://gerrit.lix.systems/c/lix/+/2783)
-
-  Nix 2.5 introduced a regression whereby `nix-store --delete` and `nix
-  store delete` started to fail when trying to delete a path that was
-  still referenced by other paths, even if the referrers were not
-  reachable from any GC roots. The old behaviour, where attempting to
-  delete a store path would also delete its referrer closure, is now
-  restored.
-
-  Many thanks to [lheckemann](https://git.lix.systems/lheckemann) for this.
-
-- Add a straightforward way to detect if in a Nix3 Shell [nix#6677](https://github.com/NixOS/nix/issues/6677) [nix#3862](https://github.com/NixOS/nix/issues/3862) [cl/2090](https://gerrit.lix.systems/c/lix/+/2090)
-
-  Running `nix shell` or `nix develop` will now set `IN_NIX_SHELL` to
-  either `pure` or `impure`, depending on whether `--ignore-environment`
-  is passed. `nix develop` will always be an impure environment.
-
-  Many thanks to [Ersei Saggi](https://github.com/9p4) for this.
-
-- Fix experimental and deprecated features showing as integers in `nix config show --json` [fj#738](https://git.lix.systems/lix-project/lix/issues/738) [cl/2882](https://gerrit.lix.systems/c/lix/+/2882)
-
-  Internal changes in 2.92 caused `nix config show --json` to show deprecated and experimental features not as the list of named features 2.91 and earlier produced, but as integers. This has been fixed.
-
-  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-- `builtins.fetchTree` is no longer visible in `builtins` when flakes are disabled [cl/2399](https://gerrit.lix.systems/c/lix/+/2399)
-
-  `builtins.fetchTree` is the foundation of flake inputs and flake lock files, but is not fully specified in behaviour, which leads to regressions, behaviour differences with CppNix, and other unfun times.
-  It's gated behind the `flakes` experimental feature, but prior to now, would throw an uncatchable error at runtime when used without the `flakes` feature enabled.
-  Now it's like other builtins which are experimental feature gated, where it is not visible without the relevant feature enabled.
-
-  This fixes a bug in using Eelco Dolstra's version of flake-compat on Lix (and a divergence with CppNix): https://github.com/edolstra/flake-compat/issues/66
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- fix usage of `builtins.filterSource` and `builtins.path` with the filter argument when using chroot stores [nix#11503](https://github.com/NixOS/nix/issues/11503)
-
-  The semantics of `builtins.filterSource` (and the `filter` argument for
-  `builtins.path`) have been adjusted regarding how paths inside the Nix store
-  are handled.
-
-  Previously, when evaluating whether a path should be included, the filtering
-  function received the **physical path** if the source was inside the chroot store.
-
-  Now, it receives the **logical path** instead.
-
-  This ensures consistency in path handling and avoids potential
-  misinterpretations of paths within the evaluator, which led to various fallouts
-  mentioned in <https://github.com/NixOS/nixpkgs/pull/369694>.
-
-  Many thanks to [lily](https://git.lix.systems/lilyinstarlight), [alois31](https://git.lix.systems/alois31), and [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-- Fix `--help` formatting [fj#622](https://git.lix.systems/lix-project/lix/issues/622) [cl/2776](https://gerrit.lix.systems/c/lix/+/2776)
-
-  The help printed when invoking `nix` or `nix-store` and subcommands with `--help` previously contained garbled terminal escapes. These have been removed.
-
-  Many thanks to [lheckemann](https://git.lix.systems/lheckemann) for this.
-
-- Parsing failures in flake.lock no longer crash Lix [fj#559](https://git.lix.systems/lix-project/lix/issues/559) [cl/2401](https://gerrit.lix.systems/c/lix/+/2401)
-
-  Failure to parse `flake.lock` no longer hard-crashes Lix and instead produces a nice error message.
-
-  ```
-  error:
-         … while updating the lock file of flake 'git+file:///Users/jade/lix/lix2'
-
-         … while parsing the lock file at /nix/store/mm5dqh8a729yazzj82cjffxl97n5c62s-source//flake.lock
-
-         error: [json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - invalid literal;
-   last read: '#'
-  ```
-
-  Many thanks to [gilice](https://git.lix.systems/gilice) for this.
-
-- Flakes follow `--eval-system` where it makes sense [fj#673](https://git.lix.systems/lix-project/lix/issues/673) [fj#692](https://git.lix.systems/lix-project/lix/issues/692) [gh#11359](https://github.com/NixOS/nix/issues/11359) [cl/2657](https://gerrit.lix.systems/c/lix/+/2657)
-
-  Most flake commands now follow `--eval-system` when choosing attributes to build/evaluate/etc.
-
-  The exceptions are commands that actually run something on the local machine:
-  - nix develop
-  - nix run
-  - nix upgrade-nix
-  - nix fmt
-  - nix bundle
-
-  This is not a principled approach to cross compilation or anything, flakes still impede rather than support cross compilation, but this unbreaks many remote build use cases.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Remove some gremlins from path garbage collection [fj#621](https://git.lix.systems/lix-project/lix/issues/621) [fj#524](https://git.lix.systems/lix-project/lix/issues/524) [cl/2465](https://gerrit.lix.systems/c/lix/+/2465) [cl/2387](https://gerrit.lix.systems/c/lix/+/2387)
-
-  Path garbage collection had some known unsoundness issues where it would delete things improperly and cause desynchronization between the filesystem state and the database state.
-  Now Lix tolerates better if such a condition exists by not failing the entire GC if a path fails to delete.
-  We also fixed a bug in our file locking implementation that is one possible root cause, but may not be every root cause.
-
-  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) and [Raito Bezarius](https://git.lix.systems/raito) for this.
-
-- Show illegal path references in fixed-outputs derivations [fj#530](https://git.lix.systems/lix-project/lix/issues/530) [cl/2726](https://gerrit.lix.systems/c/lix/+/2726)
-
-  The error created when referencing a store path in a Fixed-Output Derivation is now more verbose, listing the offending paths.
-  This allows for better pinpointing where the issue might be.
-
-  An offender is the following derivation:
-
-  ```nix
-  pkgs.stdenv.mkDerivation {
-    name = "illegal-fod";
-
-    dontUnpack = true;
-    dontBuild = true;
-
-    installPhase = ''
-      cp -R ${pkgs.hello} $out
-    '';
-
-    outputHashMode = "recursive";
-    outputHashAlgo = "sha256";
-    outputHash = pkgs.lib.fakeHash;
-  }
-  ```
-
-  The previous error shown would have been:
-
-  ```
-  error: illegal path references in fixed-output derivation '/nix/store/rpq4m1y79s2nhs1hj7k47yiyykxykiqa-illegal-fod.drv'
-  ```
-
-  and is now:
-
-  ```
-  error: the fixed-output derivation '/nix/store/rpq4m1y79s2nhs1hj7k47yiyykxykiqa-illegal-fod.drv' must not reference store paths but 2 such references were found:
-           /nix/store/1q8w6gl1ll0mwfkqc3c2yx005s6wwfrl-hello-2.12.1
-           /nix/store/wn7v2vhyyyi6clcyn0s9ixvl7d4d87ic-glibc-2.40-36
-  ```
-
-  Many thanks to [Tom Hubrecht](https://git.lix.systems/tom-hubrecht) for this.
-
-- Show error when item from NIX_PATH cannot be downloaded
-
-  For e.g. `nix-instantiate -I https://example.com/404`, you'd only get a warning if the download failed, such as
-
-      warning: Nix search path entry 'https://example.com/404' cannot be downloaded, ignoring
-
-  Now, the full error that caused the download failure is displayed with a note that the search
-  path entry is ignored, e.g.
-
-      warning:
-           … while downloading https://example.com/404 to satisfy NIX_PATH lookup, ignoring search path entry
-
-           warning: unable to download 'https://example.com/404': HTTP error 404 ()
-
-           response body: […]
-
-  Many thanks to [ma27](https://git.lix.systems/ma27) for this.
-
-- Fix Lix crashing on invalid json [fj#642](https://git.lix.systems/lix-project/lix/issues/642) [fj#753](https://git.lix.systems/lix-project/lix/issues/753) [fj#759](https://git.lix.systems/lix-project/lix/issues/759) [fj#769](https://git.lix.systems/lix-project/lix/issues/769) [cl/2907](https://gerrit.lix.systems/c/lix/+/2907)
-
-  Lix no longer crashes when it receives invalid JSON. Instead it'll point to the syntax error and give some context about what happened, for example
-
-  ```
-  ❯ nix derivation add <<<"""
-  error:
-         … while parsing a derivation from stdin
-
-         error: failed to parse JSON: [json.exception.parse_error.101] parse error at line 2, column 1: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literal
-  ```
-
-  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-- Fix handling of `lastModified` in tarball inputs [cl/2792](https://gerrit.lix.systems/c/lix/+/2792)
-
-  Previous versions of Lix would fail with the following error, if a
-  [tarball flake input](@docroot@/protocols/tarball-fetcher.md) redirect
-  to a URL that contains a `lastModified` field:
-
-  ```
-  error: input attribute 'lastModified' is not an integer
-  ```
-
-  This is now fixed.
-
-  Many thanks to [xanderio](https://github.com/xanderio) and [Julian Stecklina](https://github.com/blitz) for this.
-
-- Fix `--debugger --ignore-try` [cl/2440](https://gerrit.lix.systems/c/lix/+/2440)
-
-  When in debug mode (e.g. from using the `--debugger` flag), enabling [`ignore-try`](@docroot@/command-ref/conf-file.md#conf-ignore-try) once again properly disables debug REPLs within [`builtins.tryEval`](@docroot@/language/builtins.md#builtins-tryEval) calls. Previously, a debug REPL would be started as if `ignore-try` was disabled, but that REPL wouldn't actually be in debug mode, and upon exiting the REPL the evaluating process would segfault.
-
-  Many thanks to [Dusk Banks](https://git.lix.systems/bb010g) for this.
-
-- Don't consider a path with a specified rev to be `locked` [cl/2064](https://gerrit.lix.systems/c/lix/+/2064)
-
-  Until now it was allowed to do e.g.
-
-      $ echo 'lalala' > testfile
-      $ nix eval --expr '(builtins.fetchTree { path = "/home/ma27/testfile"; rev = "0000000000000000000000000000000000000000"; type = "path"; })'
-      { lastModified = 1723656303; lastModifiedDate = "20240814172503"; narHash = "sha256-hOMY06A0ohaaCLwnhpZIMoAqi/8kG2vk30NRiqi0dfc="; outPath = "/nix/store/lhfz259iipmv9ky995rml8018jvriynh-source"; rev = "0000000000000000000000000000000000000000"; shortRev = "0000000"; }
-      $ cat /nix/store/lhfz259iipmv9ky995rml8018jvriynh-source
-      lalala
-
-  because any kind of input with a `rev` specified is considered to be locked.
-
-  With this change, inputs of type `path`, `indirect` and `tarball` are no longer
-  considered locked with a rev, but no hash specified.
-
-  This behavior was changed in
-  [CppNix 2.21 as well](https://github.com/nixos/nix/commit/071dd2b3a4e6c0b2106f1b6f14ec26e153d97446) as well.
-
-  Many thanks to [ma27](https://git.lix.systems/ma27) for this.
-
-- Fix macOS sandbox profile size errors [fj#752](https://git.lix.systems/lix-project/lix/issues/752) [fj#718](https://git.lix.systems/lix-project/lix/issues/718) [cl/2861](https://gerrit.lix.systems/c/lix/+/2861)
-
-  Fixed an issue on macOS where the sandbox profile could exceed size limits when building derivations with many dependencies. The profile is now split into multiple allowed sections to stay under the interpreter's limits.
-
-  This resolves errors like
-
-  ```
-  error: (failed with exit code 1, previous messages: sandbox initialization failed: data object length 65730 exceeds maximum (65535)|failed to configure sandbox)
-
-         error: unexpected EOF reading a line
-  ```
-
-  Many thanks to [Pierre-Etienne Meunier](https://github.com/P-E-Meunier) and [Poliorcetics](https://github.com/poliorcetics) for this.
-
-- Fix interference of the multiline progress bar with output [cl/2774](https://gerrit.lix.systems/c/lix/+/2774)
-
-  In some situations, the progress indicator of the multiline progress bar would interfere with persistent output.
-  This would result in progress bar headers being visible in place of the desired text, for example the outputs shown after a `:b` command in the repl.
-  The underlying ordering issue has been fixed, so that the undesired interference does not happen any more.
-
-  Many thanks to [alois31](https://git.lix.systems/alois31) for this.
-
-- Paralellise `nix store sign` using a thread pool [fj#399](https://git.lix.systems/lix-project/lix/issues/399) [cl/2606](https://gerrit.lix.systems/c/lix/+/2606)
-
-  `nix store sign` with a large collection of provided paths (such as when using with `--all`) has historically
-  signed these paths serially. Taking extreme amounts of time when preforming operations such as fixing binary
-  caches. This has been changed. Now these signatures are performed using a thread pool like `nix store copy-sigs`.
-
-  Many thanks to [Lunaphied](https://git.lix.systems/Lunaphied) for this.
-
-- `post-build-hook` only receives settings that are set [fj#739](https://git.lix.systems/lix-project/lix/issues/739) [cl/2800](https://gerrit.lix.systems/c/lix/+/2800)
-
-  If one is using `post-build-hook` to upload paths to a cache, it used to be broken if CppNix was used inside the script, since CppNix would fail about unsupported configuration option values in some of Lix's defaults.
-  This is because `post-build-hook` receives the settings of the nix daemon in the `NIX_CONFIG` environment variable.
-  Now Lix only emits overridden settings to `post-build-hook` invocations, which fixes this issue in the majority of cases: where the configuration is not explicitly incompatible.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-- Remove lix-initiated ssh connection sharing [fj#304](https://git.lix.systems/lix-project/lix/issues/304) [fj#644](https://git.lix.systems/lix-project/lix/issues/644) [cl/3005](https://gerrit.lix.systems/c/lix/+/3005)
-
-  Lix no longer explicitly requests ssh connection sharing (ControlMaster/ControlPath SSH
-  options, see also ssh_config(5) man page) when connecting to remote stores.  This may
-  impact command latency when `NIX_REMOTE` is set to a `ssh://` or `ssh-ng://` url, or if
-  `--store` is specified. Remote build connections did not use ssh connection sharing.
-
-  Connection sharing configuration is now inherited from user configuration at all times. It
-  is now advisable to configure connection sharing for remote builders for improved latency.
-
-  Many thanks to [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-
-## Development
-
-- Add `nix_plugin_entry` entry point for plugins [fj#740](https://git.lix.systems/lix-project/lix/issues/740) [fj#359](https://git.lix.systems/lix-project/lix/issues/359) [gh#8699](https://github.com/NixOS/nix/pull/8699) [cl/2826](https://gerrit.lix.systems/c/lix/+/2826)
-
-  Plugins are an exceptionally rarely used feature in Lix, but they are important as a prototyping tool for code destined for Lix itself, and we want to keep supporting them as a low-maintenance-cost feature.
-  As part of the overall move towards getting rid of static initializers for stability and predictability reasons, we added an explicit `nix_plugin_entry` function like CppNix has, which is called immediately after plugin load, if present.
-  This makes control flow more explicit and allows for easily registering things that have had their static initializer registration classes removed.
-
-  Many thanks to [jade](https://git.lix.systems/jade) and [yorickvp](https://github.com/yorickvp) for this.
-
-
-## Miscellany
-
-- Set default of `connect-timeout` to `5` [cl/2799](https://gerrit.lix.systems/c/lix/+/2799)
-
-  By default, the connection timeout to substituters is now 5s instead of 300s.
-  That way, unavailable substituters are detected quicker.
-
-  Many thanks to [ma27](https://git.lix.systems/ma27) for this.

doc/manual/substitute.py

@@ -1,21 +1,9 @@
 #!/usr/bin/env python3
-"""
-Preprocesses mdbook markdown, primarily for include directives.
-
-The include directive format is as follows:
-    {{#include foo/bar/baz.md}}
-
-The content of includes will be indented as much as the directive itself.
-
-Including a generated file (from building Lix; generally for the 'new' CLI):
-    {{#include @generated@/foo/bar/baz.md}}
-"""
 
 from pathlib import Path
 import json
 import os, os.path
 import sys
-import textwrap
 
 name = 'substitute.py'
 
@@ -23,12 +11,6 @@ def log(*args, **kwargs):
     kwargs['file'] = sys.stderr
     return print(f'{name}:', *args, **kwargs)
 
-def remove_prefix_if_present(s: str, prefix: str) -> str | None:
-    if s.startswith(prefix):
-        return s.removeprefix(prefix)
-    else:
-        return None
-
 def do_include(content: str, relative_md_path: Path, source_root: Path, search_path: Path):
     assert not relative_md_path.is_absolute(), f'{relative_md_path=} from mdbook should be relative'
 
@@ -38,32 +20,16 @@ def do_include(content: str, relative_md_path: Path, source_root: Path, search_p
 
     lines = []
     for l in content.splitlines(keepends=True):
-        if remain := remove_prefix_if_present(l.strip(), "{{#include"):
-            requested = remain[1:-2]
-            # We indent bodies of indent directives by the indent of the
-            # directive itself.
-            num_leading_indent = len(l) - len(l.lstrip())
-
-            if subpath := remove_prefix_if_present(requested, "@generated@/"):
-                included = search_path / Path(subpath)
+        if l.strip().startswith("{{#include "):
+            requested = l.strip()[11:][:-2]
+            if requested.startswith("@generated@/"):
+                included = search_path / Path(requested[12:])
                 requested = included.relative_to(search_path)
             else:
                 included = source_root / relative_md_path.parent / requested
                 requested = included.resolve().relative_to(source_root)
             assert included.exists(), f"{requested} not found at {included}"
-
-            lines.append(
-                textwrap.indent(
-                    do_include(
-                        included.read_text(),
-                        requested,
-                        source_root,
-                        search_path,
-                    ),
-                    " " * num_leading_indent
-                )
-                + "\n"
-            )
+            lines.append(do_include(included.read_text(), requested, source_root, search_path) + "\n")
         else:
             lines.append(l)
     return "".join(lines)

docker.nix

@@ -157,7 +157,7 @@ let
 
   nixConfContents =
     (lib.concatStringsSep "\n" (
-      lib.mapAttrsToList (
+      lib.mapAttrsFlatten (
         n: v:
         let
           vStr = if builtins.isList v then lib.concatStringsSep " " v else v;

flake.nix

@@ -36,7 +36,6 @@
       sgr = builtins.fromJSON ''"\u001b["'';
       freezePage = "https://wiki.lix.systems/books/lix-contributors/page/freezes-and-recommended-contributions";
       codebaseOverview = "https://wiki.lix.systems/books/lix-contributors/page/codebase-overview";
-      gerritWiki = "https://wiki.lix.systems/books/lix-contributors/page/gerrit";
       contribNotice = builtins.toFile "lix-contrib-notice" ''
         Hey there!
 
@@ -54,10 +53,6 @@
         and we'd like to work together with all contributors as much as possible.
         Lix is a collaborative project :)
 
-        If you want to submit a patch and you never used gerrit before, please
-        check our gerrit wiki section:
-          ${sgr}32m${gerritWiki}${sgr}0m
-
         You can open an issue at https://git.lix.systems/lix-project/lix/issues
         or chat with us on Matrix: #space:lix.systems.
 
@@ -97,7 +92,8 @@
         "armv7l-linux"
         "riscv64-linux"
         "aarch64-linux"
-        "x86_64-freebsd"
+        # FIXME: still broken in 24.05: fails to build rustc(??) due to missing -lstdc++ dep
+        # "x86_64-freebsd"
         # FIXME: broken dev shell due to python
         # "x86_64-netbsd"
       ];
@@ -201,21 +197,6 @@
 
           lix-clang-tidy = final.callPackage ./subprojects/lix-clang-tidy { };
 
-          nix-eval-jobs = final.callPackage ./subprojects/nix-eval-jobs {
-            srcDir = ./subprojects/nix-eval-jobs;
-          };
-
-          # HACK: We need nix-prefetch-git for fetchCargoVendor for Rust stuff,
-          # so it can't use Lix, or we infrec:
-          #   lix -> Rust stuff -> fetchCargoVendor -> nix-prefetch-git -> nix (lix)
-          # This will eventually become a problem upstream, but until then,
-          # apply some duct tape and pray.
-          nix-prefetch-git =
-            if (lib.functionArgs prev.nix-prefetch-git.override) ? "nix" then
-              prev.nix-prefetch-git.override { nix = prev.nix; }
-            else
-              prev.nix-prefetch-git;
-
           # Export the patched version of boehmgc that Lix uses into the overlay
           # for consumers of this flake.
           boehmgc-nix = final.nix.passthru.boehmgc-nix;
@@ -265,9 +246,6 @@
         # Perl bindings for various platforms.
         perlBindings = forAllSystems (system: nixpkgsFor.${system}.native.nix.passthru.perl-bindings);
 
-        # nix-eval-jobs can be built against this Lix.
-        nix-eval-jobs = forAllSystems (system: nixpkgsFor.${system}.native.nix-eval-jobs);
-
         # Binary tarball for various platforms, containing a Nix store
         # with the closure of 'nix' package.
         binaryTarball = forAllSystems (system: nixpkgsFor.${system}.native.nix.passthru.binaryTarball);
@@ -299,98 +277,87 @@
           });
 
         # System tests.
-        tests =
-          import ./tests/nixos {
-            inherit
-              self
-              lib
-              nixpkgs
-              nixpkgsFor
-              ;
-          }
-          // {
-            nix-eval-jobs = forAllSystems (system: self.packages.${system}.nix-eval-jobs.tests.nix-eval-jobs);
+        tests = import ./tests/nixos { inherit lib nixpkgs nixpkgsFor; } // {
+          # This is x86_64-linux only, just because we have significantly
+          # cheaper x86_64-linux compute in CI.
+          # It is clangStdenv because clang's sanitizers are nicer.
+          asanBuild = self.packages.x86_64-linux.nix-clangStdenv.override {
+            # Improve caching of non-code changes by not changing the
+            # derivation name every single time, since this will never be seen
+            # by users anyway.
+            versionSuffix = "";
+            sanitize = [
+              "address"
+              "undefined"
+            ];
+            # it is very hard to make *every* CI build use this option such
+            # that we don't wind up building Lix twice, so we do it here where
+            # we are already doing so.
+            werror = true;
+          };
 
-            # This is x86_64-linux only, just because we have significantly
-            # cheaper x86_64-linux compute in CI.
-            # It is clangStdenv because clang's sanitizers are nicer.
-            asanBuild = self.packages.x86_64-linux.nix-clangStdenv.override {
-              # Improve caching of non-code changes by not changing the
-              # derivation name every single time, since this will never be seen
-              # by users anyway.
+          # Although this might be nicer to do with pre-commit, that would
+          # require adding 12MB of nodejs to the dev shell, whereas building it
+          # in CI with Nix avoids that at a cost of slower feedback on rarely
+          # touched files.
+          jsSyntaxCheck =
+            let
+              nixpkgs = nixpkgsFor.x86_64-linux.native;
+              inherit (nixpkgs) pkgs;
+              docSources = lib.fileset.toSource {
+                root = ./doc;
+                fileset = lib.fileset.fileFilter (f: f.hasExt "js") ./doc;
+              };
+            in
+            pkgs.runCommand "js-syntax-check" { } ''
+              find ${docSources} -type f -print -exec ${pkgs.nodejs-slim}/bin/node --check '{}' ';'
+              touch $out
+            '';
+
+          # clang-tidy run against the Lix codebase using the Lix clang-tidy plugin
+          clang-tidy =
+            let
+              nixpkgs = nixpkgsFor.x86_64-linux.native;
+              inherit (nixpkgs) pkgs;
+            in
+            pkgs.callPackage ./package.nix {
+              # Required since we don't support gcc stdenv
+              stdenv = pkgs.clangStdenv;
               versionSuffix = "";
-              sanitize = [
-                "address"
-                "undefined"
-              ];
-              # it is very hard to make *every* CI build use this option such
-              # that we don't wind up building Lix twice, so we do it here where
-              # we are already doing so.
-              werror = true;
+              lintInsteadOfBuild = true;
             };
 
-            # Although this might be nicer to do with pre-commit, that would
-            # require adding 12MB of nodejs to the dev shell, whereas building it
-            # in CI with Nix avoids that at a cost of slower feedback on rarely
-            # touched files.
-            jsSyntaxCheck =
-              let
-                nixpkgs = nixpkgsFor.x86_64-linux.native;
-                inherit (nixpkgs) pkgs;
-                docSources = lib.fileset.toSource {
-                  root = ./doc;
-                  fileset = lib.fileset.fileFilter (f: f.hasExt "js") ./doc;
-                };
-              in
-              pkgs.runCommand "js-syntax-check" { } ''
-                find ${docSources} -type f -print -exec ${pkgs.nodejs-slim}/bin/node --check '{}' ';'
-                touch $out
-              '';
+          # Make sure that nix-env still produces the exact same result
+          # on a particular version of Nixpkgs.
+          evalNixpkgs =
+            with nixpkgsFor.x86_64-linux.native;
+            runCommand "eval-nixos" { buildInputs = [ nix ]; } ''
+              type -p nix-env
+              # Note: we're filtering out nixos-install-tools because https://github.com/NixOS/nixpkgs/pull/153594#issuecomment-1020530593.
+              time nix-env --store dummy:// -f ${nixpkgs-regression} -qaP --drv-path | sort | grep -v nixos-install-tools > packages
+              [[ $(sha1sum < packages | cut -c1-40) = 402242fca90874112b34718b8199d844e8b03d12 ]]
+              mkdir $out
+            '';
 
-            # clang-tidy run against the Lix codebase using the Lix clang-tidy plugin
-            clang-tidy =
-              let
-                nixpkgs = nixpkgsFor.x86_64-linux.native;
-                inherit (nixpkgs) pkgs;
-              in
-              pkgs.callPackage ./package.nix {
-                # Required since we don't support gcc stdenv
-                stdenv = pkgs.clangStdenv;
-                versionSuffix = "";
-                lintInsteadOfBuild = true;
-              };
-
-            # Make sure that nix-env still produces the exact same result
-            # on a particular version of Nixpkgs.
-            evalNixpkgs =
-              with nixpkgsFor.x86_64-linux.native;
-              runCommand "eval-nixos" { buildInputs = [ nix ]; } ''
-                type -p nix-env
-                # Note: we're filtering out nixos-install-tools because https://github.com/NixOS/nixpkgs/pull/153594#issuecomment-1020530593.
-                time nix-env --store dummy:// -f ${nixpkgs-regression} -qaP --drv-path | sort | grep -v nixos-install-tools > packages
-                [[ $(sha1sum < packages | cut -c1-40) = 402242fca90874112b34718b8199d844e8b03d12 ]]
-                mkdir $out
-              '';
-
-            nixpkgsLibTests = forAllSystems (
-              system:
-              let
-                inherit (self.packages.${system}) nix;
-                pkgs = nixpkgsFor.${system}.native;
-                testWithNix = import (nixpkgs + "/lib/tests/test-with-nix.nix") { inherit pkgs lib nix; };
-              in
-              pkgs.symlinkJoin {
-                name = "nixpkgs-lib-tests";
-                paths =
-                  [ testWithNix ]
-                  # NOTE: nixpkgs 24.11 is being ... *creative*, and requires this dance to override
-                  # the evaluator used for the test. it will break again in the future, don't worry.
-                  ++ lib.optionals pkgs.stdenv.isLinux [
-                    (pkgs.callPackage "${nixpkgs}/ci/eval" { nixVersions.nix_2_24 = nix; }).attrpathsSuperset
-                  ];
-              }
-            );
-          };
+          nixpkgsLibTests = forAllSystems (
+            system:
+            let
+              inherit (self.packages.${system}) nix;
+              pkgs = nixpkgsFor.${system}.native;
+              testWithNix = import (nixpkgs + "/lib/tests/test-with-nix.nix") { inherit pkgs lib nix; };
+            in
+            pkgs.symlinkJoin {
+              name = "nixpkgs-lib-tests";
+              paths =
+                [ testWithNix ]
+                # NOTE: nixpkgs 24.11 is being ... *creative*, and requires this dance to override
+                # the evaluator used for the test. it will break again in the future, don't worry.
+                ++ lib.optionals pkgs.stdenv.isLinux [
+                  (pkgs.callPackage "${nixpkgs}/ci/eval" { nixVersions.nix_2_24 = nix; }).attrpathsSuperset
+                ];
+            }
+          );
+        };
 
         pre-commit = forAvailableSystems (
           system:
@@ -438,7 +405,6 @@
 
           binaryTarball = self.hydraJobs.binaryTarball.${system};
           perlBindings = self.hydraJobs.perlBindings.${system};
-          nix-eval-jobs = self.hydraJobs.nix-eval-jobs.${system};
           nixpkgsLibTests = self.hydraJobs.tests.nixpkgsLibTests.${system};
           rl-next = self.hydraJobs.rl-next.${system}.user;
           # Will be empty attr set on i686-linux, and filtered out by forAvailableSystems.
@@ -456,7 +422,7 @@
           inherit (nixpkgsFor.${system}.native) nix;
           default = nix;
 
-          inherit (nixpkgsFor.${system}.native) lix-clang-tidy nix-eval-jobs;
+          inherit (nixpkgsFor.${system}.native) lix-clang-tidy;
         }
         // (
           lib.optionalAttrs (builtins.elem system linux64BitSystems) {

justfile

@@ -8,47 +8,30 @@ list:
 clean:
     rm -rf build
 
-# Prepare meson for building with extra options
-setup-custom *OPTIONS:
+# Prepare meson for building
+setup *OPTIONS:
     meson setup build --prefix="$PWD/outputs/out" $mesonFlags {{ OPTIONS }}
 
-# Prepare meson for building
-setup: (setup-custom)
-
-# Build lix with extra options
-build-custom *OPTIONS:
-    meson compile -C build {{ OPTIONS }}
-
 # Build lix
-build: (build-custom)
+build *OPTIONS:
+    meson compile -C build {{ OPTIONS }}
 
 alias compile := build
 
-# Install lix for local development with extra options
-install-custom *OPTIONS: (build-custom OPTIONS)
+# Install lix for local development
+install *OPTIONS: (build OPTIONS)
     meson install -C build
 
-# Install lix for local development
-install: (install-custom)
-
-# Run tests (usually requires `install`) with extra options
+# Run tests
 test *OPTIONS:
     meson test -C build --print-errorlogs {{ OPTIONS }}
 
-# Run unit tests only
-test-unit *OPTIONS: (test "--suite" "check")
-
-# Run integration tests only
-test-integration *OPTIONS: install (test "--suite" "installcheck")
-
 alias clang-tidy := lint
 
-# Lint with `clang-tidy`
 lint:
     ninja -C build clang-tidy
 
 alias clang-tidy-fix := lint-fix
 
-# Fix lints with `clang-tidy-fix`
 lint-fix:
     ninja -C build clang-tidy-fix

lix/legacy/build-remote.cc

@@ -53,7 +53,7 @@ static bool allSupportedLocally(Store & store, const std::set<std::string>& requ
     return true;
 }
 
-static int main_build_remote(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_build_remote(std::string programName, Strings argv)
 {
     {
         logger = makeJSONLogger(*logger);
@@ -84,12 +84,12 @@ static int main_build_remote(AsyncIoRoot & aio, std::string programName, Strings
 
         initPlugins();
 
-        auto store = aio.blockOn(openStore());
+        auto store = openStore();
 
         /* It would be more appropriate to use $XDG_RUNTIME_DIR, since
            that gets cleared on reboot, but it wouldn't work on macOS. */
         auto currentLoadName = "/current-load";
-        if (auto localStore = store.try_cast_shared<LocalFSStore>())
+        if (auto localStore = store.dynamic_pointer_cast<LocalFSStore>())
             currentLoad = std::string { localStore->config().stateDir } + currentLoadName;
         else
             currentLoad = settings.nixStateDir + currentLoadName;
@@ -243,11 +243,11 @@ static int main_build_remote(AsyncIoRoot & aio, std::string programName, Strings
 
                     Activity act(*logger, lvlTalkative, actUnknown, fmt("connecting to '%s'", bestMachine->storeUri));
 
-                    sshStore = aio.blockOn(bestMachine->openStore());
-                    aio.blockOn(sshStore->connect());
+                    sshStore = bestMachine->openStore();
+                    sshStore->connect();
                     storeUri = bestMachine->storeUri;
 
-                } catch (std::exception & e) { // NOLINT(lix-foreign-exceptions)
+                } catch (std::exception & e) {
                     auto msg = chomp(drainFD(5, false));
                     printError("cannot build on '%s': %s%s",
                         bestMachine->storeUri, e.what(),
@@ -285,19 +285,12 @@ connected:
 
         {
             Activity act(*logger, lvlTalkative, actUnknown, fmt("copying dependencies to '%s'", storeUri));
-            aio.blockOn(copyPaths(
-                *store,
-                *sshStore,
-                store->parseStorePathSet(inputs),
-                NoRepair,
-                NoCheckSigs,
-                substitute
-            ));
+            copyPaths(*store, *sshStore, store->parseStorePathSet(inputs), NoRepair, NoCheckSigs, substitute);
         }
 
         uploadLock.reset();
 
-        auto drv = aio.blockOn(store->readDerivation(*drvPath));
+        auto drv = store->readDerivation(*drvPath);
 
         std::optional<BuildResult> optResult;
 
@@ -305,7 +298,7 @@ connected:
         // stores), we assume we are. This is necessary for backwards
         // compat.
         bool trustedOrLegacy = ({
-            std::optional trusted = aio.blockOn(sshStore->isTrustedClient());
+            std::optional trusted = sshStore->isTrustedClient();
             !trusted || *trusted;
         });
 
@@ -324,51 +317,74 @@ connected:
             //
             // 2. Changing the `inputSrcs` set changes the associated
             //    output ids, which break CA derivations
-            if (!drv.inputDrvs.empty())
+            if (!drv.inputDrvs.map.empty())
                 drv.inputSrcs = store->parseStorePathSet(inputs);
-            optResult = aio.blockOn(sshStore->buildDerivation(*drvPath, (const BasicDerivation &) drv));
+            optResult = sshStore->buildDerivation(*drvPath, (const BasicDerivation &) drv);
             auto & result = *optResult;
             if (!result.success())
                 throw Error("build of '%s' on '%s' failed: %s", store->printStorePath(*drvPath), storeUri, result.errorMsg);
         } else {
-            aio.blockOn(copyClosure(
-                *store, *sshStore, StorePathSet{*drvPath}, NoRepair, NoCheckSigs, substitute
-            ));
-            auto res = aio.blockOn(sshStore->buildPathsWithResults({
+            copyClosure(*store, *sshStore, StorePathSet {*drvPath}, NoRepair, NoCheckSigs, substitute);
+            auto res = sshStore->buildPathsWithResults({
                 DerivedPath::Built {
-                    .drvPath = makeConstantStorePath(*drvPath),
+                    .drvPath = makeConstantStorePathRef(*drvPath),
                     .outputs = OutputsSpec::All {},
                 }
-            }));
+            });
             // One path to build should produce exactly one build result
             assert(res.size() == 1);
             optResult = std::move(res[0]);
         }
 
 
+        auto outputHashes = staticOutputHashes(*store, drv);
+        std::set<Realisation> missingRealisations;
         StorePathSet missingPaths;
-        auto outputPaths = drv.outputsAndPaths(*store);
-        for (auto & [outputName, outputPath] : outputPaths) {
-            if (!aio.blockOn(store->isValidPath(outputPath.second)))
-                missingPaths.insert(outputPath.second);
+        if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations) && !drv.type().hasKnownOutputPaths()) {
+            for (auto & outputName : wantedOutputs) {
+                auto thisOutputHash = outputHashes.at(outputName);
+                auto thisOutputId = DrvOutput{ thisOutputHash, outputName };
+                if (!store->queryRealisation(thisOutputId)) {
+                    debug("missing output %s", outputName);
+                    assert(optResult);
+                    auto & result = *optResult;
+                    auto i = result.builtOutputs.find(outputName);
+                    assert(i != result.builtOutputs.end());
+                    auto & newRealisation = i->second;
+                    missingRealisations.insert(newRealisation);
+                    missingPaths.insert(newRealisation.outPath);
+                }
+            }
+        } else {
+            auto outputPaths = drv.outputsAndOptPaths(*store);
+            for (auto & [outputName, hopefullyOutputPath] : outputPaths) {
+                assert(hopefullyOutputPath.second);
+                if (!store->isValidPath(*hopefullyOutputPath.second))
+                    missingPaths.insert(*hopefullyOutputPath.second);
+            }
         }
 
         if (!missingPaths.empty()) {
             Activity act(*logger, lvlTalkative, actUnknown, fmt("copying outputs from '%s'", storeUri));
-            if (auto localStore = store.try_cast_shared<LocalStore>())
+            if (auto localStore = store.dynamic_pointer_cast<LocalStore>())
                 for (auto & path : missingPaths)
                     localStore->locksHeld.insert(store->printStorePath(path)); /* FIXME: ugly */
-            aio.blockOn(
-                copyPaths(*sshStore, *store, missingPaths, NoRepair, NoCheckSigs, NoSubstitute)
-            );
+            copyPaths(*sshStore, *store, missingPaths, NoRepair, NoCheckSigs, NoSubstitute);
+        }
+        // XXX: Should be done as part of `copyPaths`
+        for (auto & realisation : missingRealisations) {
+            // Should hold, because if the feature isn't enabled the set
+            // of missing realisations should be empty
+            experimentalFeatureSettings.require(Xp::CaDerivations);
+            store->registerDrvOutput(realisation);
         }
 
         return 0;
     }
 }
 
-void registerLegacyBuildRemote() {
-    LegacyCommandRegistry::add("build-remote", main_build_remote);
+void registerBuildRemote() {
+    LegacyCommands::add("build-remote", main_build_remote);
 }
 
 }

lix/legacy/build-remote.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyBuildRemote();
+void registerBuildRemote();
 
 }

lix/legacy/dotgraph.cc

@@ -1,7 +1,5 @@
 #include "dotgraph.hh"
 #include "lix/libstore/store-api.hh"
-#include "lix/libutil/async.hh"
-#include "lix/libutil/result.hh"
 
 #include <iostream>
 
@@ -43,8 +41,8 @@ static std::string makeNode(std::string_view id, std::string_view label,
 }
 
 
-kj::Promise<Result<void>> printDotGraph(ref<Store> store, StorePathSet && roots)
-try {
+void printDotGraph(ref<Store> store, StorePathSet && roots)
+{
     StorePathSet workList(std::move(roots));
     StorePathSet doneSet;
 
@@ -57,7 +55,7 @@ try {
 
         cout << makeNode(std::string(path.to_string()), path.name(), "#ff0000");
 
-        for (auto & p : TRY_AWAIT(store->queryPathInfo(path))->references) {
+        for (auto & p : store->queryPathInfo(path)->references) {
             if (p != path) {
                 workList.insert(p);
                 cout << makeEdge(std::string(p.to_string()), std::string(path.to_string()));
@@ -66,9 +64,6 @@ try {
     }
 
     cout << "}\n";
-    co_return result::success();
-} catch (...) {
-    co_return result::current_exception();
 }
 
 

lix/legacy/dotgraph.hh

@@ -5,6 +5,6 @@
 
 namespace nix {
 
-kj::Promise<Result<void>> printDotGraph(ref<Store> store, StorePathSet && roots);
+void printDotGraph(ref<Store> store, StorePathSet && roots);
 
 }

lix/legacy/graphml.cc

@@ -1,8 +1,6 @@
 #include "graphml.hh"
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/derivations.hh"
-#include "lix/libutil/async.hh"
-#include "lix/libutil/result.hh"
 
 #include <iostream>
 
@@ -48,8 +46,8 @@ static std::string makeNode(const ValidPathInfo & info)
 }
 
 
-kj::Promise<Result<void>> printGraphML(ref<Store> store, StorePathSet && roots)
-try {
+void printGraphML(ref<Store> store, StorePathSet && roots)
+{
     StorePathSet workList(std::move(roots));
     StorePathSet doneSet;
     std::pair<StorePathSet::iterator, bool> ret;
@@ -69,7 +67,7 @@ try {
         ret = doneSet.insert(path);
         if (ret.second == false) continue;
 
-        auto info = TRY_AWAIT(store->queryPathInfo(path));
+        auto info = store->queryPathInfo(path);
         cout << makeNode(*info);
 
         for (auto & p : info->references) {
@@ -83,9 +81,6 @@ try {
 
     cout << "</graph>\n";
     cout << "</graphml>\n";
-    co_return result::success();
-} catch (...) {
-    co_return result::current_exception();
 }
 
 

lix/legacy/graphml.hh

@@ -5,6 +5,6 @@
 
 namespace nix {
 
-kj::Promise<Result<void>> printGraphML(ref<Store> store, StorePathSet && roots);
+void printGraphML(ref<Store> store, StorePathSet && roots);
 
 }

lix/legacy/nix-build.cc

@@ -1,10 +1,14 @@
 #include <cstring>
+#include <fstream>
 #include <iostream>
+#include <filesystem>
 #include <regex>
 #include <sstream>
 #include <vector>
 #include <map>
 
+#include <nlohmann/json.hpp>
+
 #include "lix/libstore/parsed-derivations.hh"
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/local-fs-store.hh"
@@ -14,11 +18,11 @@
 #include "lix/libmain/shared.hh"
 #include "lix/libstore/path-with-outputs.hh"
 #include "lix/libexpr/eval.hh"
+#include "lix/libexpr/eval-inline.hh"
 #include "lix/libexpr/get-drvs.hh"
 #include "lix/libcmd/common-eval-args.hh"
 #include "lix/libexpr/attr-path.hh"
 #include "lix/libcmd/legacy.hh"
-#include "lix/libutil/regex.hh"
 #include "lix/libutil/shlex.hh"
 #include "nix-build.hh"
 #include "lix/libstore/temporary-dir.hh"
@@ -29,10 +33,10 @@ namespace nix {
 
 using namespace std::string_literals;
 
-static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings argv)
+static void main_nix_build(std::string programName, Strings argv)
 {
     auto dryRun = false;
-    auto runEnv = std::regex_search(programName, regex::parse("nix-shell$"));
+    auto runEnv = std::regex_search(programName, std::regex("nix-shell$"));
     auto pure = false;
     auto fromArgs = false;
     auto packages = false;
@@ -69,7 +73,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
         script = argv.front();
         try {
             auto lines = tokenizeString<Strings>(readFile(script), "\n");
-            if (std::regex_search(lines.front(), regex::parse("^#!"))) {
+            if (std::regex_search(lines.front(), std::regex("^#!"))) {
                 lines.pop_front();
                 inShebang = true;
                 savedArgs = {std::next(argv.begin()), argv.end()};
@@ -77,7 +81,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
                 for (auto line : lines) {
                     line = chomp(line);
                     std::smatch match;
-                    if (std::regex_match(line, match, regex::parse("^#!\\s*nix-shell\\s+(.*)$")))
+                    if (std::regex_match(line, match, std::regex("^#!\\s*nix-shell\\s+(.*)$")))
                         for (const auto & word : shell_split(match[1].str()))
                             argv.push_back(word);
                 }
@@ -90,7 +94,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
         using LegacyArgs::LegacyArgs;
     };
 
-    MyArgs myArgs(aio, myName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+    MyArgs myArgs(myName, [&](Strings::iterator & arg, const Strings::iterator & end) {
         if (*arg == "--help") {
             showManPage(myName);
         }
@@ -149,14 +153,14 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
             // executes it unless it contains the string "perl" or "indir",
             // or (undocumented) argv[0] does not contain "perl". Exploit
             // the latter by doing "exec -a".
-            if (std::regex_search(interpreter, regex::parse("perl")))
+            if (std::regex_search(interpreter, std::regex("perl")))
                 execArgs = "-a PERL";
 
             std::ostringstream joined;
             for (const auto & i : savedArgs)
                 joined << shellEscape(i) << ' ';
 
-            if (std::regex_search(interpreter, regex::parse("ruby"))) {
+            if (std::regex_search(interpreter, std::regex("ruby"))) {
                 // Hack for Ruby. Ruby also examines the shebang. It tries to
                 // read the shebang to understand which packages to read from. Since
                 // this is handled via nix-shell -p, we wrap our ruby script execution
@@ -191,12 +195,12 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
     if (outLink.empty())
         outLink = (Path) tmpDir + "/result";
 
-    auto store = aio.blockOn(openStore());
-    auto evalStore = myArgs.evalStoreUrl ? aio.blockOn(openStore(*myArgs.evalStoreUrl)) : store;
+    auto store = openStore();
+    auto evalStore = myArgs.evalStoreUrl ? openStore(*myArgs.evalStoreUrl) : store;
 
-    auto evaluator = std::make_unique<Evaluator>(aio, myArgs.searchPath, evalStore, store);
+    auto evaluator = std::make_unique<Evaluator>(myArgs.searchPath, evalStore, store);
     evaluator->repair = myArgs.repair;
-    auto state = evaluator->begin(aio);
+    auto state = evaluator->begin();
     if (myArgs.repair) buildMode = bmRepair;
 
     auto autoArgs = myArgs.getAutoArgs(*evaluator);
@@ -245,15 +249,15 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
                 } catch (Error & e) {};
                 auto [path, outputNames] = parsePathWithOutputs(absolute);
                 if (evalStore->isStorePath(path) && path.ends_with(".drv"))
-                    drvs.push_back(aio.blockOn(DrvInfo::create(evalStore, absolute)));
+                    drvs.push_back(DrvInfo(evalStore, absolute));
                 else
                     /* If we're in a #! script, interpret filenames
                        relative to the script. */
                     exprs.push_back(evaluator->parseExprFromFile(
-                        evaluator->paths.resolveExprPath(aio.blockOn(lookupFileArg(
+                        evaluator->paths.resolveExprPath(lookupFileArg(
                             *evaluator,
                             inShebang && !packages ? absPath(i, absPath(dirOf(script))) : i
-                        )).unwrap())
+                        ))
                     ));
             }
         }
@@ -271,13 +275,11 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
                 return false;
             }
             bool add = false;
-            if (v.type() == nFunction) {
-                if (auto pattern = dynamic_cast<AttrsPattern *>(v.lambda.fun->pattern.get())) {
-                    for (auto & i : pattern->formals) {
-                        if (evaluator->symbols[i.name] == "inNixShell") {
-                            add = true;
-                            break;
-                        }
+            if (v.type() == nFunction && v.lambda.fun->hasFormals()) {
+                for (auto & i : v.lambda.fun->formals->formals) {
+                    if (evaluator->symbols[i.name] == "inNixShell") {
+                        add = true;
+                        break;
                     }
                 }
             }
@@ -291,7 +293,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
                 takesNixShellAttr(vRoot) ? *autoArgsWithInNixShell : *autoArgs,
                 vRoot
             ).first);
-            state->forceValue(v, noPos);
+            state->forceValue(v, v.determinePos(noPos));
             getDerivations(
                 *state,
                 v,
@@ -310,17 +312,14 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
            fetch binary cache data. */
         uint64_t downloadSize, narSize;
         StorePathSet willBuild, willSubstitute, unknown;
-        aio.blockOn(store->queryMissing(paths,
-            willBuild, willSubstitute, unknown, downloadSize, narSize));
+        store->queryMissing(paths,
+            willBuild, willSubstitute, unknown, downloadSize, narSize);
 
-        if (settings.printMissing) {
-            aio.blockOn(printMissing(
-                ref<Store>(store), willBuild, willSubstitute, unknown, downloadSize, narSize
-            ));
-        }
+        if (settings.printMissing)
+            printMissing(ref<Store>(store), willBuild, willSubstitute, unknown, downloadSize, narSize);
 
         if (!dryRun)
-            aio.blockOn(store->buildPaths(paths, buildMode, evalStore));
+            store->buildPaths(paths, buildMode, evalStore);
     };
 
     if (runEnv) {
@@ -328,7 +327,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
             throw UsageError("nix-shell requires a single derivation");
 
         auto & drvInfo = drvs.front();
-        auto drv = aio.blockOn(evalStore->derivationFromPath(drvInfo.requireDrvPath(*state)));
+        auto drv = evalStore->derivationFromPath(drvInfo.requireDrvPath(*state));
 
         std::vector<DerivedPath> pathsToBuild;
         RealisedPath::Set pathsToCopy;
@@ -355,7 +354,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
 
                 auto bashDrv = drv->requireDrvPath(*state);
                 pathsToBuild.push_back(DerivedPath::Built {
-                    .drvPath = makeConstantStorePath(bashDrv),
+                    .drvPath = makeConstantStorePathRef(bashDrv),
                     .outputs = OutputsSpec::Names {"out"},
                 });
                 pathsToCopy.insert(bashDrv);
@@ -368,25 +367,31 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
             }
         }
 
-        auto accumDerivedPath = [&](SingleDerivedPath::Opaque inputDrv, const StringSet & inputNode) {
-            if (!inputNode.empty())
+        std::function<void(ref<SingleDerivedPath>, const DerivedPathMap<StringSet>::ChildNode &)> accumDerivedPath;
+
+        accumDerivedPath = [&](ref<SingleDerivedPath> inputDrv, const DerivedPathMap<StringSet>::ChildNode & inputNode) {
+            if (!inputNode.value.empty())
                 pathsToBuild.push_back(DerivedPath::Built {
                     .drvPath = inputDrv,
-                    .outputs = OutputsSpec::Names { inputNode },
+                    .outputs = OutputsSpec::Names { inputNode.value },
                 });
+            for (const auto & [outputName, childNode] : inputNode.childMap)
+                accumDerivedPath(
+                    make_ref<SingleDerivedPath>(SingleDerivedPath::Built { inputDrv, outputName }),
+                    childNode);
         };
 
         // Build or fetch all dependencies of the derivation.
-        for (const auto & [inputDrv0, inputNode] : drv.inputDrvs) {
+        for (const auto & [inputDrv0, inputNode] : drv.inputDrvs.map) {
             // To get around lambda capturing restrictions in the
             // standard.
             const auto & inputDrv = inputDrv0;
             if (std::all_of(envExclude.cbegin(), envExclude.cend(),
                     [&](const std::string & exclude) {
-                        return !std::regex_search(store->printStorePath(inputDrv), regex::parse(exclude));
+                        return !std::regex_search(store->printStorePath(inputDrv), std::regex(exclude));
                     }))
             {
-                accumDerivedPath(makeConstantStorePath(inputDrv), inputNode);
+                accumDerivedPath(makeConstantStorePathRef(inputDrv), inputNode);
                 pathsToCopy.insert(inputDrv);
             }
         }
@@ -400,9 +405,14 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
         if (dryRun) return;
 
         if (shellDrv) {
-            auto shellDrvOutputs =
-                aio.blockOn(store->queryDerivationOutputMap(shellDrv.value(), &*evalStore));
-            shell = store->printStorePath(shellDrvOutputs.at("out")) + "/bin/bash";
+            auto shellDrvOutputs = store->queryPartialDerivationOutputMap(shellDrv.value(), &*evalStore);
+            shell = store->printStorePath(shellDrvOutputs.at("out").value()) + "/bin/bash";
+        }
+
+        if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations)) {
+            auto resolvedDrv = drv.tryResolve(*store);
+            assert(resolvedDrv && "Successfully resolved the derivation");
+            drv = *resolvedDrv;
         }
 
         // Set the environment.
@@ -443,21 +453,24 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
         if (env.count("__json")) {
             StorePathSet inputs;
 
-            auto accumInputClosure = [&](const StorePath & inputDrv, const StringSet & inputNode) {
-                auto outputs =
-                    aio.blockOn(store->queryDerivationOutputMap(inputDrv, &*evalStore));
-                for (auto & i : inputNode) {
+            std::function<void(const StorePath &, const DerivedPathMap<StringSet>::ChildNode &)> accumInputClosure;
+
+            accumInputClosure = [&](const StorePath & inputDrv, const DerivedPathMap<StringSet>::ChildNode & inputNode) {
+                auto outputs = store->queryPartialDerivationOutputMap(inputDrv, &*evalStore);
+                for (auto & i : inputNode.value) {
                     auto o = outputs.at(i);
-                    aio.blockOn(store->computeFSClosure(o, inputs));
+                    store->computeFSClosure(*o, inputs);
                 }
+                for (const auto & [outputName, childNode] : inputNode.childMap)
+                    accumInputClosure(*outputs.at(outputName), childNode);
             };
 
-            for (const auto & [inputDrv, inputNode] : drv.inputDrvs)
+            for (const auto & [inputDrv, inputNode] : drv.inputDrvs.map)
                 accumInputClosure(inputDrv, inputNode);
 
             ParsedDerivation parsedDrv(drvInfo.requireDrvPath(*state), drv);
 
-            if (auto structAttrs = aio.blockOn(parsedDrv.prepareStructuredAttrs(*store, inputs))) {
+            if (auto structAttrs = parsedDrv.prepareStructuredAttrs(*store, inputs)) {
                 auto json = structAttrs.value();
                 structuredAttrsRC = writeStructuredAttrsShell(json);
 
@@ -565,7 +578,7 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
                 throw Error("derivation '%s' lacks an 'outputName' attribute", store->printStorePath(drvPath));
 
             pathsToBuild.push_back(DerivedPath::Built{
-                .drvPath = makeConstantStorePath(drvPath),
+                .drvPath = makeConstantStorePathRef(drvPath),
                 .outputs = OutputsSpec::Names{outputName},
             });
             pathsToBuildOrdered.push_back({drvPath, {outputName}});
@@ -590,15 +603,16 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
             if (counter)
                 drvPrefix += fmt("-%d", counter + 1);
 
-            auto builtOutputs =
-                aio.blockOn(store->queryDerivationOutputMap(drvPath, &*evalStore));
+            auto builtOutputs = store->queryPartialDerivationOutputMap(drvPath, &*evalStore);
 
-            auto outputPath = builtOutputs.at(outputName);
+            auto maybeOutputPath = builtOutputs.at(outputName);
+            assert(maybeOutputPath);
+            auto outputPath = *maybeOutputPath;
 
-            if (auto store2 = store.try_cast_shared<LocalFSStore>()) {
+            if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>()) {
                 std::string symlink = drvPrefix;
                 if (outputName != "out") symlink += "-" + outputName;
-                aio.blockOn(store2->addPermRoot(outputPath, absPath(symlink)));
+                store2->addPermRoot(outputPath, absPath(symlink));
             }
 
             outPaths.push_back(outputPath);
@@ -611,9 +625,9 @@ static void main_nix_build(AsyncIoRoot & aio, std::string programName, Strings a
     }
 }
 
-void registerLegacyNixBuildAndNixShell() {
-    LegacyCommandRegistry::add("nix-build", main_nix_build);
-    LegacyCommandRegistry::add("nix-shell", main_nix_build);
+void registerNixBuildAndNixShell() {
+    LegacyCommands::add("nix-build", main_nix_build);
+    LegacyCommands::add("nix-shell", main_nix_build);
 }
 
 }

lix/legacy/nix-build.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixBuildAndNixShell();
+void registerNixBuildAndNixShell();
 
 }

lix/legacy/nix-channel.cc

@@ -7,8 +7,6 @@
 #include "lix/libfetchers/fetchers.hh"
 #include "lix/libexpr/eval-settings.hh" // for defexpr
 #include "lix/libstore/temporary-dir.hh"
-#include "lix/libutil/async.hh"
-#include "lix/libutil/regex.hh"
 #include "lix/libutil/users.hh"
 #include "nix-channel.hh"
 
@@ -31,10 +29,10 @@ static void readChannels()
 
     for (const auto & line : tokenizeString<std::vector<std::string>>(channelsFile, "\n")) {
         chomp(line);
-        if (std::regex_search(line, regex::parse("^\\s*\\#")))
+        if (std::regex_search(line, std::regex("^\\s*\\#")))
             continue;
         auto split = tokenizeString<std::vector<std::string>>(line, " ");
-        auto url = std::regex_replace(split[0], regex::parse("/*$"), "");
+        auto url = std::regex_replace(split[0], std::regex("/*$"), "");
         auto name = split.size() > 1 ? split[1] : std::string(baseNameOf(url));
         channels[name] = url;
     }
@@ -53,9 +51,9 @@ static void writeChannels()
 // Adds a channel.
 static void addChannel(const std::string & url, const std::string & name)
 {
-    if (!regex_search(url, regex::parse("^(file|http|https)://")))
+    if (!regex_search(url, std::regex("^(file|http|https)://")))
         throw Error("invalid channel URL '%1%'", url);
-    if (!regex_search(name, regex::parse("^[a-zA-Z0-9_][a-zA-Z0-9_\\.-]*$")))
+    if (!regex_search(name, std::regex("^[a-zA-Z0-9_][a-zA-Z0-9_\\.-]*$")))
         throw Error("invalid channel identifier '%1%'", name);
     readChannels();
     channels[name] = url;
@@ -77,11 +75,11 @@ static void removeChannel(const std::string & name)
 static Path nixDefExpr;
 
 // Fetch Nix expressions and binary cache URLs from the subscribed channels.
-static void update(AsyncIoRoot & aio, const StringSet & channelNames)
+static void update(const StringSet & channelNames)
 {
     readChannels();
 
-    auto store = aio.blockOn(openStore());
+    auto store = openStore();
 
     auto [fd, unpackChannelPath] = createTempFile();
     writeFull(fd.get(),
@@ -102,7 +100,7 @@ static void update(AsyncIoRoot & aio, const StringSet & channelNames)
         auto cname = name;
         std::smatch match;
         auto urlBase = std::string(baseNameOf(url));
-        if (std::regex_search(urlBase, match, regex::parse("(-\\d.*)$")))
+        if (std::regex_search(urlBase, match, std::regex("(-\\d.*)$")))
             cname = cname + match.str(1);
 
         std::string extraAttrs;
@@ -116,17 +114,12 @@ static void update(AsyncIoRoot & aio, const StringSet & channelNames)
             // We want to download the url to a file to see if it's a tarball while also checking if we
             // got redirected in the process, so that we can grab the various parts of a nix channel
             // definition from a consistent location if the redirect changes mid-download.
-            auto result = aio.blockOn(fetchers::downloadFile(
-                store,
-                url,
-                std::string(baseNameOf(url)),
-                false
-            ));
+            auto result = fetchers::downloadFile(store, url, std::string(baseNameOf(url)), false);
             auto filename = store->toRealPath(result.storePath);
             url = result.effectiveUrl;
 
             bool unpacked = false;
-            if (std::regex_search(filename, regex::parse("\\.tar\\.(gz|bz2|xz)$"))) {
+            if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) {
                 runProgram(settings.nixBinDir + "/nix-build", false, { "--no-out-link", "--expr", "import " + unpackChannelPath +
                             "{ name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; }" });
                 unpacked = true;
@@ -134,17 +127,11 @@ static void update(AsyncIoRoot & aio, const StringSet & channelNames)
 
             if (!unpacked) {
                 // Download the channel tarball.
-                std::optional<fetchers::DownloadFileResult> exprs;
                 try {
-                    exprs = aio.blockOn(fetchers::downloadFile(
-                        store, url + "/nixexprs.tar.xz", "nixexprs.tar.xz", false
-                    ));
+                    filename = store->toRealPath(fetchers::downloadFile(store, url + "/nixexprs.tar.xz", "nixexprs.tar.xz", false).storePath);
                 } catch (FileTransferError & e) {
-                    exprs = aio.blockOn(fetchers::downloadFile(
-                        store, url + "/nixexprs.tar.bz2", "nixexprs.tar.bz2", false
-                    ));
+                    filename = store->toRealPath(fetchers::downloadFile(store, url + "/nixexprs.tar.bz2", "nixexprs.tar.bz2", false).storePath);
                 }
-                filename = store->toRealPath(exprs->storePath);
             }
             // Regardless of where it came from, add the expression representing this channel to accumulated expression
             exprs.push_back("f: f { name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; " + extraAttrs + " }");
@@ -175,7 +162,7 @@ static void update(AsyncIoRoot & aio, const StringSet & channelNames)
     replaceSymlink(profile, channelLink);
 }
 
-static int main_nix_channel(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_nix_channel(std::string programName, Strings argv)
 {
     {
         // Figure out the name of the `.nix-channels' file to use
@@ -197,7 +184,7 @@ static int main_nix_channel(AsyncIoRoot & aio, std::string programName, Strings
             cRollback
         } cmd = cNone;
         std::vector<std::string> args;
-        LegacyArgs(aio, programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+        LegacyArgs(programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
             if (*arg == "--help") {
                 showManPage("nix-channel");
             } else if (*arg == "--version") {
@@ -235,8 +222,8 @@ static int main_nix_channel(AsyncIoRoot & aio, std::string programName, Strings
                     name = args[1];
                 } else {
                     name = baseNameOf(url);
-                    name = std::regex_replace(name, regex::parse("-unstable$"), "");
-                    name = std::regex_replace(name, regex::parse("-stable$"), "");
+                    name = std::regex_replace(name, std::regex("-unstable$"), "");
+                    name = std::regex_replace(name, std::regex("-stable$"), "");
                 }
                 addChannel(url, name);
                 }
@@ -254,7 +241,7 @@ static int main_nix_channel(AsyncIoRoot & aio, std::string programName, Strings
                     std::cout << channel.first << ' ' << channel.second << '\n';
                 break;
             case cUpdate:
-                update(aio, StringSet(args.begin(), args.end()));
+                update(StringSet(args.begin(), args.end()));
                 break;
             case cListGenerations:
                 if (!args.empty())
@@ -279,8 +266,8 @@ static int main_nix_channel(AsyncIoRoot & aio, std::string programName, Strings
     }
 }
 
-void registerLegacyNixChannel() {
-    LegacyCommandRegistry::add("nix-channel", main_nix_channel);
+void registerNixChannel() {
+    LegacyCommands::add("nix-channel", main_nix_channel);
 }
 
 }

lix/legacy/nix-channel.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixChannel();
+void registerNixChannel();
 
 }

lix/legacy/nix-collect-garbage.cc

@@ -7,9 +7,9 @@
 #include "lix/libstore/globals.hh"
 #include "lix/libcmd/legacy.hh"
 #include "lix/libutil/signals.hh"
-#include "lix/libutil/types.hh"
 #include "nix-collect-garbage.hh"
 
+#include <iostream>
 #include <cerrno>
 
 namespace nix {
@@ -22,7 +22,7 @@ bool dryRun = false;
  * Of course, this makes rollbacks to before this point in time
  * impossible. */
 
-static void removeOldGenerations(std::string dir, NeverAsync = {})
+void removeOldGenerations(std::string dir)
 {
     if (access(dir.c_str(), R_OK) != 0) return;
 
@@ -56,14 +56,14 @@ static void removeOldGenerations(std::string dir, NeverAsync = {})
     }
 }
 
-static int main_nix_collect_garbage(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_nix_collect_garbage(std::string programName, Strings argv)
 {
     {
         bool removeOld = false;
 
         GCOptions options;
 
-        LegacyArgs(aio, programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+        LegacyArgs(programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
             if (*arg == "--help")
                 showManPage("nix-collect-garbage");
             else if (*arg == "--version")
@@ -94,11 +94,11 @@ static int main_nix_collect_garbage(AsyncIoRoot & aio, std::string programName,
         } else {
             options.action = GCOptions::gcReturnDead;
         }
-        auto store = aio.blockOn(openStore());
+        auto store = openStore();
         auto & gcStore = require<GcStore>(*store);
         GCResults results;
         PrintFreed freed(true, results);
-        aio.blockOn(gcStore.collectGarbage(options, results));
+        gcStore.collectGarbage(options, results);
 
         if (dryRun) {
             // Only print results for dry run; when !dryRun, paths will be printed as they're deleted.
@@ -111,8 +111,8 @@ static int main_nix_collect_garbage(AsyncIoRoot & aio, std::string programName,
     }
 }
 
-void registerLegacyNixCollectGarbage() {
-    LegacyCommandRegistry::add("nix-collect-garbage", main_nix_collect_garbage);
+void registerNixCollectGarbage() {
+    LegacyCommands::add("nix-collect-garbage", main_nix_collect_garbage);
 }
 
 }

lix/legacy/nix-collect-garbage.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixCollectGarbage();
+void registerNixCollectGarbage();
 
 }

lix/legacy/nix-copy-closure.cc

@@ -5,7 +5,7 @@
 
 namespace nix {
 
-static int main_nix_copy_closure(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_nix_copy_closure(std::string programName, Strings argv)
 {
     {
         auto gzip = false;
@@ -16,7 +16,7 @@ static int main_nix_copy_closure(AsyncIoRoot & aio, std::string programName, Str
         std::string sshHost;
         PathSet storePaths;
 
-        LegacyArgs(aio, programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+        LegacyArgs(programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
             if (*arg == "--help")
                 showManPage("nix-copy-closure");
             else if (*arg == "--version")
@@ -48,21 +48,21 @@ static int main_nix_copy_closure(AsyncIoRoot & aio, std::string programName, Str
             throw UsageError("no host name specified");
 
         auto remoteUri = "ssh://" + sshHost + (gzip ? "?compress=true" : "");
-        auto to = aio.blockOn(toMode ? openStore(remoteUri) : openStore());
-        auto from = aio.blockOn(toMode ? openStore() : openStore(remoteUri));
+        auto to = toMode ? openStore(remoteUri) : openStore();
+        auto from = toMode ? openStore() : openStore(remoteUri);
 
         RealisedPath::Set storePaths2;
         for (auto & path : storePaths)
             storePaths2.insert(from->followLinksToStorePath(path));
 
-        aio.blockOn(copyClosure(*from, *to, storePaths2, NoRepair, NoCheckSigs, useSubstitutes));
+        copyClosure(*from, *to, storePaths2, NoRepair, NoCheckSigs, useSubstitutes);
 
         return 0;
     }
 }
 
-void registerLegacyNixCopyClosure() {
-    LegacyCommandRegistry::add("nix-copy-closure", main_nix_copy_closure);
+void registerNixCopyClosure() {
+    LegacyCommands::add("nix-copy-closure", main_nix_copy_closure);
 }
 
 }

lix/legacy/nix-copy-closure.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixCopyClosure();
+void registerNixCopyClosure();
 
 }

lix/legacy/nix-env.cc

@@ -28,6 +28,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <nlohmann/json.hpp>
 
 using std::cout;
 
@@ -56,7 +57,6 @@ struct InstallSourceInfo
 
 struct Globals
 {
-    AsyncIoRoot & aio;
     InstallSourceInfo instSource;
     Path profile;
     std::shared_ptr<Evaluator> state;
@@ -229,8 +229,8 @@ static std::strong_ordering comparePriorities(EvalState & state, DrvInfo & drv1,
 static bool isPrebuilt(EvalState & state, DrvInfo & elem)
 {
     auto path = elem.queryOutPath(state);
-    if (state.aio.blockOn(state.ctx.store->isValidPath(path))) return true;
-    return state.aio.blockOn(state.ctx.store->querySubstitutablePaths({path})).count(path);
+    if (state.ctx.store->isValidPath(path)) return true;
+    return state.ctx.store->querySubstitutablePaths({path}).count(path);
 }
 
 
@@ -447,8 +447,7 @@ static void queryInstSources(EvalState & state,
 
                 if (path.isDerivation()) {
                     elem.setDrvPath(path);
-                    auto outputs =
-                        state.aio.blockOn(state.ctx.store->queryDerivationOutputMap(path));
+                    auto outputs = state.ctx.store->queryDerivationOutputMap(path);
                     elem.setOutPath(outputs.at("out"));
                     if (name.size() >= drvExtension.size() &&
                         std::string(name, name.size() - drvExtension.size()) == drvExtension)
@@ -495,7 +494,7 @@ static void printMissing(EvalState & state, DrvInfos & elems)
     for (auto & i : elems)
         if (auto drvPath = i.queryDrvPath(state))
             targets.emplace_back(DerivedPath::Built{
-                .drvPath = makeConstantStorePath(*drvPath),
+                .drvPath = makeConstantStorePathRef(*drvPath),
                 .outputs = OutputsSpec::All { },
             });
         else
@@ -503,7 +502,7 @@ static void printMissing(EvalState & state, DrvInfos & elems)
                 .path = i.queryOutPath(state),
             });
 
-    state.aio.blockOn(printMissing(state.ctx.store, targets));
+    printMissing(state.ctx.store, targets);
 }
 
 
@@ -512,20 +511,13 @@ static bool keep(EvalState & state, DrvInfo & drv)
     return drv.queryMetaBool(state, "keep", false);
 }
 
-static void setMetaFlag(EvalState & state, DrvInfo & drv,
-    const std::string & name, const std::string & value)
-{
-    auto v = state.ctx.mem.allocValue();
-    v->mkString(value);
-    drv.setMeta(state, name, v);
-}
 
 static void installDerivations(Globals & globals,
-    const Strings & args, const Path & profile, std::optional<int> priority)
+    const Strings & args, const Path & profile)
 {
     debug("installing derivations");
 
-    auto state = globals.state->begin(globals.aio);
+    auto state = globals.state->begin();
 
     /* Get the set of user environment elements to be installed. */
     DrvInfos newElems, newElemsTmp;
@@ -547,11 +539,6 @@ static void installDerivations(Globals & globals,
         newNames.insert(DrvName(i.queryName(*state)).name);
     }
 
-    if (priority) {
-        for (auto & drv : newElems) {
-            setMetaFlag(*state, drv, "priority", std::to_string((priority.value())));
-        }
-    }
 
     while (true) {
         auto lockToken = optimisticLockProfile(profile);
@@ -589,7 +576,6 @@ static void installDerivations(Globals & globals,
 
 static void opInstall(Globals & globals, Strings opFlags, Strings opArgs)
 {
-    std::optional<int> priority;
     for (Strings::iterator i = opFlags.begin(); i != opFlags.end(); ) {
         auto arg = *i++;
         if (parseInstallSourceOptions(globals, i, opFlags, arg)) ;
@@ -597,17 +583,10 @@ static void opInstall(Globals & globals, Strings opFlags, Strings opArgs)
             globals.preserveInstalled = true;
         else if (arg == "--remove-all" || arg == "-r")
             globals.removeAll = true;
-        else if (arg == "--priority") {
-            if (i == opFlags.end())
-                throw UsageError("'%1%' requires an argument", arg);
-            priority = string2Int<int>(*i++);
-            if (!priority)
-                throw UsageError("'--priority' requires an integer argument");
-        }
         else throw UsageError("unknown flag '%1%'", arg);
     }
 
-    installDerivations(globals, opArgs, globals.profile, priority);
+    installDerivations(globals, opArgs, globals.profile);
 }
 
 
@@ -619,7 +598,7 @@ static void upgradeDerivations(Globals & globals,
 {
     debug("upgrading derivations");
 
-    auto state = globals.state->begin(globals.aio);
+    auto state = globals.state->begin();
 
     /* Upgrade works as follows: we take all currently installed
        derivations, and for any derivation matching any selector, look
@@ -724,6 +703,15 @@ static void opUpgrade(Globals & globals, Strings opFlags, Strings opArgs)
 }
 
 
+static void setMetaFlag(EvalState & state, DrvInfo & drv,
+    const std::string & name, const std::string & value)
+{
+    auto v = state.ctx.mem.allocValue();
+    v->mkString(value);
+    drv.setMeta(state, name, v);
+}
+
+
 static void opSetFlag(Globals & globals, Strings opFlags, Strings opArgs)
 {
     if (opFlags.size() > 0)
@@ -736,7 +724,7 @@ static void opSetFlag(Globals & globals, Strings opFlags, Strings opArgs)
     std::string flagValue = *arg++;
     DrvNames selectors = drvNamesFromArgs(Strings(arg, opArgs.end()));
 
-    auto state = globals.state->begin(globals.aio);
+    auto state = globals.state->begin();
 
     while (true) {
         std::string lockToken = optimisticLockProfile(globals.profile);
@@ -766,9 +754,9 @@ static void opSetFlag(Globals & globals, Strings opFlags, Strings opArgs)
 
 static void opSet(Globals & globals, Strings opFlags, Strings opArgs)
 {
-    auto state = globals.state->begin(globals.aio);
+    auto state = globals.state->begin();
 
-    auto store2 = globals.state->store.try_cast_shared<LocalFSStore>();
+    auto store2 = globals.state->store.dynamic_pointer_cast<LocalFSStore>();
     if (!store2) throw Error("--set is not supported for this Nix store");
 
     for (Strings::iterator i = opFlags.begin(); i != opFlags.end(); ) {
@@ -792,24 +780,22 @@ static void opSet(Globals & globals, Strings opFlags, Strings opArgs)
     std::vector<DerivedPath> paths {
         drvPath
         ? (DerivedPath) (DerivedPath::Built {
-            .drvPath = makeConstantStorePath(*drvPath),
+            .drvPath = makeConstantStorePathRef(*drvPath),
             .outputs = OutputsSpec::All { },
         })
         : (DerivedPath) (DerivedPath::Opaque {
             .path = drv.queryOutPath(*state),
         }),
     };
-    globals.aio.blockOn(printMissing(globals.state->store, paths));
+    printMissing(globals.state->store, paths);
     if (globals.dryRun) return;
-    globals.aio.blockOn(
-        globals.state->store->buildPaths(paths, globals.state->repair ? bmRepair : bmNormal)
-    );
+    globals.state->store->buildPaths(paths, globals.state->repair ? bmRepair : bmNormal);
 
     debug("switching to new user environment");
-    Path generation = globals.aio.blockOn(createGeneration(
+    Path generation = createGeneration(
         *store2,
         globals.profile,
-        drv.queryOutPath(*state)));
+        drv.queryOutPath(*state));
     switchLink(globals.profile, generation);
 }
 
@@ -817,7 +803,7 @@ static void opSet(Globals & globals, Strings opFlags, Strings opArgs)
 static void uninstallDerivations(Globals & globals, Strings & selectors,
     Path & profile)
 {
-    auto state = globals.state->begin(globals.aio);
+    auto state = globals.state->begin();
 
     while (true) {
         auto lockToken = optimisticLockProfile(profile);
@@ -960,14 +946,15 @@ static VersionDiff compareVersionAgainstSet(
 
 static void queryJSON(EvalState & state, Globals & globals, std::vector<DrvInfo> & elems, bool printOutPath, bool printDrvPath, bool printMeta)
 {
-    JSON topObj = JSON::object();
+    using nlohmann::json;
+    json topObj = json::object();
     for (auto & i : elems) {
         try {
             if (i.hasFailed()) continue;
 
 
             auto drvName = DrvName(i.queryName(state));
-            JSON &pkgObj = topObj[i.attrPath];
+            json &pkgObj = topObj[i.attrPath];
             pkgObj = {
                 {"name", drvName.fullName},
                 {"pname", drvName.name},
@@ -978,8 +965,8 @@ static void queryJSON(EvalState & state, Globals & globals, std::vector<DrvInfo>
 
             {
                 DrvInfo::Outputs outputs = i.queryOutputs(state, printOutPath);
-                JSON &outputObj = pkgObj["outputs"];
-                outputObj = JSON::object();
+                json &outputObj = pkgObj["outputs"];
+                outputObj = json::object();
                 for (auto & j : outputs) {
                     if (j.second)
                         outputObj[j.first] = globals.state->store->printStorePath(*j.second);
@@ -994,8 +981,8 @@ static void queryJSON(EvalState & state, Globals & globals, std::vector<DrvInfo>
             }
 
             if (printMeta) {
-                JSON &metaObj = pkgObj["meta"];
-                metaObj = JSON::object();
+                json &metaObj = pkgObj["meta"];
+                metaObj = json::object();
                 StringSet metaNames = i.queryMetaNames(state);
                 for (auto & j : metaNames) {
                     Value * v = i.queryMeta(state, j);
@@ -1022,7 +1009,7 @@ static void queryJSON(EvalState & state, Globals & globals, std::vector<DrvInfo>
 static void opQuery(Globals & globals, Strings opFlags, Strings opArgs)
 {
     auto & store { *globals.state->store };
-    auto state = globals.state->begin(globals.aio);
+    auto state = globals.state->begin();
 
     Strings remaining;
     std::string attrPath;
@@ -1112,8 +1099,8 @@ static void opQuery(Globals & globals, Strings opFlags, Strings opArgs)
                 printMsg(lvlTalkative, "skipping derivation named '%s' which gives an assertion failure", i.queryName(*state));
                 i.setFailed();
             }
-        validPaths = globals.aio.blockOn(store.queryValidPaths(paths));
-        substitutablePaths = globals.aio.blockOn(store.querySubstitutablePaths(paths));
+        validPaths = store.queryValidPaths(paths);
+        substitutablePaths = store.querySubstitutablePaths(paths);
     }
 
 
@@ -1369,7 +1356,8 @@ static void opListGenerations(Globals & globals, Strings opFlags, Strings opArgs
     if (opArgs.size() != 0)
         throw UsageError("no arguments expected");
 
-    PathLock lock = lockProfile(globals.profile);
+    PathLocks lock;
+    lockProfile(lock, globals.profile);
 
     auto [gens, curGen] = findGenerations(globals.profile);
 
@@ -1424,7 +1412,7 @@ static void opVersion(Globals & globals, Strings opFlags, Strings opArgs)
 }
 
 
-static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_nix_env(std::string programName, Strings argv)
 {
     {
         Strings opFlags, opArgs;
@@ -1433,7 +1421,7 @@ static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv
         bool showHelp = false;
         std::string file;
 
-        Globals globals{aio, {}, {}, {}, {}, {}, {}, {}, {}};
+        Globals globals;
 
         globals.instSource.type = srcUnknown;
         globals.instSource.systemFilter = "*";
@@ -1463,7 +1451,7 @@ static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv
             using LegacyArgs::LegacyArgs;
         };
 
-        MyArgs myArgs(aio, programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+        MyArgs myArgs(programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
             Operation oldOp = op;
 
             if (*arg == "--help")
@@ -1532,8 +1520,7 @@ static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv
                 opFlags.push_back(*arg);
                 /* FIXME: hacky */
                 if (*arg == "--from-profile" ||
-                    (op == opQuery && (*arg == "--attr" || *arg == "-A")) ||
-                    (op == opInstall && (*arg == "--priority")))
+                    (op == opQuery && (*arg == "--attr" || *arg == "-A")))
                     opFlags.push_back(getArg(*arg, arg, end));
             }
             else
@@ -1550,14 +1537,14 @@ static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv
         if (showHelp) showManPage("nix-env" + opName);
         if (!op) throw UsageError("no operation specified");
 
-        auto store = aio.blockOn(openStore());
+        auto store = openStore();
 
-        globals.state = std::make_shared<Evaluator>(aio, myArgs.searchPath, store);
+        globals.state = std::make_shared<Evaluator>(myArgs.searchPath, store);
         globals.state->repair = myArgs.repair;
 
         globals.instSource.nixExprPath = std::make_shared<SourcePath>(
             file != ""
-            ? aio.blockOn(lookupFileArg(*globals.state, file)).unwrap()
+            ? lookupFileArg(*globals.state, file)
             : CanonPath(nixExprPath));
 
         globals.instSource.autoArgs = myArgs.getAutoArgs(*globals.state);
@@ -1576,8 +1563,8 @@ static int main_nix_env(AsyncIoRoot & aio, std::string programName, Strings argv
     }
 }
 
-void registerLegacyNixEnv() {
-    LegacyCommandRegistry::add("nix-env", main_nix_env);
+void registerNixEnv() {
+    LegacyCommands::add("nix-env", main_nix_env);
 }
 
 }

lix/legacy/nix-env.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixEnv();
+void registerNixEnv();
 
 }

lix/legacy/nix-instantiate.cc

@@ -2,6 +2,7 @@
 #include "lix/libexpr/print-ambiguous.hh"
 #include "lix/libmain/shared.hh"
 #include "lix/libexpr/eval.hh"
+#include "lix/libexpr/eval-inline.hh"
 #include "lix/libexpr/get-drvs.hh"
 #include "lix/libexpr/attr-path.hh"
 #include "lix/libexpr/value-to-xml.hh"
@@ -12,6 +13,7 @@
 #include "lix/libcmd/legacy.hh"
 #include "nix-instantiate.hh"
 
+#include <map>
 #include <iostream>
 
 
@@ -29,7 +31,7 @@ void processExpr(EvalState & state, const Strings & attrPaths,
     bool evalOnly, OutputKind output, bool location, Expr & e)
 {
     if (parseOnly) {
-        std::cout << e.toJSON(state.ctx.symbols).dump(2);
+        e.show(state.ctx.symbols, std::cout);
         std::cout << "\n";
         return;
     }
@@ -39,7 +41,7 @@ void processExpr(EvalState & state, const Strings & attrPaths,
 
     for (auto & i : attrPaths) {
         Value & v(*findAlongAttrPath(state, i, autoArgs, vRoot).first);
-        state.forceValue(v, noPos);
+        state.forceValue(v, v.determinePos(noPos));
 
         NixStringContext context;
         if (evalOnly) {
@@ -47,11 +49,11 @@ void processExpr(EvalState & state, const Strings & attrPaths,
             if (autoArgs.empty())
                 vRes = v;
             else
-                state.autoCallFunction(autoArgs, v, vRes, noPos);
+                state.autoCallFunction(autoArgs, v, vRes);
             if (output == okXML)
                 printValueAsXML(state, strict, location, vRes, std::cout, context, noPos);
             else if (output == okJSON) {
-                printValueAsJSON(state, strict, vRes, noPos, std::cout, context);
+                printValueAsJSON(state, strict, vRes, v.determinePos(noPos), std::cout, context);
                 std::cout << std::endl;
             } else {
                 if (strict) state.forceValueDeep(vRes);
@@ -76,9 +78,9 @@ void processExpr(EvalState & state, const Strings & attrPaths,
                 else {
                     Path rootName = absPath(gcRoot);
                     if (++rootNr > 1) rootName += "-" + std::to_string(rootNr);
-                    auto store2 = state.ctx.store.try_cast_shared<LocalFSStore>();
+                    auto store2 = state.ctx.store.dynamic_pointer_cast<LocalFSStore>();
                     if (store2)
-                        drvPathS = state.aio.blockOn(store2->addPermRoot(drvPath, rootName));
+                        drvPathS = store2->addPermRoot(drvPath, rootName);
                 }
                 std::cout << fmt("%s%s\n", drvPathS, (outputName != "out" ? "!" + outputName : ""));
             }
@@ -87,7 +89,7 @@ void processExpr(EvalState & state, const Strings & attrPaths,
 }
 
 
-static int main_nix_instantiate(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_nix_instantiate(std::string programName, Strings argv)
 {
     {
         Strings files;
@@ -107,7 +109,7 @@ static int main_nix_instantiate(AsyncIoRoot & aio, std::string programName, Stri
             using LegacyArgs::LegacyArgs;
         };
 
-        MyArgs myArgs(aio, programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+        MyArgs myArgs(programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
             if (*arg == "--help")
                 showManPage("nix-instantiate");
             else if (*arg == "--version")
@@ -152,11 +154,11 @@ static int main_nix_instantiate(AsyncIoRoot & aio, std::string programName, Stri
         if (evalOnly && !wantsReadWrite)
             settings.readOnlyMode = true;
 
-        auto store = aio.blockOn(openStore());
-        auto evalStore = myArgs.evalStoreUrl ? aio.blockOn(openStore(*myArgs.evalStoreUrl)) : store;
+        auto store = openStore();
+        auto evalStore = myArgs.evalStoreUrl ? openStore(*myArgs.evalStoreUrl) : store;
 
-        auto evaluator = std::make_unique<Evaluator>(aio, myArgs.searchPath, evalStore, store);
-        auto state = evaluator->begin(aio);
+        auto evaluator = std::make_unique<Evaluator>(myArgs.searchPath, evalStore, store);
+        auto state = evaluator->begin();
         evaluator->repair = myArgs.repair;
 
         Bindings & autoArgs = *myArgs.getAutoArgs(*evaluator);
@@ -165,7 +167,7 @@ static int main_nix_instantiate(AsyncIoRoot & aio, std::string programName, Stri
 
         if (findFile) {
             for (auto & i : files) {
-                auto p = aio.blockOn(evaluator->paths.findFile(i)).unwrap();
+                auto p = evaluator->paths.findFile(i);
                 std::cout << p.canonical().abs() << std::endl;
             }
             return 0;
@@ -179,10 +181,9 @@ static int main_nix_instantiate(AsyncIoRoot & aio, std::string programName, Stri
             files.push_back("./default.nix");
 
         for (auto & i : files) {
-            Expr & e = fromArgs ? evaluator->parseExprFromString(i, CanonPath::fromCwd())
-                                : evaluator->parseExprFromFile(evaluator->paths.resolveExprPath(
-                                      aio.blockOn(lookupFileArg(*evaluator, i)).unwrap()
-                                  ));
+            Expr & e = fromArgs
+                ? evaluator->parseExprFromString(i, CanonPath::fromCwd())
+                : evaluator->parseExprFromFile(evaluator->paths.resolveExprPath(lookupFileArg(*evaluator, i)));
             processExpr(*state, attrPaths, parseOnly, strict, autoArgs,
                 evalOnly, outputKind, xmlOutputSourceLocation, e);
         }
@@ -193,8 +194,8 @@ static int main_nix_instantiate(AsyncIoRoot & aio, std::string programName, Stri
     }
 }
 
-void registerLegacyNixInstantiate() {
-    LegacyCommandRegistry::add("nix-instantiate", main_nix_instantiate);
+void registerNixInstantiate() {
+    LegacyCommands::add("nix-instantiate", main_nix_instantiate);
 }
 
 }

lix/legacy/nix-instantiate.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixInstantiate();
+void registerNixInstantiate();
 
 }

lix/legacy/nix-store.cc

@@ -1,18 +1,16 @@
 #include "lix/libutil/archive.hh"
 #include "lix/libstore/derivations.hh"
 #include "dotgraph.hh"
-#include "lix/libutil/async-io.hh"
-#include "lix/libutil/async.hh"
 #include "lix/libutil/exit.hh"
 #include "lix/libstore/globals.hh"
-#include "lix/libstore/build-result.hh" // IWYU pragma: keep
+#include "lix/libstore/build-result.hh"
 #include "lix/libstore/store-cast.hh"
 #include "lix/libstore/gc-store.hh"
 #include "lix/libstore/log-store.hh"
 #include "lix/libstore/local-store.hh"
 #include "lix/libutil/monitor-fd.hh"
 #include "lix/libstore/serve-protocol.hh"
-#include "lix/libstore/serve-protocol-impl.hh" // IWYU pragma: keep
+#include "lix/libstore/serve-protocol-impl.hh"
 #include "lix/libmain/shared.hh"
 #include "graphml.hh"
 #include "lix/libcmd/legacy.hh"
@@ -34,7 +32,7 @@ using std::cin;
 using std::cout;
 
 
-typedef void (* Operation) (AsyncIoRoot & aio, Strings opFlags, Strings opArgs);
+typedef void (* Operation) (Strings opFlags, Strings opArgs);
 
 
 static Path gcRoot;
@@ -47,32 +45,30 @@ ref<LocalStore> ensureLocalStore()
 {
     auto store2 = std::dynamic_pointer_cast<LocalStore>(store);
     if (!store2) throw Error("you don't have sufficient rights to use this command");
-    return ref<LocalStore>::unsafeFromPtr(store2);
+    return ref<LocalStore>(store2);
 }
 
 
-static kj::Promise<Result<StorePath>> useDeriver(const StorePath & path)
-try {
-    if (path.isDerivation()) co_return path;
-    auto info = TRY_AWAIT(store->queryPathInfo(path));
+static StorePath useDeriver(const StorePath & path)
+{
+    if (path.isDerivation()) return path;
+    auto info = store->queryPathInfo(path);
     if (!info->deriver)
         throw Error("deriver of path '%s' is not known", store->printStorePath(path));
-    co_return *info->deriver;
-} catch (...) {
-    co_return result::current_exception();
+    return *info->deriver;
 }
 
 
 /* Realise the given path.  For a derivation that means build it; for
    other paths it means ensure their validity. */
-static kj::Promise<Result<PathSet>> realisePath(StorePathWithOutputs path, bool build = true)
-try {
+static PathSet realisePath(StorePathWithOutputs path, bool build = true)
+{
     auto store2 = std::dynamic_pointer_cast<LocalFSStore>(store);
 
     if (path.path.isDerivation()) {
-        if (build) TRY_AWAIT(store->buildPaths({path.toDerivedPath()}));
-        auto outputPaths = TRY_AWAIT(store->queryDerivationOutputMap(path.path));
-        Derivation drv = TRY_AWAIT(store->derivationFromPath(path.path));
+        if (build) store->buildPaths({path.toDerivedPath()});
+        auto outputPaths = store->queryDerivationOutputMap(path.path);
+        Derivation drv = store->derivationFromPath(path.path);
         rootNr++;
 
         /* FIXME: Encode this empty special case explicitly in the type. */
@@ -95,17 +91,17 @@ try {
                     Path rootName = gcRoot;
                     if (rootNr > 1) rootName += "-" + std::to_string(rootNr);
                     if (i->first != "out") rootName += "-" + i->first;
-                    retPath = TRY_AWAIT(store2->addPermRoot(outPath, rootName));
+                    retPath = store2->addPermRoot(outPath, rootName);
                 }
             }
             outputs.insert(retPath);
         }
-        co_return outputs;
+        return outputs;
     }
 
     else {
-        if (build) TRY_AWAIT(store->ensurePath(path.path));
-        else if (!TRY_AWAIT(store->isValidPath(path.path)))
+        if (build) store->ensurePath(path.path);
+        else if (!store->isValidPath(path.path))
             throw Error("path '%s' does not exist and cannot be created", store->printStorePath(path.path));
         if (store2) {
             if (gcRoot == "")
@@ -114,18 +110,16 @@ try {
                 Path rootName = gcRoot;
                 rootNr++;
                 if (rootNr > 1) rootName += "-" + std::to_string(rootNr);
-                co_return PathSet{TRY_AWAIT(store2->addPermRoot(path.path, rootName))};
+                return {store2->addPermRoot(path.path, rootName)};
             }
         }
-        co_return PathSet{store->printStorePath(path.path)};
+        return {store->printStorePath(path.path)};
     }
-} catch (...) {
-    co_return result::current_exception();
 }
 
 
 /* Realise the given paths. */
-static void opRealise(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opRealise(Strings opFlags, Strings opArgs)
 {
     bool dryRun = false;
     BuildMode buildMode = bmNormal;
@@ -144,9 +138,9 @@ static void opRealise(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
     uint64_t downloadSize, narSize;
     StorePathSet willBuild, willSubstitute, unknown;
-    aio.blockOn(store->queryMissing(
+    store->queryMissing(
         toDerivedPaths(paths),
-        willBuild, willSubstitute, unknown, downloadSize, narSize));
+        willBuild, willSubstitute, unknown, downloadSize, narSize);
 
     /* Filter out unknown paths from `paths`. */
     if (ignoreUnknown) {
@@ -157,20 +151,17 @@ static void opRealise(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         unknown = StorePathSet();
     }
 
-    if (settings.printMissing) {
-        aio.blockOn(printMissing(
-            ref<Store>::unsafeFromPtr(store), willBuild, willSubstitute, unknown, downloadSize, narSize
-        ));
-    }
+    if (settings.printMissing)
+        printMissing(ref<Store>(store), willBuild, willSubstitute, unknown, downloadSize, narSize);
 
     if (dryRun) return;
 
     /* Build all paths at the same time to exploit parallelism. */
-    aio.blockOn(store->buildPaths(toDerivedPaths(paths), buildMode));
+    store->buildPaths(toDerivedPaths(paths), buildMode);
 
     if (!ignoreUnknown)
         for (auto & i : paths) {
-            auto paths2 = aio.blockOn(realisePath(i, false));
+            auto paths2 = realisePath(i, false);
             if (!noOutput)
                 for (auto & j : paths2)
                     cout << fmt("%1%\n", j);
@@ -179,24 +170,18 @@ static void opRealise(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
 
 /* Add files to the Nix store and print the resulting paths. */
-static void opAdd(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opAdd(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
 
-    for (auto & i : opArgs) {
-        cout << fmt(
-            "%s\n",
-            store->printStorePath(aio.blockOn(
-                store->addToStoreRecursive(std::string(baseNameOf(i)), *prepareDump(i))
-            ))
-        );
-    }
+    for (auto & i : opArgs)
+        cout << fmt("%s\n", store->printStorePath(store->addToStore(std::string(baseNameOf(i)), i)));
 }
 
 
 /* Preload the output of a fixed-output derivation into the Nix
    store. */
-static void opAddFixed(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opAddFixed(Strings opFlags, Strings opArgs)
 {
     auto method = FileIngestionMethod::Flat;
 
@@ -210,19 +195,13 @@ static void opAddFixed(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
     HashType hashAlgo = parseHashType(opArgs.front());
     opArgs.pop_front();
 
-    for (auto & i : opArgs) {
-        std::cout << fmt(
-            "%s\n",
-            store->printStorePath(
-                aio.blockOn(store->addToStoreSlow(baseNameOf(i), i, method, hashAlgo)).path
-            )
-        );
-    }
+    for (auto & i : opArgs)
+        std::cout << fmt("%s\n", store->printStorePath(store->addToStoreSlow(baseNameOf(i), i, method, hashAlgo).path));
 }
 
 
 /* Hack to support caching in `nix-prefetch-url'. */
-static void opPrintFixedPath(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opPrintFixedPath(Strings opFlags, Strings opArgs)
 {
     auto method = FileIngestionMethod::Flat;
 
@@ -246,29 +225,29 @@ static void opPrintFixedPath(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static kj::Promise<Result<StorePathSet>> maybeUseOutputs(const StorePath & storePath, bool useOutput, bool forceRealise)
-try {
-    if (forceRealise) TRY_AWAIT(realisePath({storePath}));
+static StorePathSet maybeUseOutputs(const StorePath & storePath, bool useOutput, bool forceRealise)
+{
+    if (forceRealise) realisePath({storePath});
     if (useOutput && storePath.isDerivation()) {
-        auto drv = TRY_AWAIT(store->derivationFromPath(storePath));
+        auto drv = store->derivationFromPath(storePath);
         StorePathSet outputs;
         if (forceRealise)
-            co_return TRY_AWAIT(store->queryDerivationOutputs(storePath));
-        for (auto & i : drv.outputsAndPaths(*store)) {
-            outputs.insert(i.second.second);
+            return store->queryDerivationOutputs(storePath);
+        for (auto & i : drv.outputsAndOptPaths(*store)) {
+            if (!i.second.second)
+                throw UsageError("Cannot use output path of floating content-addressed derivation until we know what it is (e.g. by building it)");
+            outputs.insert(*i.second.second);
         }
-        co_return outputs;
+        return outputs;
     }
-    else co_return StorePathSet{storePath};
-} catch (...) {
-    co_return result::current_exception();
+    else return {storePath};
 }
 
 
 /* Some code to print a tree representation of a derivation dependency
    graph.  Topological sorting is used to keep the tree relatively
    flat. */
-static void printTree(AsyncIoRoot & aio, const StorePath & path,
+static void printTree(const StorePath & path,
     const std::string & firstPad, const std::string & tailPad, StorePathSet & done)
 {
     if (!done.insert(path).second) {
@@ -278,18 +257,18 @@ static void printTree(AsyncIoRoot & aio, const StorePath & path,
 
     cout << fmt("%s%s\n", firstPad, store->printStorePath(path));
 
-    auto info = aio.blockOn(store->queryPathInfo(path));
+    auto info = store->queryPathInfo(path);
 
     /* Topologically sort under the relation A < B iff A \in
        closure(B).  That is, if derivation A is an (possibly indirect)
        input of B, then A is printed first.  This has the effect of
        flattening the tree, preventing deeply nested structures.  */
-    auto sorted = aio.blockOn(store->topoSortPaths(info->references));
+    auto sorted = store->topoSortPaths(info->references);
     reverse(sorted.begin(), sorted.end());
 
     for (const auto &[n, i] : enumerate(sorted)) {
         bool last = n + 1 == sorted.size();
-        printTree(aio, i,
+        printTree(i,
             tailPad + (last ? treeLast : treeConn),
             tailPad + (last ? treeNull : treeLine),
             done);
@@ -298,7 +277,7 @@ static void printTree(AsyncIoRoot & aio, const StorePath & path,
 
 
 /* Perform various sorts of queries. */
-static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opQuery(Strings opFlags, Strings opArgs)
 {
     enum QueryType
         { qOutputs, qRequisites, qReferences, qReferrers
@@ -349,7 +328,7 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
         case qOutputs: {
             for (auto & i : opArgs) {
-                auto outputs = aio.blockOn(maybeUseOutputs(store->followLinksToStorePath(i), true, forceRealise));
+                auto outputs = maybeUseOutputs(store->followLinksToStorePath(i), true, forceRealise);
                 for (auto & outputPath : outputs)
                     cout << fmt("%1%\n", store->printStorePath(outputPath));
             }
@@ -362,26 +341,23 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         case qReferrersClosure: {
             StorePathSet paths;
             for (auto & i : opArgs) {
-                auto ps = aio.blockOn(maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise));
+                auto ps = maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise);
                 for (auto & j : ps) {
-                    if (query == qRequisites) {
-                        aio.blockOn(store->computeFSClosure(j, paths, false, includeOutputs));
-                    }
+                    if (query == qRequisites) store->computeFSClosure(j, paths, false, includeOutputs);
                     else if (query == qReferences) {
-                        for (auto & p : aio.blockOn(store->queryPathInfo(j))->references)
+                        for (auto & p : store->queryPathInfo(j)->references)
                             paths.insert(p);
                     }
                     else if (query == qReferrers) {
                         StorePathSet tmp;
-                        aio.blockOn(store->queryReferrers(j, tmp));
+                        store->queryReferrers(j, tmp);
                         for (auto & i : tmp)
                             paths.insert(i);
                     }
-                    else if (query == qReferrersClosure)
-                        aio.blockOn(store->computeFSClosure(j, paths, true));
+                    else if (query == qReferrersClosure) store->computeFSClosure(j, paths, true);
                 }
             }
-            auto sorted = aio.blockOn(store->topoSortPaths(paths));
+            auto sorted = store->topoSortPaths(paths);
             for (StorePaths::reverse_iterator i = sorted.rbegin();
                  i != sorted.rend(); ++i)
                 cout << fmt("%s\n", store->printStorePath(*i));
@@ -390,7 +366,7 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
         case qDeriver:
             for (auto & i : opArgs) {
-                auto info = aio.blockOn(store->queryPathInfo(store->followLinksToStorePath(i)));
+                auto info = store->queryPathInfo(store->followLinksToStorePath(i));
                 cout << fmt("%s\n", info->deriver ? store->printStorePath(*info->deriver) : "unknown-deriver");
             }
             break;
@@ -398,13 +374,12 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         case qValidDerivers: {
             StorePathSet result;
             for (auto & i : opArgs) {
-                auto derivers =
-                    aio.blockOn(store->queryValidDerivers(store->followLinksToStorePath(i)));
-                for (const auto & i : derivers) {
+                auto derivers = store->queryValidDerivers(store->followLinksToStorePath(i));
+                for (const auto &i: derivers) {
                     result.insert(i);
                 }
             }
-            auto sorted = aio.blockOn(store->topoSortPaths(result));
+            auto sorted = store->topoSortPaths(result);
             for (StorePaths::reverse_iterator i = sorted.rbegin();
                  i != sorted.rend(); ++i)
                 cout << fmt("%s\n", store->printStorePath(*i));
@@ -413,8 +388,8 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
         case qBinding:
             for (auto & i : opArgs) {
-                auto path = aio.blockOn(useDeriver(store->followLinksToStorePath(i)));
-                Derivation drv = aio.blockOn(store->derivationFromPath(path));
+                auto path = useDeriver(store->followLinksToStorePath(i));
+                Derivation drv = store->derivationFromPath(path);
                 StringPairs::iterator j = drv.env.find(bindingName);
                 if (j == drv.env.end())
                     throw Error("derivation '%s' has no environment binding named '%s'",
@@ -426,8 +401,8 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         case qHash:
         case qSize:
             for (auto & i : opArgs) {
-                for (auto & j : aio.blockOn(maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise))) {
-                    auto info = aio.blockOn(store->queryPathInfo(j));
+                for (auto & j : maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise)) {
+                    auto info = store->queryPathInfo(j);
                     if (query == qHash) {
                         assert(info->narHash.type == HashType::SHA256);
                         cout << fmt("%s\n", info->narHash.to_string(Base::Base32, true));
@@ -440,25 +415,25 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         case qTree: {
             StorePathSet done;
             for (auto & i : opArgs)
-                printTree(aio, store->followLinksToStorePath(i), "", "", done);
+                printTree(store->followLinksToStorePath(i), "", "", done);
             break;
         }
 
         case qGraph: {
             StorePathSet roots;
             for (auto & i : opArgs)
-                for (auto & j : aio.blockOn(maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise)))
+                for (auto & j : maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise))
                     roots.insert(j);
-            aio.blockOn(printDotGraph(ref<Store>::unsafeFromPtr(store), std::move(roots)));
+            printDotGraph(ref<Store>(store), std::move(roots));
             break;
         }
 
         case qGraphML: {
             StorePathSet roots;
             for (auto & i : opArgs)
-                for (auto & j : aio.blockOn(maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise)))
+                for (auto & j : maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise))
                     roots.insert(j);
-            aio.blockOn(printGraphML(ref<Store>::unsafeFromPtr(store), std::move(roots)));
+            printGraphML(ref<Store>(store), std::move(roots));
             break;
         }
 
@@ -471,15 +446,15 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         case qRoots: {
             StorePathSet args;
             for (auto & i : opArgs)
-                for (auto & p : aio.blockOn(maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise)))
+                for (auto & p : maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise))
                     args.insert(p);
 
             StorePathSet referrers;
-            aio.blockOn(store->computeFSClosure(
-                args, referrers, true, settings.gcKeepOutputs, settings.gcKeepDerivations));
+            store->computeFSClosure(
+                args, referrers, true, settings.gcKeepOutputs, settings.gcKeepDerivations);
 
             auto & gcStore = require<GcStore>(*store);
-            Roots roots = aio.blockOn(gcStore.findRoots(false));
+            Roots roots = gcStore.findRoots(false);
             for (auto & [target, links] : roots)
                 if (referrers.find(target) != referrers.end())
                     for (auto & link : links)
@@ -493,13 +468,13 @@ static void opQuery(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static void opPrintEnv(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opPrintEnv(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
     if (opArgs.size() != 1) throw UsageError("'--print-env' requires one derivation store path");
 
     Path drvPath = opArgs.front();
-    Derivation drv = aio.blockOn(store->derivationFromPath(store->parseStorePath(drvPath)));
+    Derivation drv = store->derivationFromPath(store->parseStorePath(drvPath));
 
     /* Print each environment variable in the derivation in a format
      * that can be sourced by the shell. */
@@ -519,7 +494,7 @@ static void opPrintEnv(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static void opReadLog(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opReadLog(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
 
@@ -529,7 +504,7 @@ static void opReadLog(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
     for (auto & i : opArgs) {
         auto path = logStore.followLinksToStorePath(i);
-        auto log = aio.blockOn(logStore.getBuildLog(path));
+        auto log = logStore.getBuildLog(path);
         if (!log)
             throw Error("build log of derivation '%s' is not available", logStore.printStorePath(path));
         std::cout << *log;
@@ -537,23 +512,20 @@ static void opReadLog(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static void opDumpDB(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opDumpDB(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
     if (!opArgs.empty()) {
-        for (auto & i : opArgs) {
-            cout << aio.blockOn(
-                store->makeValidityRegistration({store->followLinksToStorePath(i)}, true, true)
-            );
-        }
+        for (auto & i : opArgs)
+            cout << store->makeValidityRegistration({store->followLinksToStorePath(i)}, true, true);
     } else {
-        for (auto & i : aio.blockOn(store->queryAllValidPaths()))
-            cout << aio.blockOn(store->makeValidityRegistration({i}, true, true));
+        for (auto & i : store->queryAllValidPaths())
+            cout << store->makeValidityRegistration({i}, true, true);
     }
 }
 
 
-static void registerValidity(AsyncIoRoot & aio, bool reregister, bool hashGiven, bool canonicalise)
+static void registerValidity(bool reregister, bool hashGiven, bool canonicalise)
 {
     ValidPathInfos infos;
 
@@ -563,7 +535,7 @@ static void registerValidity(AsyncIoRoot & aio, bool reregister, bool hashGiven,
         auto hashResultOpt = !hashGiven ? std::optional<HashResult> { {Hash::dummy, -1} } : std::nullopt;
         auto info = decodeValidPathInfo(*store, cin, hashResultOpt);
         if (!info) break;
-        if (!aio.blockOn(store->isValidPath(info->path)) || reregister) {
+        if (!store->isValidPath(info->path) || reregister) {
             /* !!! races */
             if (canonicalise)
                 canonicalisePathMetaData(store->printStorePath(info->path), {});
@@ -576,20 +548,20 @@ static void registerValidity(AsyncIoRoot & aio, bool reregister, bool hashGiven,
         }
     }
 
-    aio.blockOn(ensureLocalStore()->registerValidPaths(infos));
+    ensureLocalStore()->registerValidPaths(infos);
 }
 
 
-static void opLoadDB(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opLoadDB(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
     if (!opArgs.empty())
         throw UsageError("no arguments expected");
-    registerValidity(aio, true, true, false);
+    registerValidity(true, true, false);
 }
 
 
-static void opRegisterValidity(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opRegisterValidity(Strings opFlags, Strings opArgs)
 {
     bool reregister = false; // !!! maybe this should be the default
     bool hashGiven = false;
@@ -601,11 +573,11 @@ static void opRegisterValidity(AsyncIoRoot & aio, Strings opFlags, Strings opArg
 
     if (!opArgs.empty()) throw UsageError("no arguments expected");
 
-    registerValidity(aio, reregister, hashGiven, true);
+    registerValidity(reregister, hashGiven, true);
 }
 
 
-static void opCheckValidity(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opCheckValidity(Strings opFlags, Strings opArgs)
 {
     bool printInvalid = false;
 
@@ -615,7 +587,7 @@ static void opCheckValidity(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
     for (auto & i : opArgs) {
         auto path = store->followLinksToStorePath(i);
-        if (!aio.blockOn(store->isValidPath(path))) {
+        if (!store->isValidPath(path)) {
             if (printInvalid)
                 cout << fmt("%s\n", store->printStorePath(path));
             else
@@ -625,7 +597,7 @@ static void opCheckValidity(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static void opGC(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opGC(Strings opFlags, Strings opArgs)
 {
     bool printRoots = false;
     GCOptions options;
@@ -647,7 +619,7 @@ static void opGC(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
     auto & gcStore = require<GcStore>(*store);
 
     if (printRoots) {
-        Roots roots = aio.blockOn(gcStore.findRoots(false));
+        Roots roots = gcStore.findRoots(false);
         std::set<std::pair<Path, StorePath>> roots2;
         // Transpose and sort the roots.
         for (auto & [target, links] : roots)
@@ -659,7 +631,7 @@ static void opGC(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
     else {
         PrintFreed freed(options.action == GCOptions::gcDeleteDead, results);
-        aio.blockOn(gcStore.collectGarbage(options, results));
+        gcStore.collectGarbage(options, results);
 
         if (options.action != GCOptions::gcDeleteDead)
             for (auto & i : results.paths)
@@ -671,37 +643,28 @@ static void opGC(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 /* Remove paths from the Nix store if possible (i.e., if they do not
    have any remaining referrers and are not reachable from any GC
    roots). */
-static void opDelete(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opDelete(Strings opFlags, Strings opArgs)
 {
     GCOptions options;
     options.action = GCOptions::gcDeleteSpecific;
-    bool deleteClosure = false;
 
     for (auto & i : opFlags)
         if (i == "--ignore-liveness") options.ignoreLiveness = true;
-        else if (i == "--skip-live") options.action = GCOptions::gcTryDeleteSpecific;
-        else if (i == "--delete-closure") deleteClosure = true;
         else throw UsageError("unknown flag '%1%'", i);
 
-    for (auto & arg : opArgs) {
-        StorePath path = store->followLinksToStorePath(arg);
-        if (deleteClosure) {
-            aio.blockOn(store->computeFSClosure(path, options.pathsToDelete));
-        } else {
-            options.pathsToDelete.insert(path);
-        }
-    }
+    for (auto & i : opArgs)
+        options.pathsToDelete.insert(store->followLinksToStorePath(i));
 
     auto & gcStore = require<GcStore>(*store);
 
     GCResults results;
     PrintFreed freed(true, results);
-    aio.blockOn(gcStore.collectGarbage(options, results));
+    gcStore.collectGarbage(options, results);
 }
 
 
 /* Dump a path as a Nix archive.  The archive is written to stdout */
-static void opDump(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opDump(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
     if (opArgs.size() != 1) throw UsageError("only one argument allowed");
@@ -714,7 +677,7 @@ static void opDump(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
 
 /* Restore a value from a Nix archive.  The archive is read from stdin. */
-static void opRestore(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opRestore(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
     if (opArgs.size() != 1) throw UsageError("only one argument allowed");
@@ -724,7 +687,7 @@ static void opRestore(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static void opExport(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opExport(Strings opFlags, Strings opArgs)
 {
     for (auto & i : opFlags)
         throw UsageError("unknown flag '%1%'", i);
@@ -735,12 +698,12 @@ static void opExport(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         paths.insert(store->followLinksToStorePath(i));
 
     FdSink sink(STDOUT_FILENO);
-    aio.blockOn(store->exportPaths(paths, sink));
+    store->exportPaths(paths, sink);
     sink.flush();
 }
 
 
-static void opImport(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opImport(Strings opFlags, Strings opArgs)
 {
     for (auto & i : opFlags)
         throw UsageError("unknown flag '%1%'", i);
@@ -748,7 +711,7 @@ static void opImport(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
     if (!opArgs.empty()) throw UsageError("no arguments expected");
 
     FdSource source(STDIN_FILENO);
-    auto paths = aio.blockOn(store->importPaths(source, NoCheckSigs));
+    auto paths = store->importPaths(source, NoCheckSigs);
 
     for (auto & i : paths)
         cout << fmt("%s\n", store->printStorePath(i)) << std::flush;
@@ -756,7 +719,7 @@ static void opImport(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
 
 /* Initialise the Nix databases. */
-static void opInit(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opInit(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty()) throw UsageError("unknown flag");
     if (!opArgs.empty())
@@ -767,7 +730,7 @@ static void opInit(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
 
 /* Verify the consistency of the Nix environment. */
-static void opVerify(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opVerify(Strings opFlags, Strings opArgs)
 {
     if (!opArgs.empty())
         throw UsageError("no arguments expected");
@@ -780,7 +743,7 @@ static void opVerify(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
         else if (i == "--repair") repair = Repair;
         else throw UsageError("unknown flag '%1%'", i);
 
-    if (aio.blockOn(store->verifyStore(checkContents, repair))) {
+    if (store->verifyStore(checkContents, repair)) {
         warn("not all store errors were fixed");
         throw Exit(1);
     }
@@ -788,7 +751,7 @@ static void opVerify(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
 
 /* Verify whether the contents of the given store path have not changed. */
-static void opVerifyPath(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opVerifyPath(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty())
         throw UsageError("no flags expected");
@@ -798,15 +761,15 @@ static void opVerifyPath(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
     for (auto & i : opArgs) {
         auto path = store->followLinksToStorePath(i);
         printMsg(lvlTalkative, "checking path '%s'...", store->printStorePath(path));
-        auto info = aio.blockOn(store->queryPathInfo(path));
+        auto info = store->queryPathInfo(path);
         HashSink sink(info->narHash.type);
-        aio.blockOn(store->narFromPath(path))->drainInto(sink);
+        sink << store->narFromPath(path);
         auto current = sink.finish();
         if (current.first != info->narHash) {
             printError("path '%s' was modified! expected hash '%s', got '%s'",
                 store->printStorePath(path),
-                info->narHash.to_string(Base::SRI, true),
-                current.first.to_string(Base::SRI, true));
+                info->narHash.to_string(Base::Base32, true),
+                current.first.to_string(Base::Base32, true));
             status = 1;
         }
     }
@@ -817,27 +780,27 @@ static void opVerifyPath(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
 /* Repair the contents of the given path by redownloading it using a
    substituter (if available). */
-static void opRepairPath(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opRepairPath(Strings opFlags, Strings opArgs)
 {
     if (!opFlags.empty())
         throw UsageError("no flags expected");
 
     for (auto & i : opArgs)
-        aio.blockOn(store->repairPath(store->followLinksToStorePath(i)));
+        store->repairPath(store->followLinksToStorePath(i));
 }
 
 /* Optimise the disk space usage of the Nix store by hard-linking
    files with the same contents. */
-static void opOptimise(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opOptimise(Strings opFlags, Strings opArgs)
 {
     if (!opArgs.empty() || !opFlags.empty())
         throw UsageError("no arguments expected");
 
-    aio.blockOn(store->optimiseStore());
+    store->optimiseStore();
 }
 
 /* Serve the nix store in a way usable by a restricted ssh user. */
-static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opServe(Strings opFlags, Strings opArgs)
 {
     bool writeAllowed = false;
     for (auto & i : opFlags)
@@ -910,13 +873,13 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
                 auto paths = ServeProto::Serialise<StorePathSet>::read(*store, rconn);
                 if (lock && writeAllowed)
                     for (auto & path : paths)
-                        aio.blockOn(store->addTempRoot(path));
+                        store->addTempRoot(path);
 
                 if (substitute && writeAllowed) {
-                    aio.blockOn(store->substitutePaths(paths));
+                    store->substitutePaths(paths);
                 }
 
-                auto valid = aio.blockOn(store->queryValidPaths(paths));
+                auto valid = store->queryValidPaths(paths);
                 out << ServeProto::write(*store, wconn, valid);
                 break;
             }
@@ -926,7 +889,7 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
                 // !!! Maybe we want a queryPathInfos?
                 for (auto & i : paths) {
                     try {
-                        auto info = aio.blockOn(store->queryPathInfo(i));
+                        auto info = store->queryPathInfo(i);
                         out << store->printStorePath(info->path);
                         out << ServeProto::write(*store, wconn, static_cast<const UnkeyedValidPathInfo &>(*info));
                     } catch (InvalidPath &) {
@@ -937,22 +900,19 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
             }
 
             case ServeProto::Command::DumpStorePath:
-                aio.blockOn(store->narFromPath(store->parseStorePath(readString(in))))
-                    ->drainInto(out);
+                out << store->narFromPath(store->parseStorePath(readString(in)));
                 break;
 
             case ServeProto::Command::ImportPaths: {
                 if (!writeAllowed) throw Error("importing paths is not allowed");
-                aio.blockOn(store->importPaths(in, NoCheckSigs)); // FIXME: should we skip sig checking?
+                store->importPaths(in, NoCheckSigs); // FIXME: should we skip sig checking?
                 out << 1; // indicate success
                 break;
             }
 
             case ServeProto::Command::ExportPaths: {
                 readInt(in); // obsolete
-                aio.blockOn(store->exportPaths(
-                    ServeProto::Serialise<StorePathSet>::read(*store, rconn), out
-                ));
+                store->exportPaths(ServeProto::Serialise<StorePathSet>::read(*store, rconn), out);
                 break;
             }
 
@@ -968,7 +928,7 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 
                 try {
                     MonitorFdHup monitor(in.fd);
-                    aio.blockOn(store->buildPaths(toDerivedPaths(paths)));
+                    store->buildPaths(toDerivedPaths(paths));
                     out << 0;
                 } catch (Error & e) {
                     assert(e.info().status);
@@ -988,7 +948,7 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
                 getBuildSettings();
 
                 MonitorFdHup monitor(in.fd);
-                auto status = aio.blockOn(store->buildDerivation(drvPath, drv));
+                auto status = store->buildDerivation(drvPath, drv);
 
                 out << ServeProto::write(*store, wconn, status);
                 break;
@@ -997,12 +957,8 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
             case ServeProto::Command::QueryClosure: {
                 bool includeOutputs = readInt(in);
                 StorePathSet closure;
-                aio.blockOn(store->computeFSClosure(
-                    ServeProto::Serialise<StorePathSet>::read(*store, rconn),
-                    closure,
-                    false,
-                    includeOutputs
-                ));
+                store->computeFSClosure(ServeProto::Serialise<StorePathSet>::read(*store, rconn),
+                    closure, false, includeOutputs);
                 out << ServeProto::write(*store, wconn, closure);
                 break;
             }
@@ -1027,9 +983,8 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
                     throw Error("narInfo is too old and missing the narSize field");
 
                 SizedSource sizedSource(in, info.narSize);
-                AsyncSourceInputStream stream{sizedSource};
 
-                aio.blockOn(store->addToStore(info, stream, NoRepair, NoCheckSigs));
+                store->addToStore(info, sizedSource, NoRepair, NoCheckSigs);
 
                 // consume all the data that has been sent before continuing.
                 sizedSource.drainAll();
@@ -1048,7 +1003,7 @@ static void opServe(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 }
 
 
-static void opGenerateBinaryCacheKey(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opGenerateBinaryCacheKey(Strings opFlags, Strings opArgs)
 {
     for (auto & i : opFlags)
         throw UsageError("unknown flag '%1%'", i);
@@ -1067,7 +1022,7 @@ static void opGenerateBinaryCacheKey(AsyncIoRoot & aio, Strings opFlags, Strings
 }
 
 
-static void opVersion(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
+static void opVersion(Strings opFlags, Strings opArgs)
 {
     printVersion("nix-store");
 }
@@ -1076,7 +1031,7 @@ static void opVersion(AsyncIoRoot & aio, Strings opFlags, Strings opArgs)
 /* Scan the arguments; find the operation, set global flags, put all
    other flags in a list, and put all other arguments in another
    list. */
-static int main_nix_store(AsyncIoRoot & aio, std::string programName, Strings argv)
+static int main_nix_store(std::string programName, Strings argv)
 {
     {
         Strings opFlags, opArgs;
@@ -1085,7 +1040,7 @@ static int main_nix_store(AsyncIoRoot & aio, std::string programName, Strings ar
         std::string opName;
         bool showHelp = false;
 
-        LegacyArgs(aio, programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
+        LegacyArgs(programName, [&](Strings::iterator & arg, const Strings::iterator & end) {
             Operation oldOp = op;
 
             if (*arg == "--help")
@@ -1213,16 +1168,16 @@ static int main_nix_store(AsyncIoRoot & aio, std::string programName, Strings ar
         if (!op) throw UsageError("no operation specified");
 
         if (op != opDump && op != opRestore) /* !!! hack */
-            store = aio.blockOn(openStore());
+            store = openStore();
 
-        op(aio, std::move(opFlags), std::move(opArgs));
+        op(std::move(opFlags), std::move(opArgs));
 
         return 0;
     }
 }
 
-void registerLegacyNixStore() {
-    LegacyCommandRegistry::add("nix-store", main_nix_store);
+void registerNixStore() {
+    LegacyCommands::add("nix-store", main_nix_store);
 }
 
 }

lix/legacy/nix-store.hh

@@ -3,6 +3,6 @@
 
 namespace nix {
 
-void registerLegacyNixStore();
+void registerNixStore();
 
 }

lix/legacy/user-env.cc

@@ -3,8 +3,10 @@
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/path-with-outputs.hh"
 #include "lix/libstore/local-fs-store.hh"
+#include "lix/libstore/globals.hh"
 #include "lix/libmain/shared.hh"
 #include "lix/libexpr/eval.hh"
+#include "lix/libexpr/eval-inline.hh"
 #include "lix/libstore/profiles.hh"
 #include "lix/libexpr/print-ambiguous.hh"
 
@@ -26,9 +28,9 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
             drvsToBuild.push_back({*drvPath});
 
     debug("building user environment dependencies");
-    state.aio.blockOn(state.ctx.store->buildPaths(
+    state.ctx.store->buildPaths(
         toDerivedPaths(drvsToBuild),
-        state.ctx.repair ? bmRepair : bmNormal));
+        state.ctx.repair ? bmRepair : bmNormal);
 
     /* Construct the whole top level derivation. */
     StorePathSet references;
@@ -64,8 +66,8 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
 
             /* This is only necessary when installing store paths, e.g.,
                `nix-env -i /nix/store/abcd...-foo'. */
-            state.aio.blockOn(state.ctx.store->addTempRoot(*j.second));
-            state.aio.blockOn(state.ctx.store->ensurePath(*j.second));
+            state.ctx.store->addTempRoot(*j.second);
+            state.ctx.store->ensurePath(*j.second);
 
             references.insert(*j.second);
         }
@@ -90,8 +92,8 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
        environment. */
     std::ostringstream str;
     printAmbiguous(manifest, state.ctx.symbols, str, nullptr, std::numeric_limits<int>::max());
-    auto manifestFile = state.aio.blockOn(state.ctx.store->addTextToStore("env-manifest.nix",
-        str.str(), references));
+    auto manifestFile = state.ctx.store->addTextToStore("env-manifest.nix",
+        str.str(), references);
 
     /* Get the environment builder expression. */
     Value envBuilder;
@@ -112,7 +114,7 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
 
     /* Evaluate it. */
     debug("evaluating user environment builder");
-    state.forceValue(topLevel, noPos);
+    state.forceValue(topLevel, topLevel.determinePos(noPos));
     NixStringContext context;
     Attr & aDrvPath(*topLevel.attrs->find(state.ctx.s.drvPath));
     auto topLevelDrv = state.coerceToStorePath(aDrvPath.pos, *aDrvPath.value, context, "");
@@ -123,15 +125,16 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
     debug("building user environment");
     std::vector<StorePathWithOutputs> topLevelDrvs;
     topLevelDrvs.push_back({topLevelDrv});
-    state.aio.blockOn(state.ctx.store->buildPaths(
+    state.ctx.store->buildPaths(
         toDerivedPaths(topLevelDrvs),
-        state.ctx.repair ? bmRepair : bmNormal));
+        state.ctx.repair ? bmRepair : bmNormal);
 
     /* Switch the current user environment to the output path. */
-    auto store2 = state.ctx.store.try_cast_shared<LocalFSStore>();
+    auto store2 = state.ctx.store.dynamic_pointer_cast<LocalFSStore>();
 
     if (store2) {
-        PathLock lock = lockProfile(profile);
+        PathLocks lock;
+        lockProfile(lock, profile);
 
         Path lockTokenCur = optimisticLockProfile(profile);
         if (lockToken != lockTokenCur) {
@@ -140,7 +143,7 @@ bool createUserEnv(EvalState & state, DrvInfos & elems,
         }
 
         debug("switching to new user environment");
-        Path generation = state.aio.blockOn(createGeneration(*store2, profile, topLevelOut));
+        Path generation = createGeneration(*store2, profile, topLevelOut);
         switchLink(profile, generation);
     }
 

lix/libcmd/built-path.cc

@@ -1,11 +1,10 @@
 #include "lix/libcmd/built-path.hh"
 #include "lix/libstore/derivations.hh"
 #include "lix/libstore/store-api.hh"
-#include "lix/libutil/async.hh"
-#include "lix/libutil/json.hh"
-#include "lix/libutil/result.hh"
 
-#include <kj/async.h>
+#include <nlohmann/json.hpp>
+
+#include <optional>
 
 namespace nix {
 
@@ -13,9 +12,9 @@ namespace nix {
     bool MY_TYPE ::operator COMPARATOR (const MY_TYPE & other) const \
     { \
         const MY_TYPE* me = this; \
-        auto fields1 = std::tie(me->drvPath, me->FIELD); \
+        auto fields1 = std::tie(*me->drvPath, me->FIELD); \
         me = &other; \
-        auto fields2 = std::tie(me->drvPath, me->FIELD); \
+        auto fields2 = std::tie(*me->drvPath, me->FIELD); \
         return fields1 COMPARATOR fields2; \
     }
 #define CMP(CHILD_TYPE, MY_TYPE, FIELD) \
@@ -23,6 +22,10 @@ namespace nix {
     CMP_ONE(CHILD_TYPE, MY_TYPE, FIELD, !=) \
     CMP_ONE(CHILD_TYPE, MY_TYPE, FIELD, <)
 
+#define FIELD_TYPE std::pair<std::string, StorePath>
+CMP(SingleBuiltPath, SingleBuiltPathBuilt, output)
+#undef FIELD_TYPE
+
 #define FIELD_TYPE std::map<std::string, StorePath>
 CMP(SingleBuiltPath, BuiltPathBuilt, outputs)
 #undef FIELD_TYPE
@@ -30,6 +33,16 @@ CMP(SingleBuiltPath, BuiltPathBuilt, outputs)
 #undef CMP
 #undef CMP_ONE
 
+StorePath SingleBuiltPath::outPath() const
+{
+    return std::visit(
+        overloaded{
+            [](const SingleBuiltPath::Opaque & p) { return p.path; },
+            [](const SingleBuiltPath::Built & b) { return b.output.second; },
+        }, raw()
+    );
+}
+
 StorePathSet BuiltPath::outPaths() const
 {
     return std::visit(
@@ -45,51 +58,92 @@ StorePathSet BuiltPath::outPaths() const
     );
 }
 
-kj::Promise<Result<JSON>> BuiltPath::Built::toJSON(const Store & store) const
-try {
-    JSON res;
-    res["drvPath"] = TRY_AWAIT(drvPath.toJSON(store));
+SingleDerivedPath::Built SingleBuiltPath::Built::discardOutputPath() const
+{
+    return SingleDerivedPath::Built {
+        .drvPath = make_ref<SingleDerivedPath>(drvPath->discardOutputPath()),
+        .output = output.first,
+    };
+}
+
+SingleDerivedPath SingleBuiltPath::discardOutputPath() const
+{
+    return std::visit(
+        overloaded{
+            [](const SingleBuiltPath::Opaque & p) -> SingleDerivedPath {
+                return p;
+            },
+            [](const SingleBuiltPath::Built & b) -> SingleDerivedPath {
+                return b.discardOutputPath();
+            },
+        }, raw()
+    );
+}
+
+nlohmann::json BuiltPath::Built::toJSON(const Store & store) const
+{
+    nlohmann::json res;
+    res["drvPath"] = drvPath->toJSON(store);
     for (const auto & [outputName, outputPath] : outputs) {
         res["outputs"][outputName] = store.printStorePath(outputPath);
     }
-    co_return res;
-} catch (...) {
-    co_return result::current_exception();
+    return res;
 }
 
+nlohmann::json SingleBuiltPath::Built::toJSON(const Store & store) const
+{
+    nlohmann::json res;
+    res["drvPath"] = drvPath->toJSON(store);
+    auto & [outputName, outputPath] = output;
+    res["output"] = outputName;
+    res["outputPath"] = store.printStorePath(outputPath);
+    return res;
+}
 
-kj::Promise<Result<RealisedPath::Set>> BuiltPath::toRealisedPaths(Store & store) const
-try {
+nlohmann::json SingleBuiltPath::toJSON(const Store & store) const
+{
+    return std::visit([&](const auto & buildable) {
+        return buildable.toJSON(store);
+    }, raw());
+}
+
+nlohmann::json BuiltPath::toJSON(const Store & store) const
+{
+    return std::visit([&](const auto & buildable) {
+        return buildable.toJSON(store);
+    }, raw());
+}
+
+RealisedPath::Set BuiltPath::toRealisedPaths(Store & store) const
+{
     RealisedPath::Set res;
-    auto handlers = overloaded{
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        [&](const BuiltPath::Opaque & p) -> kj::Promise<Result<void>> {
-            try {
-                res.insert(p.path);
-                return {result::success()};
-            } catch (...) {
-                return {result::current_exception()};
-            }
-        },
-        // NOLINTNEXTLINE(cppcoreguidelines-avoid-capturing-lambda-coroutines)
-        [&](const BuiltPath::Built & p) -> kj::Promise<Result<void>> {
-            try {
-                auto drvHashes = TRY_AWAIT(
-                    staticOutputHashes(store, TRY_AWAIT(store.readDerivation(p.drvPath.path)))
-                );
+    std::visit(
+        overloaded{
+            [&](const BuiltPath::Opaque & p) { res.insert(p.path); },
+            [&](const BuiltPath::Built & p) {
+                auto drvHashes =
+                    staticOutputHashes(store, store.readDerivation(p.drvPath->outPath()));
                 for (auto& [outputName, outputPath] : p.outputs) {
-                    res.insert(outputPath);
+                    if (experimentalFeatureSettings.isEnabled(
+                                Xp::CaDerivations)) {
+                        auto drvOutput = get(drvHashes, outputName);
+                        if (!drvOutput)
+                            throw Error(
+                                "the derivation '%s' has unrealised output '%s' (derived-path.cc/toRealisedPaths)",
+                                store.printStorePath(p.drvPath->outPath()), outputName);
+                        auto thisRealisation = store.queryRealisation(
+                            DrvOutput{*drvOutput, outputName});
+                        assert(thisRealisation);  // We’ve built it, so we must
+                                                  // have the realisation
+                        res.insert(*thisRealisation);
+                    } else {
+                        res.insert(outputPath);
+                    }
                 }
-                co_return result::success();
-            } catch (...) {
-                co_return result::current_exception();
-            }
+            },
         },
-    };
-    TRY_AWAIT(std::visit(handlers, raw()));
-    co_return res;
-} catch (...) {
-    co_return result::current_exception();
+        raw());
+    return res;
 }
 
 }

lix/libcmd/built-path.hh

@@ -2,21 +2,67 @@
 ///@file
 #include "lix/libstore/derived-path.hh"
 #include "lix/libstore/realisation.hh"
-#include "lix/libutil/result.hh"
-#include <kj/async.h>
 
 namespace nix {
 
+struct SingleBuiltPath;
+
+struct SingleBuiltPathBuilt {
+    ref<SingleBuiltPath> drvPath;
+    std::pair<std::string, StorePath> output;
+
+    SingleDerivedPathBuilt discardOutputPath() const;
+
+    std::string to_string(const Store & store) const;
+    static SingleBuiltPathBuilt parse(const Store & store, std::string_view, std::string_view);
+    nlohmann::json toJSON(const Store & store) const;
+
+    DECLARE_CMP(SingleBuiltPathBuilt);
+};
+
+namespace built_path::detail {
+using SingleBuiltPathRaw = std::variant<
+    DerivedPathOpaque,
+    SingleBuiltPathBuilt
+>;
+}
+
+struct SingleBuiltPath : built_path::detail::SingleBuiltPathRaw {
+    using Raw = built_path::detail::SingleBuiltPathRaw;
+    using Raw::Raw;
+
+    using Opaque = DerivedPathOpaque;
+    using Built = SingleBuiltPathBuilt;
+
+    inline const Raw & raw() const {
+        return static_cast<const Raw &>(*this);
+    }
+
+    StorePath outPath() const;
+
+    SingleDerivedPath discardOutputPath() const;
+
+    static SingleBuiltPath parse(const Store & store, std::string_view);
+    nlohmann::json toJSON(const Store & store) const;
+};
+
+static inline ref<SingleBuiltPath> staticDrv(StorePath drvPath)
+{
+    return make_ref<SingleBuiltPath>(SingleBuiltPath::Opaque { drvPath });
+}
+
 /**
  * A built derived path with hints in the form of optional concrete output paths.
  *
  * See 'BuiltPath' for more an explanation.
  */
 struct BuiltPathBuilt {
-    DerivedPathOpaque drvPath;
+    ref<SingleBuiltPath> drvPath;
     std::map<std::string, StorePath> outputs;
 
-    kj::Promise<Result<JSON>> toJSON(const Store & store) const;
+    std::string to_string(const Store & store) const;
+    static BuiltPathBuilt parse(const Store & store, std::string_view, std::string_view);
+    nlohmann::json toJSON(const Store & store) const;
 
     DECLARE_CMP(BuiltPathBuilt);
 };
@@ -44,7 +90,9 @@ struct BuiltPath : built_path::detail::BuiltPathRaw {
     }
 
     StorePathSet outPaths() const;
-    kj::Promise<Result<RealisedPath::Set>> toRealisedPaths(Store & store) const;
+    RealisedPath::Set toRealisedPaths(Store & store) const;
+
+    nlohmann::json toJSON(const Store & store) const;
 };
 
 typedef std::vector<BuiltPath> BuiltPaths;

lix/libcmd/cmd-profiles.cc

@@ -3,7 +3,6 @@
 #include "lix/libcmd/cmd-profiles.hh"
 #include "lix/libcmd/built-path.hh"
 #include "lix/libstore/builtins/buildenv.hh"
-#include "lix/libutil/async-io.hh"
 #include "lix/libutil/logging.hh"
 #include "lix/libstore/names.hh"
 #include "lix/libstore/store-api.hh"
@@ -111,7 +110,7 @@ ProfileManifest::ProfileManifest(EvalState & state, const Path & profile)
     auto manifestPath = profile + "/manifest.json";
 
     if (pathExists(manifestPath)) {
-        auto json = json::parse(readFile(manifestPath), "a profile manifest");
+        auto json = nlohmann::json::parse(readFile(manifestPath));
 
         auto version = json.value("version", 0);
         std::string sUrl;
@@ -198,15 +197,15 @@ void ProfileManifest::addElement(ProfileElement element)
     addElement(finalName, std::move(element));
 }
 
-JSON ProfileManifest::toJSON(Store & store) const
+nlohmann::json ProfileManifest::toJSON(Store & store) const
 {
-    auto es = JSON::object();
+    auto es = nlohmann::json::object();
     for (auto & [name, element] : elements) {
-        auto paths = JSON::array();
+        auto paths = nlohmann::json::array();
         for (auto & path : element.storePaths) {
             paths.push_back(store.printStorePath(path));
         }
-        JSON obj;
+        nlohmann::json obj;
         obj["storePaths"] = paths;
         obj["active"] = element.active;
         obj["priority"] = element.priority;
@@ -218,14 +217,14 @@ JSON ProfileManifest::toJSON(Store & store) const
         }
         es[name] = obj;
     }
-    JSON json;
+    nlohmann::json json;
     json["version"] = 3;
     json["elements"] = es;
     return json;
 }
 
-kj::Promise<Result<StorePath>> ProfileManifest::build(ref<Store> store)
-try {
+StorePath ProfileManifest::build(ref<Store> store)
+{
     auto tempDir = createTempDir();
 
     StorePathSet references;
@@ -267,12 +266,10 @@ try {
     };
     info.narSize = sink.s.size();
 
-    AsyncStringInputStream source(sink.s);
-    TRY_AWAIT(store->addToStore(info, source));
+    StringSource source(sink.s);
+    store->addToStore(info, source);
 
-    co_return std::move(info.path);
-} catch (...) {
-    co_return result::current_exception();
+    return std::move(info.path);
 }
 
 void ProfileManifest::printDiff(

lix/libcmd/cmd-profiles.hh

@@ -6,11 +6,14 @@
 #include "lix/libexpr/flake/flakeref.hh"
 #include "lix/libexpr/get-drvs.hh"
 #include "lix/libutil/types.hh"
-#include "lix/libutil/json-fwd.hh"
+#include "lix/libutil/url.hh"
+#include "lix/libutil/url-name.hh"
 
 #include <string>
 #include <set>
 
+#include <nlohmann/json.hpp>
+
 namespace nix
 {
 
@@ -59,9 +62,9 @@ struct ProfileManifest
 
     ProfileManifest(EvalState & state, const Path & profile);
 
-    JSON toJSON(Store & store) const;
+    nlohmann::json toJSON(Store & store) const;
 
-    kj::Promise<Result<StorePath>> build(ref<Store> store);
+    StorePath build(ref<Store> store);
 
     void addElement(std::string_view nameCandidate, ProfileElement element);
     void addElement(ProfileElement element);

lix/libcmd/command.cc

@@ -2,34 +2,29 @@
 #include "lix/libstore/store-api.hh"
 #include "lix/libstore/local-fs-store.hh"
 #include "lix/libstore/derivations.hh"
+#include "lix/libexpr/nixexpr.hh"
 #include "lix/libstore/profiles.hh"
 #include "lix/libcmd/repl.hh"
 
+#include <nlohmann/json.hpp>
+
 extern char * * environ __attribute__((weak));
 
 namespace nix {
 
-CommandRegistry::CommandMap * CommandRegistry::commands = nullptr;
+RegisterCommand::Commands * RegisterCommand::commands = nullptr;
 
-nix::CommandMap CommandRegistry::getCommandsFor(const std::vector<std::string> & prefix)
+nix::Commands RegisterCommand::getCommandsFor(const std::vector<std::string> & prefix)
 {
-    if (!CommandRegistry::commands) {
-        CommandRegistry::commands = new CommandMap;
-    }
-    nix::CommandMap res;
-    for (auto & [name, command] : *CommandRegistry::commands) {
+    nix::Commands res;
+    for (auto & [name, command] : *RegisterCommand::commands)
         if (name.size() == prefix.size() + 1) {
             bool equal = true;
-            for (size_t i = 0; i < prefix.size(); ++i) {
-                if (name[i] != prefix[i]) {
-                    equal = false;
-                }
-            }
-            if (equal) {
+            for (size_t i = 0; i < prefix.size(); ++i)
+                if (name[i] != prefix[i]) equal = false;
+            if (equal)
                 res.insert_or_assign(name[prefix.size()], command);
-            }
         }
-    }
     return res;
 }
 
@@ -41,12 +36,12 @@ ref<Store> StoreCommand::getStore()
 {
     if (!_store)
         _store = createStore();
-    return *_store;
+    return ref<Store>(_store);
 }
 
 ref<Store> StoreCommand::createStore()
 {
-    return aio().blockOn(openStore());
+    return openStore();
 }
 
 void StoreCommand::run()
@@ -73,7 +68,7 @@ CopyCommand::CopyCommand()
 
 ref<Store> CopyCommand::createStore()
 {
-    return srcUri.empty() ? StoreCommand::createStore() : aio().blockOn(openStore(srcUri));
+    return srcUri.empty() ? StoreCommand::createStore() : openStore(srcUri);
 }
 
 ref<Store> CopyCommand::getDstStore()
@@ -81,7 +76,7 @@ ref<Store> CopyCommand::getDstStore()
     if (srcUri.empty() && dstUri.empty())
         throw UsageError("you must pass '--from' and/or '--to'");
 
-    return aio().blockOn(dstUri.empty() ? openStore() : openStore(dstUri));
+    return dstUri.empty() ? openStore() : openStore(dstUri);
 }
 
 EvalCommand::EvalCommand()
@@ -103,21 +98,21 @@ EvalCommand::~EvalCommand()
 ref<Store> EvalCommand::getEvalStore()
 {
     if (!evalStore)
-        evalStore = evalStoreUrl ? aio().blockOn(openStore(*evalStoreUrl)) : getStore();
-    return *evalStore;
+        evalStore = evalStoreUrl ? openStore(*evalStoreUrl) : getStore();
+    return ref<Store>(evalStore);
 }
 
 ref<eval_cache::CachingEvaluator> EvalCommand::getEvaluator()
 {
     if (!evalState) {
         evalState = std::allocate_shared<eval_cache::CachingEvaluator>(
-            TraceableAllocator<EvalState>(), aio(), searchPath, getEvalStore(), getStore(),
+            TraceableAllocator<EvalState>(), searchPath, getEvalStore(), getStore(),
             startReplOnEvalErrors ? AbstractNixRepl::runSimple : nullptr
         );
 
         evalState->repair = repair;
     }
-    return ref<eval_cache::CachingEvaluator>::unsafeFromPtr(evalState);
+    return ref<eval_cache::CachingEvaluator>(evalState);
 }
 
 MixOperateOnOptions::MixOperateOnOptions()
@@ -164,17 +159,10 @@ void BuiltPathsCommand::run(ref<Store> store, Installables && installables)
         if (installables.size())
             throw UsageError("'--all' does not expect arguments");
         // XXX: Only uses opaque paths, ignores all the realisations
-        for (auto & p : aio().blockOn(store->queryAllValidPaths()))
+        for (auto & p : store->queryAllValidPaths())
             paths.emplace_back(BuiltPath::Opaque{p});
     } else {
-        paths = Installable::toBuiltPaths(
-            *getEvaluator()->begin(aio()),
-            getEvalStore(),
-            store,
-            realiseMode,
-            operateOn,
-            installables
-        );
+        paths = Installable::toBuiltPaths(*getEvaluator()->begin(), getEvalStore(), store, realiseMode, operateOn, installables);
         if (recursive) {
             // XXX: This only computes the store path closure, ignoring
             // intermediate realisations
@@ -183,7 +171,7 @@ void BuiltPathsCommand::run(ref<Store> store, Installables && installables)
                 auto rootFromThis = root.outPaths();
                 pathsRoots.insert(rootFromThis.begin(), rootFromThis.end());
             }
-            aio().blockOn(store->computeFSClosure(pathsRoots, pathsClosure));
+            store->computeFSClosure(pathsRoots, pathsClosure);
             for (auto & path : pathsClosure)
                 paths.emplace_back(BuiltPath::Opaque{path});
         }
@@ -204,7 +192,7 @@ void StorePathsCommand::run(ref<Store> store, BuiltPaths && paths)
         for (auto & p : builtPath.outPaths())
             storePaths.insert(p);
 
-    auto sorted = aio().blockOn(store->topoSortPaths(storePaths));
+    auto sorted = store->topoSortPaths(storePaths);
     std::reverse(sorted.begin(), sorted.end());
 
     run(store, std::move(sorted));
@@ -232,11 +220,11 @@ MixProfile::MixProfile()
 void MixProfile::updateProfile(const StorePath & storePath)
 {
     if (!profile) return;
-    auto store = getStore().try_cast_shared<LocalFSStore>();
+    auto store = getStore().dynamic_pointer_cast<LocalFSStore>();
     if (!store) throw Error("'--profile' is not supported for this Nix store");
     auto profile2 = absPath(*profile);
     switchLink(profile2,
-        aio().blockOn(createGeneration(*store, profile2, storePath)));
+        createGeneration(*store, profile2, storePath));
 }
 
 void MixProfile::updateProfile(const BuiltPaths & buildables)

lix/libcmd/command.hh

@@ -7,7 +7,6 @@
 #include "lix/libcmd/common-eval-args.hh"
 #include "lix/libstore/path.hh"
 #include "lix/libexpr/flake/lockfile.hh"
-#include "lix/libutil/async.hh"
 
 #include <optional>
 
@@ -46,7 +45,7 @@ struct StoreCommand : virtual Command
     virtual void run(ref<Store>) = 0;
 
 private:
-    std::optional<ref<Store>> _store;
+    std::shared_ptr<Store> _store;
 };
 
 /**
@@ -81,7 +80,7 @@ struct EvalCommand : virtual StoreCommand, MixEvalArgs
     virtual ref<eval_cache::CachingEvaluator> getEvaluator();
 
 private:
-    std::optional<ref<Store>> evalStore;
+    std::shared_ptr<Store> evalStore;
 
     std::shared_ptr<eval_cache::CachingEvaluator> evalState;
 };
@@ -262,60 +261,31 @@ struct StorePathCommand : public StorePathsCommand
 /**
  * A helper class for registering \ref Command commands globally.
  */
-struct CommandRegistry
+struct RegisterCommand
 {
-    using CommandMap = std::map<
-        std::vector<std::string>,
-        std::function<ref<Command>(AsyncIoRoot & aio)>
-    >;
-    static CommandMap * commands;
+    typedef std::map<std::vector<std::string>, std::function<ref<Command>()>> Commands;
+    static Commands * commands;
 
-    static void add(std::vector<std::string> && name,
-        std::function<ref<Command>(AsyncIoRoot & aio)> command)
+    RegisterCommand(std::vector<std::string> && name,
+        std::function<ref<Command>()> command)
     {
-        if (!commands) {
-            commands = new CommandMap;
-        }
+        if (!commands) commands = new Commands;
         commands->emplace(name, command);
     }
 
-    static nix::CommandMap getCommandsFor(const std::vector<std::string> & prefix);
-};
-
-template<typename Base>
-class MixAio : public Base
-{
-private:
-    AsyncIoRoot & aio_;
-
-public:
-    template<typename... Args>
-    MixAio(AsyncIoRoot & aio, Args &&... args)
-        : Base(std::forward<Args>(args)...)
-        , aio_(aio)
-    {
-    }
-
-    AsyncIoRoot & aio() override
-    {
-        return aio_;
-    }
+    static nix::Commands getCommandsFor(const std::vector<std::string> & prefix);
 };
 
 template<class T>
-static void registerCommand(const std::string & name)
+static RegisterCommand registerCommand(const std::string & name)
 {
-    CommandRegistry::add({name}, [](AsyncIoRoot & aio) {
-        return make_ref<MixAio<T>>(aio);
-    });
+    return RegisterCommand({name}, [](){ return make_ref<T>(); });
 }
 
 template<class T>
-static void registerCommand2(std::vector<std::string> && name)
+static RegisterCommand registerCommand2(std::vector<std::string> && name)
 {
-    CommandRegistry::add(std::move(name), [](AsyncIoRoot & aio) {
-        return make_ref<MixAio<T>>(aio);
-    });
+    return RegisterCommand(std::move(name), [](){ return make_ref<T>(); });
 }
 
 struct MixProfile : virtual StoreCommand
@@ -360,9 +330,7 @@ void completeFlakeInputPath(
     const std::vector<FlakeRef> & flakeRefs,
     std::string_view prefix);
 
-void completeFlakeRef(
-    AsyncIoRoot & aio, AddCompletions & completions, ref<Store> store, std::string_view prefix
-);
+void completeFlakeRef(AddCompletions & completions, ref<Store> store, std::string_view prefix);
 
 void completeFlakeRefWithFragment(
     AddCompletions & completions,
@@ -373,11 +341,10 @@ void completeFlakeRefWithFragment(
     const Strings & defaultFlakeAttrPaths,
     std::string_view prefix);
 
-kj::Promise<Result<void>> printClosureDiff(
+void printClosureDiff(
     ref<Store> store,
     const StorePath & beforePath,
     const StorePath & afterPath,
-    bool json,
     std::string_view indent);
 
 }

lix/libcmd/common-eval-args.cc

@@ -8,14 +8,12 @@
 #include "lix/libexpr/flake/flakeref.hh"
 #include "lix/libstore/store-api.hh"
 #include "lix/libcmd/command.hh"
-#include "lix/libutil/async.hh"
-#include "lix/libutil/regex.hh"
 
 #include <regex>
 
 namespace nix {
 
-static std::regex const identifierRegex = regex::parse("^[A-Za-z_][A-Za-z0-9_'-]*$");
+static std::regex const identifierRegex("^[A-Za-z_][A-Za-z0-9_'-]*$");
 static void warnInvalidNixIdentifier(const std::string & name)
 {
     std::smatch match;
@@ -156,7 +154,7 @@ MixEvalArgs::MixEvalArgs()
             fetchers::overrideRegistry(from.input, to.input, extraAttrs);
         }},
         .completer = {[&](AddCompletions & completions, size_t, std::string_view prefix) {
-            completeFlakeRef(aio(), completions, aio().blockOn(openStore()), prefix);
+            completeFlakeRef(completions, openStore(), prefix);
         }}
     });
 
@@ -189,35 +187,30 @@ Bindings * MixEvalArgs::getAutoArgs(Evaluator & state)
     return res.finish();
 }
 
-kj::Promise<Result<EvalPaths::PathResult<SourcePath, ThrownError>>>
-lookupFileArg(Evaluator & state, std::string_view fileArg)
-try {
+SourcePath lookupFileArg(Evaluator & state, std::string_view fileArg)
+{
     if (EvalSettings::isPseudoUrl(fileArg)) {
         auto const url = EvalSettings::resolvePseudoUrl(fileArg);
-        auto const downloaded = TRY_AWAIT(fetchers::downloadTarball(
+        auto const downloaded = fetchers::downloadTarball(
             state.store,
             url,
             /* name */ "source",
             /* locked */ false
-        ));
+        );
         StorePath const storePath = downloaded.tree.storePath;
-        co_return SourcePath(CanonPath(state.store->toRealPath(storePath)));
+        return CanonPath(state.store->toRealPath(storePath));
     } else if (fileArg.starts_with("flake:")) {
         experimentalFeatureSettings.require(Xp::Flakes);
         static constexpr size_t FLAKE_LEN = std::string_view("flake:").size();
         auto flakeRef = parseFlakeRef(std::string(fileArg.substr(FLAKE_LEN)), {}, true, false);
-        auto storePath = TRY_AWAIT(TRY_AWAIT(flakeRef.resolve(state.store)).fetchTree(state.store))
-                             .first.storePath;
-        co_return SourcePath(CanonPath(state.store->toRealPath(storePath)));
-    } else if (fileArg.size() > 2 && fileArg.at(0) == '<' && fileArg.at(fileArg.size() - 1) == '>')
-    {
+        auto storePath = flakeRef.resolve(state.store).fetchTree(state.store).first.storePath;
+        return CanonPath(state.store->toRealPath(storePath));
+    } else if (fileArg.size() > 2 && fileArg.at(0) == '<' && fileArg.at(fileArg.size() - 1) == '>') {
         Path p(fileArg.substr(1, fileArg.size() - 2));
-        co_return TRY_AWAIT(state.paths.findFile(p));
+        return state.paths.findFile(p);
     } else {
-        co_return SourcePath(CanonPath::fromCwd(fileArg));
+        return CanonPath::fromCwd(fileArg);
     }
-} catch (...) {
-    co_return result::current_exception();
 }
 
 }

lix/libcmd/common-eval-args.hh

@@ -1,7 +1,6 @@
 #pragma once
 ///@file
 
-#include "lix/libexpr/eval-error.hh"
 #include "lix/libexpr/eval.hh"
 #include "lix/libutil/args.hh"
 #include "lix/libmain/common-args.hh"
@@ -50,7 +49,6 @@ private:
  *
  * @exception nix::ThrownError for failed search path lookup. Probably others.
  */
-kj::Promise<Result<EvalPaths::PathResult<SourcePath, ThrownError>>>
-lookupFileArg(Evaluator & state, std::string_view fileArg);
+SourcePath lookupFileArg(Evaluator & state, std::string_view fileArg);
 
 }

lix/libcmd/installable-attr-path.cc

@@ -7,6 +7,8 @@
 #include "lix/libexpr/get-drvs.hh"
 #include "lix/libexpr/flake/flake.hh"
 
+#include <nlohmann/json.hpp>
+
 namespace nix {
 
 InstallableAttrPath::InstallableAttrPath(
@@ -76,7 +78,7 @@ DerivedPathsWithInfo InstallableAttrPath::toDerivedPaths(EvalState & state)
     for (auto & [drvPath, outputs] : byDrvPath)
         res.push_back({
             .path = DerivedPath::Built {
-                .drvPath = makeConstantStorePath(drvPath),
+                .drvPath = makeConstantStorePathRef(drvPath),
                 .outputs = outputs,
             },
             .info = make_ref<ExtraPathInfoValue>(ExtraPathInfoValue::Value {

lix/libcmd/installable-attr-path.hh

@@ -8,6 +8,8 @@
 #include "lix/libcmd/common-eval-args.hh"
 #include "lix/libexpr/eval.hh"
 
+#include <nlohmann/json.hpp>
+
 namespace nix {
 
 class InstallableAttrPath : public InstallableValue

lix/libcmd/installable-derived-path.cc

@@ -35,7 +35,7 @@ InstallableDerivedPath InstallableDerivedPath::parse(
             // Remove this prior to stabilizing the new CLI.
             if (storePath.isDerivation()) {
                 auto oldDerivedPath = DerivedPath::Built {
-                    .drvPath = makeConstantStorePath(storePath),
+                    .drvPath = makeConstantStorePathRef(storePath),
                     .outputs = OutputsSpec::All { },
                 };
                 warn(
@@ -48,7 +48,8 @@ InstallableDerivedPath InstallableDerivedPath::parse(
         },
         // If the user did use ^, we just do exactly what is written.
         [&](const ExtendedOutputsSpec::Explicit & outputSpec) -> DerivedPath {
-            auto drv = DerivedPathOpaque::parse(*store, prefix);
+            auto drv = make_ref<SingleDerivedPath>(SingleDerivedPath::parse(*store, prefix));
+            drvRequireExperiment(*drv);
             return DerivedPath::Built {
                 .drvPath = std::move(drv),
                 .outputs = outputSpec,

lix/libcmd/installable-flake.cc

@@ -1,11 +1,24 @@
+#include "lix/libstore/globals.hh"
 #include "lix/libcmd/installable-flake.hh"
+#include "lix/libcmd/installable-derived-path.hh"
 #include "lix/libstore/outputs-spec.hh"
 #include "lix/libcmd/command.hh"
 #include "lix/libexpr/attr-path.hh"
 #include "lix/libcmd/common-eval-args.hh"
+#include "lix/libstore/derivations.hh"
+#include "lix/libexpr/eval-inline.hh"
 #include "lix/libexpr/eval.hh"
+#include "lix/libexpr/get-drvs.hh"
+#include "lix/libstore/store-api.hh"
+#include "lix/libmain/shared.hh"
 #include "lix/libexpr/flake/flake.hh"
 #include "lix/libexpr/eval-cache.hh"
+#include "lix/libutil/url.hh"
+#include "lix/libfetchers/registry.hh"
+#include "lix/libstore/build-result.hh"
+
+#include <regex>
+#include <queue>
 
 #include <nlohmann/json.hpp>
 
@@ -98,7 +111,7 @@ DerivedPathsWithInfo InstallableFlake::toDerivedPaths(EvalState & state)
 
     return {{
         .path = DerivedPath::Built {
-            .drvPath = makeConstantStorePath(std::move(drvPath)),
+            .drvPath = makeConstantStorePathRef(std::move(drvPath)),
             .outputs = std::visit(overloaded {
                 [&](const ExtendedOutputsSpec::Default & d) -> OutputsSpec {
                     std::set<std::string> outputsToInstall;

lix/libcmd/installable-value.cc

@@ -1,7 +1,6 @@
 #include "lix/libcmd/installable-value.hh"
 #include "lix/libexpr/eval-cache.hh"
 #include "lix/libfetchers/fetch-to-store.hh"
-#include "lix/libutil/archive.hh"
 
 namespace nix {
 
@@ -37,10 +36,10 @@ InstallableValue & InstallableValue::require(Installable & installable)
 
 ref<InstallableValue> InstallableValue::require(ref<Installable> installable)
 {
-    auto castedInstallable = installable.try_cast<InstallableValue>();
+    auto castedInstallable = installable.dynamic_pointer_cast<InstallableValue>();
     if (!castedInstallable)
         throw nonValueInstallable(*installable);
-    return *castedInstallable;
+    return ref { castedInstallable };
 }
 
 std::optional<DerivedPathWithInfo> InstallableValue::trySinglePathToDerivedPaths(
@@ -48,10 +47,7 @@ std::optional<DerivedPathWithInfo> InstallableValue::trySinglePathToDerivedPaths
 )
 {
     if (v.type() == nPath) {
-        auto storePath = state.aio.blockOn(fetchToStoreRecursive(
-            *evaluator->store,
-            *prepareDump(state.ctx.paths.checkSourcePath(v.path()).canonical().abs())
-        ));
+        auto storePath = fetchToStore(*evaluator->store, state.ctx.paths.checkSourcePath(v.path()));
         return {{
             .path = DerivedPath::Opaque {
                 .path = std::move(storePath),

lix/libcmd/installables.cc

@@ -3,7 +3,6 @@
 #include "lix/libcmd/installable-derived-path.hh"
 #include "lix/libcmd/installable-attr-path.hh"
 #include "lix/libcmd/installable-flake.hh"
-#include "lix/libutil/async.hh"
 #include "lix/libutil/logging.hh"
 #include "lix/libstore/outputs-spec.hh"
 #include "lix/libcmd/command.hh"
@@ -20,6 +19,8 @@
 #include "lix/libstore/build-result.hh"
 
 
+#include <nlohmann/json.hpp>
+
 namespace nix {
 
 void completeFlakeInputPath(
@@ -85,11 +86,9 @@ MixFlakeOptions::MixFlakeOptions()
         }},
         .completer = {[&](AddCompletions & completions, size_t n, std::string_view prefix) {
             if (n == 0) {
-                completeFlakeInputPath(
-                    completions, *getEvaluator()->begin(aio()), getFlakeRefsForCompletion(), prefix
-                );
+                completeFlakeInputPath(completions, *getEvaluator()->begin(), getFlakeRefsForCompletion(), prefix);
             } else if (n == 1) {
-                completeFlakeRef(aio(), completions, getEvaluator()->store, prefix);
+                completeFlakeRef(completions, getEvaluator()->store, prefix);
             }
         }}
     });
@@ -122,7 +121,7 @@ MixFlakeOptions::MixFlakeOptions()
         .category = category,
         .labels = {"flake-url"},
         .handler = {[&](std::string flakeRef) {
-            auto evalState = getEvaluator()->begin(aio());
+            auto evalState = getEvaluator()->begin();
             auto flake = flake::lockFlake(
                 *evalState,
                 parseFlakeRef(flakeRef, absPath(".")),
@@ -138,7 +137,7 @@ MixFlakeOptions::MixFlakeOptions()
             }
         }},
         .completer = {[&](AddCompletions & completions, size_t, std::string_view prefix) {
-            completeFlakeRef(aio(), completions, getEvaluator()->store, prefix);
+            completeFlakeRef(completions, getEvaluator()->store, prefix);
         }}
     });
 }
@@ -183,8 +182,8 @@ MixReadOnlyOption::MixReadOnlyOption()
 Strings SourceExprCommand::getDefaultFlakeAttrPaths()
 {
     return {
-        "packages." + evalSettings.getCurrentSystem() + ".default",
-        "defaultPackage." + evalSettings.getCurrentSystem()
+        "packages." + settings.thisSystem.get() + ".default",
+        "defaultPackage." + settings.thisSystem.get()
     };
 }
 
@@ -193,17 +192,17 @@ Strings SourceExprCommand::getDefaultFlakeAttrPathPrefixes()
     return {
         // As a convenience, look for the attribute in
         // 'outputs.packages'.
-        "packages." + evalSettings.getCurrentSystem() + ".",
+        "packages." + settings.thisSystem.get() + ".",
         // As a temporary hack until Nixpkgs is properly converted
         // to provide a clean 'packages' set, look in 'legacyPackages'.
-        "legacyPackages." + evalSettings.getCurrentSystem() + "."
+        "legacyPackages." + settings.thisSystem.get() + "."
     };
 }
 
 Args::CompleterClosure SourceExprCommand::getCompleteInstallable()
 {
     return [this](AddCompletions & completions, size_t, std::string_view prefix) {
-        completeInstallable(*getEvaluator()->begin(aio()), completions, prefix);
+        completeInstallable(*getEvaluator()->begin(), completions, prefix);
     };
 }
 
@@ -215,9 +214,9 @@ void SourceExprCommand::completeInstallable(EvalState & state, AddCompletions &
 
             auto evaluator = getEvaluator();
 
-            Expr & e = evaluator->parseExprFromFile(state.ctx.paths.resolveExprPath(
-                state.aio.blockOn(lookupFileArg(*evaluator, *file)).unwrap()
-            ));
+            Expr & e = evaluator->parseExprFromFile(
+                state.ctx.paths.resolveExprPath(lookupFileArg(*evaluator, *file))
+            );
 
             Value root;
             state.eval(e, root);
@@ -239,7 +238,7 @@ void SourceExprCommand::completeInstallable(EvalState & state, AddCompletions &
             Value &v1(*v);
             state.forceValue(v1, pos);
             Value v2;
-            state.autoCallFunction(*autoArgs, v1, v2, pos);
+            state.autoCallFunction(*autoArgs, v1, v2);
 
             if (v2.type() == nAttrs) {
                 for (auto & i : *v2.attrs) {
@@ -281,7 +280,7 @@ void completeFlakeRefWithFragment(
     try {
         auto hash = prefix.find('#');
         if (hash == std::string::npos) {
-            completeFlakeRef(evalState.aio, completions, evaluator->store, prefix);
+            completeFlakeRef(completions, evaluator->store, prefix);
         } else {
             completions.setType(AddCompletions::Type::Attrs);
 
@@ -348,9 +347,7 @@ void completeFlakeRefWithFragment(
     }
 }
 
-void completeFlakeRef(
-    AsyncIoRoot & aio, AddCompletions & completions, ref<Store> store, std::string_view prefix
-)
+void completeFlakeRef(AddCompletions & completions, ref<Store> store, std::string_view prefix)
 {
     if (!experimentalFeatureSettings.isEnabled(Xp::Flakes))
         return;
@@ -361,7 +358,7 @@ void completeFlakeRef(
     Args::completeDir(completions, 0, prefix);
 
     /* Look for registry entries that match the prefix. */
-    for (auto & registry : aio.blockOn(fetchers::getRegistries(store))) {
+    for (auto & registry : fetchers::getRegistries(store)) {
         for (auto & entry : registry->entries) {
             auto from = entry.from.to_string();
             if (!prefix.starts_with("flake:") && from.starts_with("flake:")) {
@@ -384,18 +381,16 @@ DerivedPathWithInfo Installable::toDerivedPath(EvalState & state)
     return std::move(buildables[0]);
 }
 
-static kj::Promise<Result<StorePath>> getDeriver(
+static StorePath getDeriver(
     ref<Store> store,
     const Installable & i,
     const StorePath & drvPath)
-try {
-    auto derivers = TRY_AWAIT(store->queryValidDerivers(drvPath));
+{
+    auto derivers = store->queryValidDerivers(drvPath);
     if (derivers.empty())
         throw Error("'%s' does not have a known deriver", i.what());
     // FIXME: use all derivers?
-    co_return *derivers.begin();
-} catch (...) {
-    co_return result::current_exception();
+    return *derivers.begin();
 }
 
 ref<eval_cache::EvalCache> openEvalCache(
@@ -457,7 +452,7 @@ Installables SourceExprCommand::parseInstallables(
             state.eval(e, *vFile);
         }
         else if (file)
-            state.evalFile(state.aio.blockOn(lookupFileArg(*evaluator, *file)).unwrap(), *vFile);
+            state.evalFile(lookupFileArg(*evaluator, *file), *vFile);
         else {
             auto & e = evaluator->parseExprFromString(*expr, CanonPath::fromCwd());
             state.eval(e, *vFile);
@@ -524,6 +519,30 @@ ref<Installable> SourceExprCommand::parseInstallable(
     return installables.front();
 }
 
+static SingleBuiltPath getBuiltPath(ref<Store> evalStore, ref<Store> store, const SingleDerivedPath & b)
+{
+    return std::visit(
+        overloaded{
+            [&](const SingleDerivedPath::Opaque & bo) -> SingleBuiltPath {
+                return SingleBuiltPath::Opaque { bo.path };
+            },
+            [&](const SingleDerivedPath::Built & bfd) -> SingleBuiltPath {
+                auto drvPath = getBuiltPath(evalStore, store, *bfd.drvPath);
+                // Resolving this instead of `bfd` will yield the same result, but avoid duplicative work.
+                SingleDerivedPath::Built truncatedBfd {
+                    .drvPath = makeConstantStorePathRef(drvPath.outPath()),
+                    .output = bfd.output,
+                };
+                auto outputPath = resolveDerivedPath(*store, truncatedBfd, &*evalStore);
+                return SingleBuiltPath::Built {
+                    .drvPath = make_ref<SingleBuiltPath>(std::move(drvPath)),
+                    .output = { bfd.output, outputPath },
+                };
+            },
+        },
+        b.raw());
+}
+
 std::vector<BuiltPathWithResult> Installable::build(
     EvalState & state,
     ref<Store> evalStore,
@@ -602,17 +621,16 @@ std::vector<std::pair<ref<Installable>, BuiltPathWithResult>> Installable::build
 
     case Realise::Nothing:
     case Realise::Derivation:
-        state.aio.blockOn(printMissing(store, pathsToBuild, lvlError));
+        printMissing(store, pathsToBuild, lvlError);
 
         for (auto & path : pathsToBuild) {
             for (auto & aux : backmap[path]) {
                 std::visit(overloaded {
                     [&](const DerivedPath::Built & bfd) {
-                        auto outputs =
-                            state.aio.blockOn(resolveDerivedPath(*store, bfd, &*evalStore));
+                        auto outputs = resolveDerivedPath(*store, bfd, &*evalStore);
                         res.push_back({aux.installable, {
                             .path = BuiltPath::Built {
-                                .drvPath = bfd.drvPath,
+                                .drvPath = make_ref<SingleBuiltPath>(getBuiltPath(evalStore, store, *bfd.drvPath)),
                                 .outputs = outputs,
                              },
                             .info = aux.info}});
@@ -630,10 +648,9 @@ std::vector<std::pair<ref<Installable>, BuiltPathWithResult>> Installable::build
 
     case Realise::Outputs: {
         if (settings.printMissing)
-            state.aio.blockOn(printMissing(store, pathsToBuild, lvlInfo));
+            printMissing(store, pathsToBuild, lvlInfo);
 
-        auto buildResults =
-            state.aio.blockOn(store->buildPathsWithResults(pathsToBuild, bMode, evalStore));
+        auto buildResults = store->buildPathsWithResults(pathsToBuild, bMode, evalStore);
         throwBuildErrors(buildResults, *store);
         for (auto & buildResult : buildResults) {
             for (auto & aux : backmap[buildResult.path]) {
@@ -644,7 +661,7 @@ std::vector<std::pair<ref<Installable>, BuiltPathWithResult>> Installable::build
                             outputs.emplace(outputName, realisation.outPath);
                         res.push_back({aux.installable, {
                             .path = BuiltPath::Built {
-                                .drvPath = bfd.drvPath,
+                                .drvPath = make_ref<SingleBuiltPath>(getBuiltPath(evalStore, store, *bfd.drvPath)),
                                 .outputs = outputs,
                             },
                             .info = aux.info,
@@ -755,11 +772,11 @@ StorePathSet Installable::toDerivations(
                         bo.path.isDerivation()
                             ? bo.path
                         : useDeriver
-                            ? state.aio.blockOn(getDeriver(store, *i, bo.path))
+                            ? getDeriver(store, *i, bo.path)
                         : throw Error("argument '%s' did not evaluate to a derivation", i->what()));
                 },
                 [&](const DerivedPath::Built & bfd) {
-                    drvPaths.insert(bfd.drvPath.path);
+                    drvPaths.insert(resolveDerivedPath(*store, *bfd.drvPath));
                 },
             }, b.path.raw());
 
@@ -825,7 +842,7 @@ std::vector<FlakeRef> InstallableCommand::getFlakeRefsForCompletion()
 
 void InstallablesCommand::run(ref<Store> store, std::vector<std::string> && rawInstallables)
 {
-    auto installables = parseInstallables(*getEvaluator()->begin(aio()), store, rawInstallables);
+    auto installables = parseInstallables(*getEvaluator()->begin(), store, rawInstallables);
     run(store, std::move(installables));
 }
 
@@ -842,7 +859,7 @@ InstallableCommand::InstallableCommand()
 
 void InstallableCommand::run(ref<Store> store)
 {
-    auto installable = parseInstallable(*getEvaluator()->begin(aio()), store, _installable);
+    auto installable = parseInstallable(*getEvaluator()->begin(), store, _installable);
     run(store, std::move(installable));
 }
 

lix/libcmd/installables.hh

@@ -3,6 +3,7 @@
 
 #include "lix/libexpr/eval.hh"
 #include "lix/libstore/path.hh"
+#include "lix/libstore/outputs-spec.hh"
 #include "lix/libstore/derived-path.hh"
 #include "lix/libcmd/built-path.hh"
 #include "lix/libstore/store-api.hh"

lix/libcmd/legacy.cc

@@ -2,6 +2,6 @@
 
 namespace nix {
 
-LegacyCommandRegistry::LegacyCommandMap * LegacyCommandRegistry::commands = 0;
+LegacyCommands::Commands * LegacyCommands::commands = 0;
 
 }

lix/libcmd/legacy.hh

@@ -1,7 +1,6 @@
 #pragma once
 ///@file
 
-#include "lix/libutil/async.hh"
 #include <functional>
 #include <list>
 #include <map>
@@ -9,16 +8,16 @@
 
 namespace nix {
 
-typedef std::function<void(AsyncIoRoot &, std::string, std::list<std::string>)> MainFunction;
+typedef std::function<void(std::string, std::list<std::string>)> MainFunction;
 
-struct LegacyCommandRegistry
+struct LegacyCommands
 {
-    using LegacyCommandMap = std::map<std::string, MainFunction>;
-    static LegacyCommandMap * commands;
+    typedef std::map<std::string, MainFunction> Commands;
+    static Commands * commands;
 
     static void add(const std::string & name, MainFunction fun)
     {
-        if (!commands) commands = new LegacyCommandMap;
+        if (!commands) commands = new Commands;
         (*commands)[name] = fun;
     }
 };

lix/libcmd/markdown.cc

@@ -8,7 +8,7 @@
 
 namespace nix {
 
-std::string renderMarkdownToTerminal(std::string_view markdown, StandardOutputStream fileno)
+std::string renderMarkdownToTerminal(std::string_view markdown)
 {
     int windowWidth = getWindowSize().second;
 
@@ -21,9 +21,6 @@ std::string renderMarkdownToTerminal(std::string_view markdown, StandardOutputSt
         .feat = LOWDOWN_COMMONMARK | LOWDOWN_FENCED | LOWDOWN_DEFLIST | LOWDOWN_TABLES,
         .oflags = LOWDOWN_TERM_NOLINK,
     };
-    if (!shouldANSI(fileno)) {
-        opts.oflags |= LOWDOWN_TERM_NOANSI;
-    }
 
     auto doc = lowdown_doc_new(&opts);
     if (!doc)
@@ -50,7 +47,7 @@ std::string renderMarkdownToTerminal(std::string_view markdown, StandardOutputSt
     if (!rndr_res)
         throw Error("allocation error while rendering Markdown");
 
-    return std::string(buf->data, buf->size);
+    return filterANSIEscapes(std::string(buf->data, buf->size), !shouldANSI());
 }
 
 }

lix/libcmd/markdown.hh

@@ -1,11 +1,10 @@
 #pragma once
 ///@file
 
-#include "lix/libutil/terminal.hh"
 #include "lix/libutil/types.hh"
 
 namespace nix {
 
-std::string renderMarkdownToTerminal(std::string_view markdown, StandardOutputStream fileno = StandardOutputStream::Stdout);
+std::string renderMarkdownToTerminal(std::string_view markdown);
 
 }

lix/libcmd/meson.build

@@ -46,12 +46,12 @@ libcmd = library(
     liblixexpr,
     liblixfetchers,
     liblixmain,
+    boehm,
     ncurses,
     editline,
     lowdown,
     nlohmann_json,
     liblix_doc,
-    kj,
   ],
   # '../..' for self references like "lix/libcmd/*.hh"
   include_directories : [ '../..' ],
@@ -74,7 +74,6 @@ liblixcmd = declare_dependency(
   include_directories : include_directories('../..'),
   link_with : libcmd,
 )
-meson.override_dependency('lix-cmd', liblixcmd)
 
 # FIXME: not using the pkg-config module because it creates way too many deps
 # while meson migration is in progress, and we want to not include boost here

lix/libcmd/repl.cc

@@ -12,7 +12,10 @@
 
 #include "lix/libutil/ansicolor.hh"
 #include "lix/libmain/shared.hh"
+#include "lix/libutil/escape-string.hh"
 #include "lix/libexpr/eval.hh"
+#include "lix/libexpr/eval-cache.hh"
+#include "lix/libexpr/eval-inline.hh"
 #include "lix/libexpr/eval-settings.hh"
 #include "lix/libexpr/attr-path.hh"
 #include "lix/libutil/signals.hh"
@@ -31,7 +34,6 @@
 #include "lix/libutil/signals.hh"
 #include "lix/libexpr/print.hh"
 #include "lix/libexpr/gc-small-vector.hh"
-#include "lix/libutil/types.hh"
 #include "lix/libutil/users.hh"
 
 #if HAVE_BOEHMGC
@@ -153,15 +155,9 @@ struct NixRepl
     void loadFlake(const std::string & flakeRef);
     void loadFiles();
     void reloadFiles();
-
-    template<typename T, typename NameFn, typename ValueFn>
-    void addToScope(T && things, NameFn nameFn, ValueFn valueFn);
-
     void addAttrsToScope(Value & attrs);
-    void addValMapToScope(const ValMap & attrs);
     void addVarToScope(const Symbol name, Value & v);
     Expr & parseString(std::string s);
-    std::variant<std::unique_ptr<Expr>, ExprReplBindings> parseReplString(std::string s);
     void evalString(std::string s, Value & v);
     void loadDebugTraceEnv(const DebugTrace & dt);
 
@@ -248,13 +244,13 @@ NixRepl::NixRepl(const SearchPath & searchPath, nix::ref<Store> store, EvalState
 void runNix(Path program, const Strings & args)
 {
     auto subprocessEnv = getEnv();
-    subprocessEnv["NIX_CONFIG"] = globalConfig.toKeyValue(true);
+    subprocessEnv["NIX_CONFIG"] = globalConfig.toKeyValue();
 
     runProgram2(RunOptions {
         .program = settings.nixBinDir+ "/" + program,
         .args = args,
         .environment = subprocessEnv,
-    }).wait();
+    }).waitAndCheck();
 
     return;
 }
@@ -475,6 +471,23 @@ StringSet NixRepl::completePrefix(const std::string &prefix)
     return completions;
 }
 
+
+// FIXME: DRY and match or use the parser
+static bool isVarName(std::string_view s)
+{
+    if (s.size() == 0) return false;
+    char c = s[0];
+    if ((c >= '0' && c <= '9') || c == '-' || c == '\'') return false;
+    for (auto & i : s)
+        if (!((i >= 'a' && i <= 'z') ||
+              (i >= 'A' && i <= 'Z') ||
+              (i >= '0' && i <= '9') ||
+              i == '_' || i == '-' || i == '\''))
+            return false;
+    return true;
+}
+
+
 StorePath NixRepl::getDerivationPath(Value & v) {
     auto drvInfo = getDerivation(state, v, false);
     if (!drvInfo)
@@ -482,7 +495,7 @@ StorePath NixRepl::getDerivationPath(Value & v) {
     auto drvPath = drvInfo->queryDrvPath(state);
     if (!drvPath)
         throw Error("expression did not evaluate to a valid derivation (no 'drvPath' attribute)");
-    if (!state.aio.blockOn(evaluator.store->isValidPath(*drvPath)))
+    if (!evaluator.store->isValidPath(*drvPath))
         throw Error("expression evaluated to invalid derivation '%s'", evaluator.store->printStorePath(*drvPath));
     return *drvPath;
 }
@@ -496,7 +509,8 @@ void NixRepl::loadDebugTraceEnv(const DebugTrace & dt)
         auto vm = mapStaticEnvBindings(evaluator.symbols, *se.get(), dt.env);
 
         // add staticenv vars.
-        addValMapToScope(*vm);
+        for (auto & [name, value] : *(vm.get()))
+            addVarToScope(evaluator.symbols.create(name), *value);
     }
 }
 
@@ -516,8 +530,6 @@ ProcessLineResult NixRepl::processLine(std::string line)
         arg = line;
     }
 
-    bool inDebugger = evaluator.debug && evaluator.debug->inDebugger;
-
     if (command == ":?" || command == ":help") {
         // FIXME: convert to Markdown, include in the 'nix repl' manpage.
         std::cout
@@ -530,7 +542,6 @@ ProcessLineResult NixRepl::processLine(std::string line)
              << "  :bl <expr>                   Build a derivation, creating GC roots in the\n"
              << "                               working directory\n"
              << "  :e, :edit <expr>             Open package or function in $EDITOR\n"
-             << "  :env                         Show env stack\n"
              << "  :i <expr>                    Build derivation, then install result into\n"
              << "                               current profile\n"
              << "  :l, :load <path>             Load Nix expression and add it to scope\n"
@@ -549,10 +560,11 @@ ProcessLineResult NixRepl::processLine(std::string line)
              << "                               errors\n"
              << "  :?, :help                    Brings up this help menu\n"
              ;
-        if (inDebugger) {
+        if (evaluator.debug && evaluator.debug->inDebugger) {
              std::cout
              << "\n"
              << "        Debug mode commands\n"
+             << "  :env             Show env stack\n"
              << "  :bt, :backtrace  Show trace stack\n"
              << "  :st              Show current trace\n"
              << "  :st <idx>        Change to another trace in the stack\n"
@@ -563,9 +575,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
 
     }
 
-    else if (command == ":bt" || command == ":backtrace") {
-        if (!inDebugger)
-            throw Error("backtrace command is only available in debug mode (see %s)", "--debugger");
+    else if (evaluator.debug && evaluator.debug->inDebugger && (command == ":bt" || command == ":backtrace")) {
         auto traces = evaluator.debug->traces();
         for (const auto & [idx, i] : enumerate(traces)) {
             std::cout << "\n" << ANSI_BLUE << idx << ANSI_NORMAL << ": ";
@@ -573,23 +583,17 @@ ProcessLineResult NixRepl::processLine(std::string line)
         }
     }
 
-    else if (command == ":env") {
-        if (inDebugger) {
-            auto traces = evaluator.debug->traces();
-            for (const auto & [idx, i] : enumerate(traces)) {
-                if (idx == debugTraceIndex) {
-                    printEnvBindings(state, i->expr, i->env);
-                    break;
-                }
+    else if (evaluator.debug && evaluator.debug->inDebugger && (command == ":env")) {
+        auto traces = evaluator.debug->traces();
+        for (const auto & [idx, i] : enumerate(traces)) {
+            if (idx == debugTraceIndex) {
+                printEnvBindings(state, i->expr, i->env);
+                break;
             }
-        } else {
-            printEnvBindings(state.ctx.symbols, *staticEnv, *env, 0);
         }
     }
 
-    else if (command == ":st") {
-        if (!inDebugger)
-            throw Error("trace command is only available in debug mode (see %s)", "--debugger");
+    else if (evaluator.debug && evaluator.debug->inDebugger && (command == ":st")) {
         try {
             // change the DebugTrace index.
             debugTraceIndex = stoi(arg);
@@ -608,17 +612,13 @@ ProcessLineResult NixRepl::processLine(std::string line)
         }
     }
 
-    else if (command == ":s" || command == ":step") {
-        if (!inDebugger)
-            throw Error("step command is only available in debug mode (see %s)", "--debugger");
+    else if (evaluator.debug && evaluator.debug->inDebugger && (command == ":s" || command == ":step")) {
         // set flag to stop at next DebugTrace; exit repl.
         evaluator.debug->stop = true;
         return ProcessLineResult::Continue;
     }
 
-    else if (command == ":c" || command == ":continue") {
-        if (!inDebugger)
-            throw Error("continue command is only available in debug mode (see %s)", "--debugger");
+    else if (evaluator.debug && evaluator.debug->inDebugger && (command == ":c" || command == ":continue")) {
         // set flag to run to next breakpoint or end of program; exit repl.
         evaluator.debug->stop = false;
         return ProcessLineResult::Continue;
@@ -672,7 +672,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
 
         // runProgram redirects stdout to a StringSink,
         // using runProgram2 to allow editors to display their UI
-        runProgram2(RunOptions { .program = editor, .searchPath = true, .args = args }).wait();
+        runProgram2(RunOptions { .program = editor, .searchPath = true, .args = args }).waitAndCheck();
 
         // Reload right after exiting the editor if path is not in store
         // Store is immutable, so there could be no changes, so there's no need to reload
@@ -699,8 +699,6 @@ ProcessLineResult NixRepl::processLine(std::string line)
     }
 
     else if (command == ":log") {
-        if (arg.empty())
-            throw Error("cannot use ':log' without a specifying a derivation");
         StorePath drvPath = ([&] {
             auto maybeDrvPath = evaluator.store->maybeParseStorePath(arg);
             if (maybeDrvPath && maybeDrvPath->isDerivation()) {
@@ -717,7 +715,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
         Finally roModeReset([&]() {
             settings.readOnlyMode = false;
         });
-        auto subs = state.aio.blockOn(getDefaultSubstituters());
+        auto subs = getDefaultSubstituters();
 
         subs.push_front(evaluator.store);
 
@@ -731,7 +729,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
             }
             auto & logSub = *logSubP;
 
-            auto log = state.aio.blockOn(logSub.getBuildLog(drvPath));
+            auto log = logSub.getBuildLog(drvPath);
             if (log) {
                 printInfo("got build log for '%s' from '%s'", drvPathRaw, logSub.getUri());
                 logger->writeToStdout(*log);
@@ -758,21 +756,19 @@ ProcessLineResult NixRepl::processLine(std::string line)
                 logger->pause();
             });
 
-            state.aio.blockOn(evaluator.store->buildPaths({
+            evaluator.store->buildPaths({
                 DerivedPath::Built {
-                    .drvPath = makeConstantStorePath(drvPath),
+                    .drvPath = makeConstantStorePathRef(drvPath),
                     .outputs = OutputsSpec::All { },
                 },
-            }));
-            auto drv = state.aio.blockOn(evaluator.store->readDerivation(drvPath));
+            });
+            auto drv = evaluator.store->readDerivation(drvPath);
             logger->cout("\nThis derivation produced the following outputs:");
-            for (auto & [outputName, outputPath] :
-                 state.aio.blockOn(evaluator.store->queryDerivationOutputMap(drvPath)))
-            {
-                auto localStore = evaluator.store.try_cast_shared<LocalFSStore>();
+            for (auto & [outputName, outputPath] : evaluator.store->queryDerivationOutputMap(drvPath)) {
+                auto localStore = evaluator.store.dynamic_pointer_cast<LocalFSStore>();
                 if (localStore && command == ":bl") {
                     std::string symlink = "repl-result-" + outputName;
-                    state.aio.blockOn(localStore->addPermRoot(outputPath, absPath(symlink)));
+                    localStore->addPermRoot(outputPath, absPath(symlink));
                     logger->cout("  ./%s -> %s", symlink, evaluator.store->printStorePath(outputPath));
                 } else {
                     logger->cout("  %s -> %s", outputName, evaluator.store->printStorePath(outputPath));
@@ -858,26 +854,23 @@ ProcessLineResult NixRepl::processLine(std::string line)
         throw Error("unknown command '%1%'", command);
 
     else {
-        /* A line is either a regular expression or a `var = expr` assignment */
-        std::variant<std::unique_ptr<Expr>, ExprReplBindings> result = parseReplString(line);
-        std::visit(overloaded {
-            [&](ExprReplBindings & b) {
-                for (auto & [name, e] : b.symbols) {
-                    Value * v = state.ctx.mem.allocValue();
-                    e->eval(state, *env, *v);
-                    (void) e.release(); // NOLINT(bugprone-unused-return-value): leak because of thunk references
-                    addVarToScope(name, *v);
-                }
-            },
-            [&](std::unique_ptr<Expr> & e) {
-                Value v;
-                e->eval(state, *env, v);
-                (void) e.release(); // NOLINT(bugprone-unused-return-value): leak because of thunk references
-                state.forceValue(v, noPos);
-                printValue(std::cout, v, 1);
-                std::cout << std::endl;
-            }
-        }, result);
+        size_t p = line.find('=');
+        std::string name;
+        if (p != std::string::npos &&
+            p < line.size() &&
+            line[p + 1] != '=' &&
+            isVarName(name = removeWhitespace(line.substr(0, p))))
+        {
+            Expr & e = parseString(line.substr(p + 1));
+            Value & v(*evaluator.mem.allocValue());
+            v.mkThunk(env, e);
+            addVarToScope(evaluator.symbols.create(name), v);
+        } else {
+            Value v;
+            evalString(line, v);
+            printValue(std::cout, v, 1);
+            std::cout << std::endl;
+        }
     }
 
     return ProcessLineResult::PromptAgain;
@@ -888,8 +881,8 @@ void NixRepl::loadFile(const Path & path)
     loadedFiles.remove(path);
     loadedFiles.push_back(path);
     Value v, v2;
-    state.evalFile(state.aio.blockOn(lookupFileArg(evaluator, path)).unwrap(always_progresses), v);
-    state.autoCallFunction(*autoArgs, v, v2, noPos);
+    state.evalFile(lookupFileArg(evaluator, path), v);
+    state.autoCallFunction(*autoArgs, v, v2);
     addAttrsToScope(v2);
 }
 
@@ -966,7 +959,13 @@ void NixRepl::loadReplOverlays()
 
     Value &newAttrs(*evaluator.mem.allocValue());
     SmallValueVector<3> args = {replInitInfo(), bindingsToAttrs(), replOverlays()};
-    state.callFunction(*replInitFilesFunction, args.size(), args.data(), newAttrs, noPos);
+    state.callFunction(
+        *replInitFilesFunction,
+        args.size(),
+        args.data(),
+        newAttrs,
+        replInitFilesFunction->determinePos(noPos)
+    );
 
     // n.b. this does in fact load the stuff into the environment twice (once
     // from the superset of the environment returned by repl-overlays and once
@@ -1012,21 +1011,22 @@ Value * NixRepl::replOverlays()
 
         if (!replInit->isLambda()) {
             evaluator.errors.make<TypeError>(
-                "Expected `repl-overlays` entry %s to be a lambda but found %s: %s",
-                path,
+                "Expected `repl-overlays` to be a lambda but found %1%: %2%",
                 showType(*replInit),
                 ValuePrinter(state, *replInit, errorPrintOptions)
             )
+            .atPos(replInit->determinePos(noPos))
             .debugThrow();
         }
 
-        if (auto attrs = dynamic_cast<AttrsPattern *>(replInit->lambda.fun->pattern.get()); attrs && !attrs->ellipsis) {
+        if (replInit->lambda.fun->hasFormals()
+            && !replInit->lambda.fun->formals->ellipsis) {
             evaluator.errors.make<TypeError>(
                 "Expected first argument of %1% to have %2% to allow future versions of Lix to add additional attributes to the argument",
                 "repl-overlays",
                 "..."
             )
-                .atPos(replInit->lambda.fun->pos)
+                .atPos(replInit->determinePos(noPos))
                 .debugThrow();
         }
 
@@ -1052,57 +1052,31 @@ Value * NixRepl::replInitInfo()
 }
 
 
-template<typename T, typename NameFn, typename ValueFn>
-void NixRepl::addToScope(T && things, NameFn nameFn, ValueFn valueFn)
-{
-    size_t added = 0;
-
-    staticEnv->vars.unsafe_insert_bulk([&] (auto & map) {
-        auto oldSize = map.size();
-        for (auto && thing : things) {
-            if (displ + 1 >= envSize)
-                throw Error("environment full; cannot add more variables");
-
-            const auto name = nameFn(thing);
-            map.emplace_back(name, displ);
-            env->values[displ++] = valueFn(thing);
-            varNames.emplace(evaluator.symbols[name]);
-            added++;
-        }
-        // safety: we sort the range that we inserted so that we don't have to push that
-        // invariant up to the caller
-        std::sort(map.begin() + oldSize, map.end());
-    });
-
-    if (added > 0) {
-        notice("Added %1% variables.", added);
-    }
-}
-
 void NixRepl::addAttrsToScope(Value & attrs)
 {
-    state.forceAttrs(attrs, noPos, "while evaluating an attribute set to be merged in the global scope");
-    addToScope(*attrs.attrs, [](Attr & a) { return a.name; }, [](Attr & a) { return a.value; });
+    state.forceAttrs(attrs, attrs.determinePos(noPos), "while evaluating an attribute set to be merged in the global scope");
+    if (displ + attrs.attrs->size() >= envSize)
+        throw Error("environment full; cannot add more variables");
+
+    for (auto & i : *attrs.attrs) {
+        staticEnv->vars.emplace_back(i.name, displ);
+        env->values[displ++] = i.value;
+        varNames.emplace(evaluator.symbols[i.name]);
+    }
+    staticEnv->sort();
+    staticEnv->deduplicate();
+    notice("Added %1% variables.", attrs.attrs->size());
 }
 
-void NixRepl::addValMapToScope(const ValMap & attrs)
-{
-    addToScope(
-        attrs,
-        [&](auto & val) { return evaluator.symbols.create(val.first); },
-        [&](auto & val) { return val.second; }
-    );
-}
 
 void NixRepl::addVarToScope(const Symbol name, Value & v)
 {
     if (displ >= envSize)
         throw Error("environment full; cannot add more variables");
-    if (staticEnv->vars.insert_or_assign(name, displ).second) {
-        notice("Updated %s.", evaluator.symbols[name]);
-    } else {
-        notice("Added %s.", evaluator.symbols[name]);
-    }
+    if (auto oldVar = staticEnv->find(name); oldVar != staticEnv->vars.end())
+        staticEnv->vars.erase(oldVar);
+    staticEnv->vars.emplace_back(name, displ);
+    staticEnv->sort();
     env->values[displ++] = &v;
     varNames.emplace(evaluator.symbols[name]);
 }
@@ -1122,12 +1096,7 @@ Value * NixRepl::bindingsToAttrs()
 
 Expr & NixRepl::parseString(std::string s)
 {
-    return evaluator.parseExprFromString(std::move(s), CanonPath::fromCwd(), staticEnv, featureSettings);
-}
-
-std::variant<std::unique_ptr<Expr>, ExprReplBindings> NixRepl::parseReplString(std::string s)
-{
-    return evaluator.parseReplInput(std::move(s), CanonPath::fromCwd(), staticEnv, featureSettings);
+    return evaluator.parseExprFromString(std::move(s), CanonPath::fromCwd(), staticEnv);
 }
 
 
@@ -1135,7 +1104,7 @@ void NixRepl::evalString(std::string s, Value & v)
 {
     Expr & e = parseString(s);
     e.eval(state, *env, v);
-    state.forceValue(v, noPos);
+    state.forceValue(v, v.determinePos(noPos));
 }
 
 Value * NixRepl::evalFile(SourcePath & path)
@@ -1143,7 +1112,7 @@ Value * NixRepl::evalFile(SourcePath & path)
     auto & expr = evaluator.parseExprFromFile(evaluator.paths.checkSourcePath(path), staticEnv);
     Value * result(evaluator.mem.allocValue());
     expr.eval(state, *env, *result);
-    state.forceValue(*result, noPos);
+    state.forceValue(*result, result->determinePos(noPos));
     return result;
 }
 
@@ -1160,19 +1129,16 @@ ReplExitStatus AbstractNixRepl::run(
 
     repl.autoArgs = autoArgs;
     repl.initEnv();
-    repl.addValMapToScope(extraEnv);
+    for (auto & [name, value] : extraEnv) {
+        repl.addVarToScope(repl.evaluator.symbols.create(name), *value);
+    }
     return repl.mainLoop();
 }
 
 ReplExitStatus AbstractNixRepl::runSimple(EvalState & evalState, const ValMap & extraEnv)
 {
     return run(
-        {},
-        evalState.aio.blockOn(openStore()),
-        evalState,
-        [] { return AnnotatedValues{}; },
-        extraEnv,
-        nullptr
+        {}, openStore(), evalState, [] {  return AnnotatedValues{}; }, extraEnv, nullptr
     );
 }
 

lix/libcmd/repl.hh

@@ -2,11 +2,10 @@
 ///@file
 
 #include "lix/libexpr/eval.hh"
-#include "lix/libutil/types.hh"
 
 namespace nix {
 
-struct AbstractNixRepl : NeverAsync
+struct AbstractNixRepl
 {
     typedef std::vector<std::pair<Value*,std::string>> AnnotatedValues;
 

lix/libexpr/attr-path.cc

@@ -1,5 +1,5 @@
 #include "lix/libexpr/attr-path.hh"
-#include "lix/libutil/strings.hh"
+#include "lix/libexpr/eval-inline.hh"
 #include "print-options.hh"
 #include <algorithm>
 #include <sstream>
@@ -85,7 +85,7 @@ std::pair<Value *, PosIdx> findAlongAttrPath(EvalState & state, const std::strin
 
         /* Evaluate the expression. */
         Value * vNew = state.ctx.mem.allocValue();
-        state.autoCallFunction(autoArgs, *v, *vNew, pos);
+        state.autoCallFunction(autoArgs, *v, *vNew);
         v = vNew;
         state.forceValue(*v, noPos);
 
@@ -184,14 +184,15 @@ std::pair<SourcePath, uint32_t> findPackageFilename(EvalState & state, Value & v
         throw ParseError("cannot parse 'meta.position' attribute '%s'", fn);
     };
 
-    auto colon = fn.rfind(':');
-    if (colon == std::string::npos) fail();
-    // parsing as int32 instead of the uint32 we return for historical reasons.
-    // previously this was a stoi(), and we don't know what editors would do if
-    // we gave them line numbers that wouldn't fit into the int32 number space.
-    auto lineno = string2Int<int32_t>(std::string(fn, colon + 1, std::string::npos));
-    if (!lineno) fail();
-    return {CanonPath(fn.substr(0, colon)), *lineno};
+    try {
+        auto colon = fn.rfind(':');
+        if (colon == std::string::npos) fail();
+        auto lineno = std::stoi(std::string(fn, colon + 1, std::string::npos));
+        return {CanonPath(fn.substr(0, colon)), lineno};
+    } catch (std::invalid_argument & e) {
+        fail();
+        abort();
+    }
 }
 
 

lix/libexpr/attr-path.hh

@@ -4,6 +4,7 @@
 #include "lix/libexpr/eval.hh"
 
 #include <string>
+#include <map>
 
 namespace nix {
 

lix/libexpr/attr-set.hh

@@ -5,6 +5,7 @@
 #include "lix/libexpr/symbol-table.hh"
 
 #include <algorithm>
+#include <optional>
 
 namespace nix {
 

lix/libexpr/builtins/fetchGit.md

@@ -48,69 +48,6 @@ attribute with the following attributes (all except `url` optional):
   With this argument being true, it's possible to load a `rev` from *any* `ref`
   (by default only `rev`s from the specified `ref` are supported).
 
-- `narHash`
-
-  If given, the source is first looked-up in the Nix store and the [substituters](@docroot@/command-ref/conf-file.md#conf-substituters), and only fetched if not available.
-
-The return value is an attrset containing the following keys:
-
-- `lastModified` (`integer`)
-
-  Unix timestamp of the last update.
-  This corresponds to the timestamp of the "committer" timestamp embedded in the fetched commit.
-
-- `lastModifiedDate` (`string`)
-
-  Textual representation of the `lastModified` timestamp in UTC (the timezone embedded in the git commit is discarded).
-
-- `outPath` (`string`)
-
-  Resulting store path of the fetch process.
-
-- `narHash` (`string`)
-
-  SRI representation of the hash of the `outPath`.
-
-- `rev` (`string`)
-
-  The full-length revision fetched from the remote.
-  For further information see the `rev` input parameter.
-  This will usually be the output of `git rev-parse <rev>` (or `ref` when no `rev` is provided as an input parameter).
-
-- `revCount` (`integer`)
-
-  Number of revisions in the history of the revision fetched.
-  For a repository with a single commit (the root) this number equals 1.
-  Fetches of shallow repositories report a value of 0.
-
-- `shortRev` (`string`)
-
-  A short representation of the `rev`.
-  This string is a *truncated* version of the `rev`.
-  It is of fixed length and therefore not guaranteed to be unique (unlike the output of `git rev-parse --short`).
-  Future versions of Lix may change the length of this string only as part of a breaking change.
-  For maximum reproducibility and interoperability it is recommended to not rely on this value and to truncate the returned `rev` to an appropriate value instead.
-
-- `submodules` (`boolean`)
-
-  Indicates whether submodules have been fetched.
-  If this value is set to `true`, any submodules are already checked out in the resulting `outPath`.
-
-A full example of the output:
-
-```nix
-{
-  lastModified = 1746827286;
-  lastModifiedDate = "20250509214806";
-  narHash = "sha256-qCRBy8Bbh5XhPalPkhonxNgfsbw3lP0UIXBLSrhxAvI=";
-  outPath = "/nix/store/2qdnzhzccspwm70mni7jkvrfkpwcb3jn-source";
-  rev = "dcb0a97000d50b2868ed4f8d9fd465c5a5b8eb3a";
-  revCount = 17845;
-  shortRev = "dcb0a97";
-  submodules = false;
-}
-```
-
 Here are some examples of how to use `fetchGit`.
 
   - To fetch a private repository over SSH:
@@ -137,7 +74,7 @@ Here are some examples of how to use `fetchGit`.
     name in the `ref` attribute.
 
     However, if the revision you're looking for is in a future
-    branch for the non-default branch you will need to specify
+    branch for the non-default branch you will need to specify the
     the `ref` attribute as well.
 
     ```nix

lix/libexpr/builtins/fetchTarball.md

@@ -33,20 +33,10 @@ the attribute `url` and the attribute `sha256`, e.g.
 ```nix
 with import (fetchTarball {
   url = "https://github.com/NixOS/nixpkgs/archive/nixos-14.12.tar.gz";
-  sha256 = "sha256-QsrS6BEjO8ccwlmL1b7/5iPaemuM/Ibj9WWu7bKe98o=";
+  sha256 = "1jppksrfvbk5ypiqdz4cddxdl8z6zyzdb2srq8fcffr327ld5jj2";
 }) {};
 
 stdenv.mkDerivation { … }
 ```
 
-The `sha256` attribute accepts Nix-style base32 sha256 hashes (e.g.
-`1jppksrfvbk5ypiqdz4cddxdl8z6zyzdb2srq8fcffr327ld5jj2`), hashes
-in SRI format (as shown above), and some other less common hash
-algorithms and formats.
-
-<!--
-  TODO: Document all the accepted hash algorithms and formats
-  somewhere in the manual and link to it from here.
--->
-
 Not available in [restricted evaluation mode](@docroot@/command-ref/conf-file.md#conf-restrict-eval).