release: 2.90.0 "Vanilla Ice Cream"

Release produced with releng/create_release.xsh Change-Id: Ice53891cdeafff04bd6537be66e8cd6b7dd9678c
doc/release-notes: add date for major release
2024-07-10 08:40:42 -07:00 · 2024-07-10 15:35:00 +00:00 · 2024-07-10 15:32:19 +02:00 · 2024-06-16 19:06:45 -07:00
1841 changed files with 45242 additions and 74394 deletions
@@ -16,25 +16,3 @@ Checks:
  - -bugprone-unchecked-optional-access
    # many warnings, seems like a questionable lint
  - -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
-  - cppcoreguidelines-avoid-capturing-lambda-coroutines
-    # crimes must be appropriately declared as crimes
-  - cppcoreguidelines-pro-type-cstyle-cast
-  - lix-*
-    # This can not yet be applied to Lix itself since we need to do source
-    # reorganization so that lix/ include paths work.
-  - -lix-fixincludes
-    # This lint is included as an example, but the lib function it replaces is
-    # already gone.
-  - -lix-hasprefixsuffix
-
-
-CheckOptions:
-  bugprone-reserved-identifier.AllowedIdentifiers: '__asan_default_options'
-  bugprone-unused-return-value.AllowCastToVoid: true
@@ -29,11 +29,3 @@ trim_trailing_whitespace = false
 indent_style = space
 indent_size = 2
 max_line_length = 0
-
-[meson.build]
-indent_style = space
-indent_size = 2
-
-[*.json]
-indent_style = space
-indent_size = 4
@@ -1,5 +1,9 @@
 # shellcheck shell=bash
 source_env_if_exists .envrc.local
-# Use native-clangStdenvPackages to get clangd by default.
-use flake ".#${LIX_SHELL_VARIANT:-native-clangStdenvPackages}" "${LIX_SHELL_EXTRA_ARGS[@]}"
+# TODO: `use flake .#native-clangStdenvPackages` on macOS?
+use flake ".#${LIX_SHELL_VARIANT:-default}" "${LIX_SHELL_EXTRA_ARGS[@]}"
+export MAKEFLAGS="$MAKEFLAGS -e"
+if [[ -n "$NIX_BUILD_CORES" ]]; then
+    export MAKEFLAGS="$MAKEFLAGS -j $NIX_BUILD_CORES"
+fi
 export GTEST_BRIEF=1
@@ -2,7 +2,7 @@
 name: Missing or incorrect documentation
 about: Help us improve the reference manual
 title: ''
-labels: docs
+labels: documentation
 assignees: ''

 ---
@@ -19,10 +19,10 @@ assignees: ''

 <!-- make sure this issue is not redundant or obsolete -->

- [ ] checked [latest Lix manual] or its [source code]
+- [ ] checked [latest Lix manual] \([source]\)
 - [ ] checked [documentation issues] and [recent documentation changes] for possible duplicates

-[latest Lix manual]: https://docs.lix.systems/manual/lix/nightly
-[source code]: https://git.lix.systems/lix-project/lix/src/main/doc/manual/src
+[latest Nix manual]: https://docs.lix.systems/manual/lix/nightly
+[source]: https://git.lix.systems/lix-project/lix/src/main/doc/manual/src
 [documentation issues]: https://git.lix.systems/lix-project/lix/issues?labels=151&state=all
 [recent documentation changes]: https://gerrit.lix.systems/q/p:lix+path:%22%5Edoc/manual/.*%22
@@ -9,10 +9,6 @@ GTAGS
 # ccls
 /.ccls-cache

-# auto-generated compilation database
-compile_commands.json
-rust-project.json
-
 result
 result-*

@@ -33,11 +29,3 @@ buildtime.bin
 /.pre-commit-config.yaml
 /.nocontribmsg
 /release
-
-# Rust build files when using Cargo (not actually supported for building but it spews the files anyway)
-/target/
-
-# Python compiled files from the code generators and test suite
-*.pyc
-
-**/.idea
@@ -1,2 +0,0 @@
-Fiona Behrens <me@kloenk.dev>
-Fiona Behrens <me@kloenk.dev> <me@kloenk.de>
@@ -1 +0,0 @@
-This is a file used by the dev shell shellHook in package.nix to check that this is actually a Lix repo before installing git hooks. Its contents have no meaning.
@@ -1,79 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-version = 3
-
-[[package]]
-name = "countme"
-version = "3.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7704b5fdd17b18ae31c4c1da5a2e0305a2bf17b5249300a9ee9ed7b72114c636"
-
-[[package]]
-name = "dissimilar"
-version = "1.0.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "59f8e79d1fbf76bdfbde321e902714bf6c49df88a7dda6fc682fc2979226962d"
-
-[[package]]
-name = "expect-test"
-version = "1.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e0be0a561335815e06dab7c62e50353134c796e7a6155402a64bcff66b6a5e0"
-dependencies = [
- "dissimilar",
- "once_cell",
-]
-
-[[package]]
-name = "hashbrown"
-version = "0.14.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
-
-[[package]]
-name = "lix-doc"
-version = "0.0.1"
-dependencies = [
- "expect-test",
- "rnix",
- "rowan",
-]
-
-[[package]]
-name = "once_cell"
-version = "1.19.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
-
-[[package]]
-name = "rnix"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb35cedbeb70e0ccabef2a31bcff0aebd114f19566086300b8f42c725fc2cb5f"
-dependencies = [
- "rowan",
-]
-
-[[package]]
-name = "rowan"
-version = "0.15.16"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0a542b0253fa46e632d27a1dc5cf7b930de4df8659dc6e720b647fc72147ae3d"
-dependencies = [
- "countme",
- "hashbrown",
- "rustc-hash",
- "text-size",
-]
-
-[[package]]
-name = "rustc-hash"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
-
-[[package]]
-name = "text-size"
-version = "1.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f18aa187839b2bdb1ad2fa35ead8c4c2976b64e4363c386d45ac0f7ee85c9233"
@@ -1,6 +0,0 @@
-[workspace]
-resolver = "2"
-members = ["lix/lix-doc"]
-
-[workspace.package]
-edition = "2021"
@@ -17,16 +17,13 @@ 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)

 ## License

-Lix is released under [LGPL-2.1-or-later](./COPYING).
+Lix is released under the [LGPL v2.1](./COPYING).
@@ -1,4 +1,3 @@
 bench-*.json
 bench-*.md
-perf-*.json
 nixpkgs
@@ -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)
@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+
+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
+
+# XXX: yes this is very silly. flakes~!!
+nix build --impure --expr '(builtins.getFlake "git+file:.").inputs.nixpkgs.outPath' -o bench/nixpkgs
+
+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="--extra-experimental-features 'nix-command flakes'"
+
+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
@@ -32,8 +32,8 @@
  hardware = {
    enableRedistributableFirmware = true;
    cpu.intel.updateMicrocode = true;
-    graphics.enable32Bit = true;
-    graphics.extraPackages = with pkgs; [
+    opengl.driSupport32Bit = true;
+    opengl.extraPackages = with pkgs; [
      vaapiIntel
      intel-media-driver
      intel-compute-runtime
@@ -93,17 +93,16 @@

  i18n = {
    defaultLocale = "en_US.UTF-8";
-    inputMethod.enable = true;
-    inputMethod.type = "ibus";
+    inputMethod.enabled = "ibus";
  };

  services = {
-    libinput.enable = true;
    xserver = {
      enable = true;
-      xkb.layout = "us";
-      xkb.variant = "altgr-intl";
-      xkb.options = "ctrl:nocaps";
+      layout = "us";
+      xkbVariant = "altgr-intl";
+      xkbOptions = "ctrl:nocaps";
+      libinput.enable = true;
      wacom.enable = true;
      videoDrivers = [ "modesetting" ];
      modules = [ pkgs.xf86_input_wacom ];
@@ -122,6 +121,17 @@
    '';
  };

+  sound.enable = true;
+  hardware.pulseaudio = {
+    enable = true;
+    package = pkgs.pulseaudioFull;
+    daemon.config = {
+      lock-memory = "yes";
+      realtime-scheduling = "yes";
+      rlimit-rtprio = "-1";
+    };
+  };
+
  programs = {
    light.enable = true;
    wireshark = {
@@ -136,7 +146,7 @@
  fonts.packages = with pkgs; [
    font-awesome
    noto-fonts
-    noto-fonts-cjk-sans
+    noto-fonts-cjk
    noto-fonts-emoji
    noto-fonts-extra
    dejavu_fonts
@@ -229,7 +239,7 @@
    file
    firefox
    fluidsynth
-    adwaita-icon-theme
+    gnome3.adwaita-icon-theme
    gnuplot
    graphviz
    helm
@@ -242,6 +252,7 @@
    libqalculate
    libreoffice
    man-pages
+    nheko
    nix-diff
    nix-index
    nix-output-monitor
@@ -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")
@@ -0,0 +1,54 @@
+diff --git a/pthread_stop_world.c b/pthread_stop_world.c
+index 2b45489..0e6d8ef 100644
+--- a/pthread_stop_world.c
+++ b/pthread_stop_world.c
+@@ -776,6 +776,8 @@ STATIC void GC_restart_handler(int sig)
+ /* world is stopped.  Should not fail if it isn't.                      */
+ GC_INNER void GC_push_all_stacks(void)
+ {
+    size_t stack_limit;
+    pthread_attr_t pattr;
+     GC_bool found_me = FALSE;
+     size_t nthreads = 0;
+     int i;
+@@ -868,6 +870,40 @@ GC_INNER void GC_push_all_stacks(void)
+             hi = p->altstack + p->altstack_size;
+ #         endif
+           /* FIXME: Need to scan the normal stack too, but how ? */
+        } else {
+          #ifdef HAVE_PTHREAD_ATTR_GET_NP
+          if (pthread_attr_init(&pattr) != 0) {
+            ABORT("GC_push_all_stacks: pthread_attr_init failed!");
+          }
+          if (pthread_attr_get_np(p->id, &pattr) != 0) {
+            ABORT("GC_push_all_stacks: pthread_attr_get_np failed!");
+          }
+          #else
+          if (pthread_getattr_np(p->id, &pattr)) {
+            ABORT("GC_push_all_stacks: pthread_getattr_np failed!");
+          }
+          #endif
+          if (pthread_attr_getstacksize(&pattr, &stack_limit)) {
+            ABORT("GC_push_all_stacks: pthread_attr_getstacksize failed!");
+          }
+          if (pthread_attr_destroy(&pattr)) {
+            ABORT("GC_push_all_stacks: pthread_attr_destroy failed!");
+          }
+          // When a thread goes into a coroutine, we lose its original sp until
+          // control flow returns to the thread.
+          // While in the coroutine, the sp points outside the thread stack,
+          // so we can detect this and push the entire thread stack instead,
+          // as an approximation.
+          // We assume that the coroutine has similarly added its entire stack.
+          // This could be made accurate by cooperating with the application
+          // via new functions and/or callbacks.
+          #ifndef STACK_GROWS_UP
+            if (lo >= hi || lo < hi - stack_limit) { // sp outside stack
+              lo = hi - stack_limit;
+            }
+          #else
+          #error "STACK_GROWS_UP not supported in boost_coroutine2 (as of june 2021), so we don't support it in Nix."
+          #endif
+         }
+ #       ifdef STACKPTR_CORRECTOR_AVAILABLE
+           if (GC_sp_corrector != 0)
@@ -0,0 +1,90 @@
+#include "FixIncludes.hh"
+#include <clang-tidy/ClangTidyCheck.h>
+#include <clang/Basic/Diagnostic.h>
+#include <clang/Basic/SourceManager.h>
+#include <clang/Lex/PPCallbacks.h>
+#include <clang/Lex/Preprocessor.h>
+#include <llvm/ADT/StringRef.h>
+#include <llvm/Support/Debug.h>
+#include <memory>
+#include <set>
+#include <string>
+
+namespace nix::clang_tidy {
+
+using namespace clang;
+using namespace clang::tidy;
+
+class FixIncludesCallbacks : public PPCallbacks {
+public:
+  ClangTidyCheck &Check;
+  Preprocessor &PP;
+  FixIncludesCallbacks(ClangTidyCheck &Check, Preprocessor &PP)
+      : Check(Check), PP(PP) {}
+
+private:
+  bool Ignore = false;
+  virtual void LexedFileChanged(FileID FID, LexedFileChangeReason Reason,
+                                SrcMgr::CharacteristicKind FileType,
+                                FileID PrevFID, SourceLocation Loc) override;
+
+  virtual void InclusionDirective(SourceLocation HashLoc,
+                                  const Token &IncludeTok, StringRef FileName,
+                                  bool IsAngled, CharSourceRange FilenameRange,
+                                  OptionalFileEntryRef File,
+                                  StringRef SearchPath, StringRef RelativePath,
+                                  const Module *Imported,
+                                  SrcMgr::CharacteristicKind FileType) override;
+};
+
+void FixIncludesCallbacks::LexedFileChanged(FileID, LexedFileChangeReason,
+                                            SrcMgr::CharacteristicKind FileType,
+                                            FileID, SourceLocation) {
+  Ignore = FileType != SrcMgr::C_User;
+}
+
+void FixIncludesCallbacks::InclusionDirective(
+    SourceLocation, const Token &, StringRef FileName, bool IsAngled,
+    CharSourceRange FilenameRange, OptionalFileEntryRef File, StringRef,
+    StringRef, const Module *, SrcMgr::CharacteristicKind) {
+  if (Ignore)
+    return;
+
+  // FIXME: this is kinda evil, but this is a one-time fixup
+  const std::vector<std::string> SourceDirs = {"src/", "include/lix/"};
+
+  const auto Bracketize = [IsAngled](StringRef s) {
+    return IsAngled ? ("<" + s + ">").str() : ("\"" + s + "\"").str();
+  };
+
+  for (const auto &SourceDir : SourceDirs) {
+    const bool IsAlreadyFixed = FileName.starts_with("lix/lib");
+    if (File && File->getNameAsRequested().contains(SourceDir) &&
+        !IsAlreadyFixed) {
+      StringRef Name = File->getNameAsRequested();
+      auto Idx = Name.find(SourceDir);
+      assert(Idx != std::string::npos);
+      std::string Suffix = Name.drop_front(Idx + SourceDir.length()).str();
+
+      if (!Suffix.starts_with("lib")) {
+        llvm::dbgs() << "ignored: " << Suffix << "\n";
+        return;
+      }
+
+      Suffix = "lix/" + Suffix;
+
+      auto Diag = Check.diag(FilenameRange.getBegin(),
+                             "include needs to specify the source subdir");
+
+      Diag << FilenameRange
+           << FixItHint::CreateReplacement(FilenameRange, Bracketize(Suffix));
+    }
+  }
+}
+
+void FixIncludesCheck::registerPPCallbacks(const SourceManager &,
+                                           Preprocessor *PP, Preprocessor *) {
+  PP->addPPCallbacks(std::make_unique<FixIncludesCallbacks>(*this, *PP));
+}
+
+}; // namespace nix::clang_tidy
@@ -0,0 +1,21 @@
+#pragma once
+///@file
+
+#include <clang-tidy/ClangTidyCheck.h>
+#include <clang/ASTMatchers/ASTMatchFinder.h>
+#include <llvm/ADT/StringRef.h>
+
+namespace nix::clang_tidy {
+
+using namespace clang;
+using namespace clang::tidy;
+
+class FixIncludesCheck : public ClangTidyCheck {
+    public:
+    FixIncludesCheck(StringRef Name, ClangTidyContext *Context)
+            : ClangTidyCheck(Name, Context) {}
+
+    void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) override;
+};
+
+};
@@ -1,10 +1,7 @@
 #include <clang-tidy/ClangTidyModule.h>
 #include <clang-tidy/ClangTidyModuleRegistry.h>
-#include "DisallowedDecls.hh"
-#include "ForeignExceptions.hh"
+#include "FixIncludes.hh"
 #include "HasPrefixSuffix.hh"
-#include "CharPtrCast.hh"
-#include "NeverAsync.hh"

 namespace nix::clang_tidy {
 using namespace clang;
@@ -14,10 +11,7 @@ class NixClangTidyChecks : public ClangTidyModule {
    public:
        void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
            CheckFactories.registerCheck<HasPrefixSuffixCheck>("lix-hasprefixsuffix");
-            CheckFactories.registerCheck<CharPtrCastCheck>("lix-charptrcast");
-            CheckFactories.registerCheck<NeverAsync>("lix-never-async");
-            CheckFactories.registerCheck<DisallowedDeclsCheck>("lix-disallowed-decls");
-            CheckFactories.registerCheck<ForeignExceptions>("lix-foreign-exceptions");
+            CheckFactories.registerCheck<FixIncludesCheck>("lix-fixincludes");
        }
 };

@@ -10,13 +10,13 @@ goal and is there as an example), `HasPrefixSuffixCheck`.
 One file:

 ```
-ninja -C build && clang-tidy --checks='-*,lix-*' --load=build/liblix-clang-tidy.so -p ../../build -header-filter '\.\./lix/.*\.h' --fix ../../lix/libcmd/installables.cc
+ninja -C build && clang-tidy --checks='-*,lix-*' --load=build/liblix-clang-tidy.so -p ../compile_commands.json -header-filter '\.\./src/.*\.h' --fix ../src/libcmd/installables.cc
 ```

 Several files, in parallel:

 ```
-ninja -C build && run-clang-tidy -checks='-*,lix-*' -load=build/liblix-clang-tidy.so -p ../../build -header-filter '\.\./lix/.*\.h' -fix ../../lix | tee -a clang-tidy-result
+ninja -C build && run-clang-tidy -checks='-*,lix-*' -load=build/liblix-clang-tidy.so -p .. -header-filter '\.\./src/.*\.h' -fix ../src | tee -a clang-tidy-result
 ```

 ## Resources
@@ -40,7 +40,7 @@ enable output     dump
 match callExpr(callee(functionDecl(hasName("hasPrefix"))), optionally(hasArgument( 0, cxxConstructExpr(hasDeclaration(functionDecl(hasParameter(0, parmVarDecl(hasType(asString("const char *"))).bind("meow2"))))))))
 ```

-Then run, e.g. `clang-query --preload hasprefix.query -p compile_commands.json lix/libcmd/installables.cc`.
+Then run, e.g. `clang-query --preload hasprefix.query -p compile_commands.json src/libcmd/installables.cc`.

 With this you can iterate a query before writing it in C++ and suffering from
 C++.
@@ -0,0 +1,13 @@
+project('lix-clang-tidy', ['cpp', 'c'],
+  version : '0.1',
+  default_options : ['warning_level=3', 'cpp_std=c++20'])
+
+llvm = dependency('Clang', version: '>= 14', modules: ['libclang'])
+sources = files(
+  'HasPrefixSuffix.cc',
+  'LixClangTidyChecks.cc',
+  'FixIncludes.cc',
+)
+
+shared_module('lix-clang-tidy', sources,
+  dependencies: llvm)
@@ -20,7 +20,7 @@ OUTPUT_DIRECTORY       = @docdir@
 # for a project that appears at the top of each page and should give viewer a
 # quick idea about the purpose of the project. Keep the description short.

-PROJECT_BRIEF          = "Lix: A modern, delicious implementation of the Nix package manager; unstable internal interfaces"
+PROJECT_BRIEF          = "Nix, the purely functional package manager; unstable internal interfaces"

 # If the GENERATE_LATEX tag is set to YES, doxygen will generate LaTeX output.
 # The default value is: YES.
@@ -33,7 +33,32 @@ GENERATE_LATEX         = NO
 # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
 # Note: If this tag is empty the current directory is searched.

-INPUT                  = @INPUT_PATHS@
+# FIXME Make this list more maintainable somehow. We could maybe generate this
+# in the Makefile, but we would need to change how `.in` files are preprocessed
+# so they can expand variables despite configure variables.
+
+INPUT                  = \
+  src/libcmd \
+  src/libexpr \
+  src/libexpr/flake \
+  tests/unit/libexpr \
+  tests/unit/libexpr/value \
+  tests/unit/libexpr/test \
+  tests/unit/libexpr/test/value \
+  src/libexpr/value \
+  src/libfetchers \
+  src/libmain \
+  src/libstore \
+  src/libstore/build \
+  src/libstore/builtins \
+  tests/unit/libstore \
+  tests/unit/libstore/test \
+  src/libutil \
+  tests/unit/libutil \
+  tests/unit/libutil/test \
+  src/nix \
+  src/nix-env \
+  src/nix-store

 # If the MACRO_EXPANSION tag is set to YES, doxygen will expand all macro names
 # in the source code. If set to NO, only conditional compilation will be
@@ -72,15 +97,3 @@ EXPAND_AS_DEFINED      = \
  DECLARE_WORKER_SERIALISER \
  DECLARE_SERVE_SERIALISER \
  LENGTH_PREFIXED_PROTO_HELPER
-
-# The STRIP_FROM_PATH tag can be used to strip a user-defined part of the path.
-# Stripping is only done if one of the specified strings matches the left-hand
-# part of the path. The tag can be used to show relative paths in the file list.
-# If left blank the directory from which doxygen is run is used as the path to
-# strip.
-#
-# Note that you can specify absolute paths here, but also relative paths, which
-# will be relative from the directory where doxygen is started.
-# This tag requires that the tag FULL_PATH_NAMES is set to YES.
-
-STRIP_FROM_PATH        = "@PROJECT_SOURCE_ROOT@"
@@ -1,35 +1,3 @@
-internal_api_sources = [
-  'lix/libcmd',
-  'lix/libexpr',
-  'lix/libexpr/flake',
-  'tests/unit/libexpr',
-  'tests/unit/libexpr/value',
-  'tests/unit/libexpr/test',
-  'tests/unit/libexpr/test/value',
-  'lix/libexpr/value',
-  'lix/libfetchers',
-  'lix/libmain',
-  'lix/libstore',
-  'lix/libstore/build',
-  'lix/libstore/builtins',
-  'tests/unit/libstore',
-  'tests/unit/libstore/test',
-  'lix/libutil',
-  'tests/unit/libutil',
-  'tests/unit/libutil/test',
-  'lix/nix',
-  'lix/nix-env',
-  'lix/nix-store',
-]
-
-# We feed Doxygen absolute paths so it can be invoked from any working directory.
-internal_api_sources_absolute = []
-foreach src : internal_api_sources
-  internal_api_sources_absolute += '"' + (meson.project_source_root() / src) + '"'
-endforeach
-
-internal_api_sources_oneline = ' \\\n  '.join(internal_api_sources_absolute)
-
 doxygen_cfg = configure_file(
  input : 'doxygen.cfg.in',
  output : 'doxygen.cfg',
@@ -37,16 +5,22 @@ doxygen_cfg = configure_file(
    'PACKAGE_VERSION': meson.project_version(),
    'RAPIDCHECK_HEADERS': rapidcheck_meson.get_variable('includedir'),
    'docdir' : meson.current_build_dir(),
-    'INPUT_PATHS' : internal_api_sources_oneline,
-    'PROJECT_SOURCE_ROOT' : meson.project_source_root(),
  },
 )

 internal_api_docs = custom_target(
  'internal-api-docs',
  command : [
-    doxygen.full_path(),
-    '@INPUT0@',
+    bash,
+    # Meson can you please just give us a `workdir` argument to custom targets...
+    '-c',
+    # We have to prefix the doxygen_cfg path with the project build root
+    # because of the cd in front.
+    'cd @0@ && @1@ @2@/@INPUT0@'.format(
+      meson.project_source_root(),
+      doxygen.full_path(),
+      meson.project_build_root(),
+    ),
  ],
  input : [
    doxygen_cfg,
@@ -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.
@@ -3,19 +3,11 @@
 #
 # It's used for crediting people accurately in release notes. The release notes
 # script will link to forgejo, then to GitHub if forgejo is not present.
-#
-# When adding someone from outside the Lix project, you generally want to simply link their GitHub profile without adding a display name unless they are well-known in the community by that display name.
-#
-# See doc/manual/src/contributing/hacking.md for more documentation on this file's format and typical usage.
 9999years:
  display_name: wiggles
  forgejo: rbt
  github: 9999years

-9p4:
-  display_name: Ersei Saggi
-  github: 9p4
-
 Artturin:
  github: Artturin

@@ -40,39 +32,14 @@ alois31:
  forgejo: alois31
  github: alois31

-andrewhamon:
-  display_name: Andrew Hamon
-  github: andrewhamon
-
 artemist:
  display_name: Artemis Tosini
  forgejo: artemist

-bb010g:
-  display_name: Dusk Banks
-  forgejo: bb010g
-  github: bb010g
-
-blitz:
-  display_name: Julian Stecklina
-  github: blitz
-
 cole-h:
  display_name: Cole Helbling
  github: cole-h

-delan:
-  display_name: delan
-  forgejo: delan
-  github: delan
-
-delroth:
-  github: delroth
-
-detroyejr:
-  display_name: Jonathan De Troye
-  github: detroyejr
-
 edolstra:
  display_name: Eelco Dolstra
  github: edolstra
@@ -81,14 +48,6 @@ ericson:
  display_name: John Ericson
  github: ericson2314

-gilice:
-  forgejo: gilice
-
-goldstein:
-  display_name: goldstein
-  forgejo: goldstein
-  github: GoldsteinE
-
 horrors:
  display_name: eldritch horrors
  forgejo: pennae
@@ -97,52 +56,10 @@ horrors:
 iFreilicht:
  github: iFreilicht

-ian-h-chamberlain:
-  forgejo: ian-h-chamberlain
-  github: ian-h-chamberlain
-
-infinisil:
-  github: infinisil
-
-isabelroses:
-  forgejo: isabelroses
-  github: isabelroses
-
 jade:
  forgejo: jade
  github: lf-

-just1602:
-  forgejo: just1602
-
-kfears:
-  display_name: KFears
-  forgejo: kfearsoff
-  github: kfearsoff
-
-kiara:
-  github: KiaraGrouwstra
-
-kjeremy:
-  github: kjeremy
-
-kloenk:
-  display_name: Fiona Behrens
-  forgejo: kloenk
-  github: kloenk
-
-lheckemann:
-  forgejo: lheckemann
-  github: lheckemann
-
-lily:
-  forgejo: lilyinstarlight
-  github: lilyinstarlight
-
-lilyball:
-  forgejo: lilyball
-  github: lilyball
-
 lovesegfault:
  github: lovesegfault

@@ -158,47 +75,14 @@ midnightveil:
  forgejo: midnightveil
  github: midnightveil

-nan-git:
-  display_name: NaN-git
-  github: NaN-git
-
 ncfavier:
  github: ncfavier

-not-my-profile:
-  display_name: Martin Fischer
-  github: not-my-profile
-
-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
-
 r-vdp:
  github: r-vdp

@@ -211,18 +95,6 @@ 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
@@ -235,28 +107,9 @@ valentin:
  display_name: Valentin Gagarin
  github: fricklerhandwerk

-vigress8:
-  display_name: Vigress
-  forgejo: vigress8
-  github: vigress8
-
-vlinkz:
-  display_name: Victor Fuentes
-  forgejo: vlinkz
-  github: vlinkz
-
 winter:
  forgejo: winter
  github: winterqt

-xanderio:
-  github: xanderio
-
-yorickvp:
-  github: yorickvp
-
 yshui:
  github: yshui
-
-zimbatm:
-  github: zimbatm
@@ -0,0 +1,37 @@
+let
+  inherit (builtins) concatStringsSep attrValues mapAttrs;
+  inherit (import ./utils.nix) optionalString squash;
+in
+
+builtinsInfo:
+let
+  showBuiltin =
+    name:
+    {
+      doc,
+      type,
+      impure-only,
+    }:
+    let
+      type' = optionalString (type != null) " (${type})";
+
+      impureNotice = optionalString impure-only ''
+        > **Note**
+        >
+        > Not available in [pure evaluation mode](@docroot@/command-ref/conf-file.md#conf-pure-eval).
+      '';
+    in
+    squash ''
+      <dt id="builtins-${name}">
+        <a href="#builtins-${name}"><code>${name}</code></a>${type'}
+      </dt>
+      <dd>
+
+      ${doc}
+
+      ${impureNotice}
+
+      </dd>
+    '';
+in
+concatStringsSep "\n" (attrValues (mapAttrs showBuiltin builtinsInfo))
@@ -0,0 +1,35 @@
+let
+  inherit (builtins) concatStringsSep attrValues mapAttrs;
+  inherit (import ./utils.nix) optionalString squash;
+in
+
+builtinsInfo:
+let
+  showBuiltin =
+    name:
+    {
+      doc,
+      args,
+      arity,
+      experimental-feature,
+    }:
+    let
+      experimentalNotice = optionalString (experimental-feature != null) ''
+        This function is only available if the [${experimental-feature}](@docroot@/contributing/experimental-features.md#xp-feature-${experimental-feature}) experimental feature is enabled.
+      '';
+    in
+    squash ''
+      <dt id="builtins-${name}">
+        <a href="#builtins-${name}"><code>${name} ${listArgs args}</code></a>
+      </dt>
+      <dd>
+
+      ${doc}
+
+      ${experimentalNotice}
+
+      </dd>
+    '';
+  listArgs = args: concatStringsSep " " (map (s: "<var>${s}</var>") args);
+in
+concatStringsSep "\n" (attrValues (mapAttrs showBuiltin builtinsInfo))
@@ -1,134 +1,26 @@
-with builtins;
-
 let
-  splitLines = s: filter (x: !isList x) (split "\n" s);
-
-  concatStrings = concatStringsSep "";
-
-  replaceStringsRec =
-    from: to: string:
-    # recursively replace occurrences of `from` with `to` within `string`
-    # example:
-    #     replaceStringRec "--" "-" "hello-----world"
-    #     => "hello-world"
-    let
-      replaced = replaceStrings [ from ] [ to ] string;
-    in
-    if replaced == string then string else replaceStringsRec from to replaced;
-
-  squash = replaceStringsRec "\n\n\n" "\n\n";
-
-  trim =
-    string:
-    # trim trailing spaces and squash non-leading spaces
-    let
-      trimLine =
-        line:
-        let
-          # separate leading spaces from the rest
-          parts = split "(^ *)" line;
-          spaces = head (elemAt parts 1);
-          rest = elemAt parts 2;
-          # drop trailing spaces
-          body = head (split " *$" rest);
-        in
-        spaces + replaceStringsRec "  " " " body;
-    in
-    concatStringsSep "\n" (map trimLine (splitLines string));
-
-  # FIXME: O(n^2)
-  unique = foldl' (acc: e: if elem e acc then acc else acc ++ [ e ]) [ ];
-
-  nameValuePair = name: value: { inherit name value; };
-
-  filterAttrs =
-    pred: set:
-    listToAttrs (
-      concatMap (
-        name:
-        let
-          v = set.${name};
-        in
-        if pred name v then [ (nameValuePair name v) ] else [ ]
-      ) (attrNames set)
-    );
-
-  optionalString = cond: string: if cond then string else "";
-
-  showSetting =
-    { inlineHTML }:
-    name:
-    {
-      description,
-      documentDefault,
-      defaultValue,
-      aliases,
-      value,
-      experimentalFeature,
-    }:
-    let
-      result = squash ''
-        - ${
-          if inlineHTML then ''<span id="conf-${name}">[`${name}`](#conf-${name})</span>'' else ''`${name}`''
-        }
-
-        ${indent "  " body}
-      '';
-
-      experimentalFeatureNote = optionalString (experimentalFeature != null) ''
-        > **Warning**
-        > This setting is part of an
-        > [experimental feature](@docroot@/contributing/experimental-features.md).
-
-        To change this setting, you need to make sure the corresponding experimental feature,
-        [`${experimentalFeature}`](@docroot@/contributing/experimental-features.md#xp-feature-${experimentalFeature}),
-        is enabled.
-        For example, include the following in [`nix.conf`](#):
-
-        ```
-        extra-experimental-features = ${experimentalFeature}
-        ${name} = ...
-        ```
-      '';
-
-      # separate body to cleanly handle indentation
-      body = ''
-        ${description}
-
-        ${experimentalFeatureNote}
-
-        **Default:** ${showDefault documentDefault defaultValue}
-
-        ${showAliases aliases}
-      '';
-
-      showDefault =
-        documentDefault: defaultValue:
-        if documentDefault then
-          # a StringMap value type is specified as a string, but
-          # this shows the value type. The empty stringmap is `null` in
-          # JSON, but that converts to `{ }` here.
-          if defaultValue == "" || defaultValue == [ ] || isAttrs defaultValue then
-            "*empty*"
-          else if isBool defaultValue then
-            if defaultValue then "`true`" else "`false`"
-          else
-            "`${toString defaultValue}`"
-        else
-          "*machine-specific*";
-
-      showAliases =
-        aliases:
-        optionalString (aliases != [ ])
-          "**Deprecated alias:** ${(concatStringsSep ", " (map (s: "`${s}`") aliases))}";
-    in
-    result;
-
-  indent =
-    prefix: s: concatStringsSep "\n" (map (x: if x == "" then x else "${prefix}${x}") (splitLines s));
-
-  showSettings =
-    args: settingsInfo: concatStrings (attrValues (mapAttrs (showSetting args) settingsInfo));
+  inherit (builtins)
+    attrNames
+    attrValues
+    fromJSON
+    listToAttrs
+    mapAttrs
+    concatStringsSep
+    concatMap
+    length
+    lessThan
+    replaceStrings
+    sort
+    ;
+  inherit (import ./utils.nix)
+    concatStrings
+    optionalString
+    filterAttrs
+    trim
+    squash
+    unique
+    showSettings
+    ;
 in

 inlineHTML: commandDump:
@@ -0,0 +1,9 @@
+with builtins;
+with import ./utils.nix;
+
+let
+  showExperimentalFeature = name: doc: ''
+    - [`${name}`](@docroot@/contributing/experimental-features.md#xp-feature-${name})
+  '';
+in
+xps: indent "  " (concatStrings (attrValues (mapAttrs showExperimentalFeature xps)))
@@ -0,0 +1,13 @@
+with builtins;
+with import ./utils.nix;
+
+let
+  showExperimentalFeature =
+    name: doc:
+    squash ''
+      ## [`${name}`]{#xp-feature-${name}}
+
+      ${doc}
+    '';
+in
+xps: (concatStringsSep "\n" (attrValues (mapAttrs showExperimentalFeature xps)))
@@ -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',
@@ -16,21 +15,67 @@ nix_eval_for_docs_common = nix_for_docs + [
 ]
 nix_eval_for_docs = nix_eval_for_docs_common + '--raw'

+conf_file_json = custom_target(
+  command : nix_for_docs + [ 'show-config', '--json' ],
+  capture : true,
+  output : 'conf-file.json',
+  env : nix_env_for_docs,
+)
+
+nix_conf_file_md_body = custom_target(
+  command : nix_eval_for_docs + [
+    '--expr',
+    '(import @INPUT0@).showSettings { inlineHTML = true; } (builtins.fromJSON (builtins.readFile @INPUT1@))',
+  ],
+  capture : true,
+  input : [
+    'utils.nix',
+    conf_file_json,
+  ],
+  output : 'conf-file.md.body',
+  env : nix_env_for_docs,
+)
+
+nix_conf_file_md = custom_target(
+  command : [ 'cat', '@INPUT@' ],
+  capture : true,
+  input : [
+    'src/command-ref/conf-file.md',
+    nix_conf_file_md_body,
+  ],
+  output : 'conf-file.md',
+)
+
+nix_exp_features_json = custom_target(
+  command : [ nix, '__dump-xp-features' ],
+  capture : true,
+  output : 'xp-features.json',
+)
+
+language_json = custom_target(
+  command: [nix, '__dump-language'],
+  output : 'language.json',
+  capture : true,
+  env : nix_env_for_docs,
+)
+
 nix3_cli_json = custom_target(
  command : [ nix, '__dump-cli' ],
  capture : true,
  output : 'nix.json',
  env : nix_env_for_docs,
-  # FIXME: put the actual lib targets in here? meson have introspection challenge 2024 though.
-  build_always_stale : true,
 )

 generate_manual_deps = files(
  'generate-deps.py',
 )

-# Generates new-cli pages  and conf-file.md.
+# Generates builtins.md and builtin-constants.md.
+subdir('src/language')
+# Generates new-cli pages, experimental-features-shortlist.md, and conf-file.md.
 subdir('src/command-ref')
+# Generates experimental-feature-descriptions.md.
+subdir('src/contributing')
 # Generates rl-next-generated.md.
 subdir('src/release-notes')

@@ -61,31 +106,29 @@ manual = custom_target(
    nix3_cli_files,
    experimental_features_shortlist_md,
    experimental_feature_descriptions_md,
-    deprecated_features_shortlist_md,
-    deprecated_feature_descriptions_md,
    conf_file_md,
    builtins_md,
    builtin_constants_md,
    rl_next_generated,
-    nix,
  ],
  output : [
    'manual',
    'markdown',
  ],
-  install : true,
-  install_dir : [
-    datadir / 'doc/nix',
-    false,
-  ],
  depfile : 'manual.d',
  env : {
    'RUST_LOG': 'info',
    'MDBOOK_SUBSTITUTE_SEARCH': meson.current_build_dir() / 'src',
  },
 )
+manual_html = manual[0]
 manual_md = manual[1]

+install_subdir(
+  manual_html.full_path(),
+  install_dir : datadir / 'doc/nix',
+)
+
 nix_nested_manpages = [
  [ 'nix-env',
    [
@@ -143,7 +186,6 @@ foreach command : nix_nested_manpages
      ],
      input : [
        manual_md,
-        nix,
      ],
      output : command[0] + '-' + page + '.1',
      install : true,
@@ -256,7 +298,6 @@ foreach page : nix3_manpages
    input : [
      'render-manpage.sh',
      manual_md,
-      nix,
    ],
    output : page + '.1',
    install : true,
@@ -300,7 +341,6 @@ foreach entry : nix_manpages
      'render-manpage.sh',
      manual_md,
      entry.get(3, []),
-      nix,
    ],
    output : '@0@.@1@'.format(entry[0], entry[1]),
    install : true,
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh

 set -euo pipefail

@@ -345,7 +345,7 @@ const redirects = {
    "linux": "uninstall.html#linux",
    "macos": "uninstall.html#macos",
    "uninstalling": "uninstall.html",
-  },
+  }
  "contributing/hacking.html": {
    "nix-with-flakes": "#building-nix-with-flakes",
    "classic-nix": "#building-nix",
@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh

 set -euo pipefail

@@ -1,16 +0,0 @@
---
-synopsis: First argument to `--arg`/`--argstr` must be a valid Nix identifier
-issues: [fj#496]
-category: "Breaking Changes"
-credits: [ma27]
---
-
-The first argument to `--arg`/`--argstr` must be a valid Nix identifier, i.e.
-`nix-build --arg config.allowUnfree true` is now rejected.
-
-This is because that invocation is a false friend since it doesn't set
-`{ config = { allowUnfree = true; }; }`, but `{ "config.allowUnfree" = true; }`.
-
-The idea is to change the behavior to the latter in the long-term. For that,
-non-identifiers started giving a warning since 2.92 and are now rejected to give people
-who depend on that a chance to notice and potentially weigh in on the discussion.
@@ -1,20 +0,0 @@
---
-synopsis: "Improved susbtituter query speed"
-issues: []
-cls: []
-category: Improvements
-credits: [horrors]
---
-
-The code used to query substituters for derivations has been rewritten slightly
-to take advantage of our asynchronous runtime. Such queries run for every build
-that could download from substituters and processes every derivation that isn't
-yet present on the local system. Previously Lix would use `http-connections` to
-limit query concurrency, even for modern caches that support HTTP/2 and have no
-limit on how many queries can be run concurrently on one single connection. Lix
-no longer does this, resulting in approximately 60% reduction in query time for
-medium-sized closures (e.g. NixOS system closures) during testing, although the
-exact number depends greatly on local network latency and generally improves as
-latency increases. Unlike previously setting `http-connections` to `1` or other
-low values no longer brings a massive penalty in query performance if the cache
-in use by the querying system supports HTTP/2 (as e.g. `cache.nixos.org` does).
@@ -1,12 +0,0 @@
---
-synopsis: "`build-dir` no longer defaults to `temp-dir`"
-cls: [3453]
-category: "Fixes"
-credits: [horrors]
---
-
-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).
@@ -1,69 +0,0 @@
---
-synopsis: New cgroup delegation model
-issues: [fj#537, fj#77]
-cls: [3230]
-category: "Breaking Changes"
-credits: [raito, horrors, lheckemann]
---
-
-Builds using cgroups (i.e. `use-cgroups = true` and the experimental feature
-`cgroups`) now always delegate a cgroup tree to the sandbox.
-
-Compared to the original C++ Nix project, our delegation includes the
-`subtree_control` file as well, which means that the sandbox can disable
-certain controllers in its own cgroup tree.
-
-This is a breaking change because this requires the Nix daemon to run with an
-already delegated cgroup tree by the service manager.
-
-## How to setup the cgroup tree with systemd?
-
-systemd offers knobs to perform the required setup using:
-
-```
-[Service]
-Delegate=yes
-DelegateSubtree=supervisor
-```
-
-These directives are now included in our systemd packaging.
-
-## What about using Nix as root without connecting to the daemon?
-
-Builds run as `root` without connecting to the daemon relying on the cgroup
-feature are now broken, i.e.
-
-```console
-# nix-build --use-cgroups --sandbox ... # will not work
-```
-
-Consider doing instead:
-
-```console
-# systemd-run --same-dir --wait -p Delegate=yes -p DelegateSubgroup=supervisor nix-build --use-cgroups ...
-```
-
-If you need to disable cgroups temporarily, remember that you can do
-`NIX_CONF='include /etc/nix/nix.conf\nuse-cgroups = false' nix-build ...` or
-`nix-build --no-use-cgroups ...`.
-
-## What about other service managers than systemd?
-
-systemd has a [documentation](https://systemd.io/CGROUP_DELEGATION/) on how to
-handle cgroup delegation from service management perspective.
-
-If your service manager adheres to systemd semantics, e.g. writing an extended
-attribute `user.delegate=1` on the delegated cgroup tree directory and moving
-the `nix-daemon` process inside a cgroup tree to respect the inner process
-rule, then, the feature will work as well.
-
-## Why is the cgroup feature still experimental?
-
-While the cgroup feature unlocks many use cases, its behavior and integration (e.g. user experience), especially at scale on build farms or in multi-tenant environments, are not yet fully matured. There’s also potential for deeper systemd integration (e.g. using slices and scopes) that has not been fully explored.
-
-To avoid locking in an unstable interface, we’re keeping the experimental flag until we have validated the feature across a broader range of scenarios, including but not limited to:
-
-* Nix as root
-* Hydra-style build farms
-* Forgejo CI runners
-* Shared remote builders
@@ -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.
@@ -1,13 +0,0 @@
---
-synopsis: "nix-store --delete: always remove obsolete hardlinks"
-issues: []
-cls: [3188]
-category: Fixes
-credits: [lheckemann]
---
-
-Deleting specific paths using `nix-store --delete` or `nix store
-delete` previously did not delete hard links created by `nix-store
--optimise` even if they became obsolete, unless _all_ of the given
-paths were deleted successfully. Now, hard links are always cleaned
-up, even if some of the given paths could not be deleted.
@@ -1,24 +0,0 @@
---
-synopsis: "Report GC statistics correctly"
-issues: []
-cls: [3188]
-category: Fixes
-credits: [lheckemann]
---
-
-Deleting specific paths using `nix-store --delete` or `nix store delete` previously did
-not report statistics correctly when some of the paths could not be deleted, even if
-others were deleted:
-
-```
-$ nix store delete /nix/store/9bwryidal9q3g91cjm6xschfn4ikd82q-hello-2.12.1 --delete-closure -v
-finding garbage collector roots...
-deleting '/nix/store/9bwryidal9q3g91cjm6xschfn4ikd82q-hello-2.12.1'
-0 store paths deleted, 0.00 MiB freed
-error: Cannot delete some of the given paths because they are still alive. Paths not deleted:
-         k9bxzr1l92r5y6mihrkbpbr3fmc8qszx-libidn2-2.3.8
-         mbx9ii53lzjlrsnlrfmzpwm33ynljwdn-libunistring-1.3
-         rf8hcy6bldxdqc0g6q1dcka1vh47x69s-xgcc-14.2.1.20250322-libgcc
-         vbrdc5wgzn0w1zdp10xd2favkjn5fk7y-glibc-2.40-66
-       To find out why, use nix-store --query --roots and nix-store --query --referrers.
-```
@@ -1,24 +0,0 @@
---
-synopsis: Repl debugger uses `--ignore-try` by default
-issues: [lix#666]
-cls: [3488]
-category: Breaking Changes
-credits: [jade]
---
-Previously, using the debugger meant that exceptions thrown in `builtins.tryEval` would trigger the debugger.
-
-However, this caught nixpkgs initialization code, which is unhelpful in the majority of cases, so we changed the default.
-
-To get the old behaviour, use `--no-ignore-try`.
-
-```
-$ nix repl --debugger --expr 'with import <nixpkgs> {}; pkgs.hello'
-Lix 2.94.0-dev-pre20250625-9a59106
-Type :? for help.
-error: file 'nixpkgs-overlays' was not found in the Nix search path (add it using $NIX_PATH or -I)
-
-This exception occurred in a 'tryEval' call. Use --ignore-try to skip these.
-
-Added 13 variables.
-nix-repl>
-```
@@ -1,25 +0,0 @@
---
-synopsis: "Fallback to safe temp dir when build-dir is unwritable"
-issues: [fj#876]
-cls: [3501]
-category: "Fixes"
-credits: ["raito", "horrors"]
---
-
-Non-daemon builds started failing with a permission error after introducing the `build-dir` option:
-
-```
-$ 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.
@@ -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.
@@ -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.
@@ -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.
@@ -1,12 +0,0 @@
---
-synopsis: "Add --raw flag to `nix-instantiate --eval` for unescaped output"
-issues: []
-prs: [gh#12119]
-cls: [2886]
-category: Improvements
-credits: [not-my-profile, infinisil, raito]
---
-
-The `nix-instantiate --eval` command now supports a `--raw` flag. When used,
-the result must be coercible to a string (as with `${...}`) and is printed
-verbatim, without quotes or escaping.
@@ -1,12 +0,0 @@
---
-synopsis: Allow `nix store ls` to read nar listings from binary cache stores.
-issues: []
-cls: [3225]
-category: Improvements
-credits: [vlinkz]
---
-
-The `nix store ls` command now supports reading `.ls` nar listings from binary cache stores.
-If a listing is detected for the store path being queried, the nar is no longer downloaded.
-These nar listings are available in binary cache stores where the `write-nar-listing` option is
-enabled, such as cache.nixos.org.
@@ -1,20 +0,0 @@
---
-synopsis: "Fixed output derivations can be run using `pasta` network isolation"
-cls: [3452]
-issues: [fj#285]
-category: "Breaking Changes"
-credits: [horrors, puck]
---
-
-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/
@@ -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.
@@ -1,20 +0,0 @@
---
-synopsis: Remove support for daemon protocols before 2.18
-issues: []
-cls: [3249]
-significance: significant
-category: "Breaking Changes"
-credits: [horrors]
---
-
-Support for daemon wire protocols belonging to Nix 2.18 or older have been
-removed. This impacts clients connecting to the local daemon socket or any
-remote builder configured using the `ssh-ng` protocol. Builders configured
-with the `ssh` protocol are still accessible from clients such as Nix 2.3.
-Additionally Lix will not be able to connect to an old daemon locally, and
-remote build connections to old daemons is likewise limited to `ssh` urls.
-
-We have decided to take this step because the old protocols are very badly
-tested (if at all), maintenance overhead is high, and a number of problems
-with their design makes it infeasible to remain backwards compatible while
-we move Lix to a more modern RPC mechanism with better versioning support.
@@ -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.
@@ -1,20 +0,0 @@
---
-synopsis: "repl-overlays now work in the debugger for flakes"
-issues: [fj#777]
-cls: [3398]
-category: Fixes
-credits: [jade]
---
-Due to a bug, it was previously not possible to use the debugger on flakes with repl-overlays, or with pure evaluation in general:
-
-```
-$ nix repl --pure-eval
-Lix 2.94.0-dev-pre20250617-87d99da
-Type :? for help.
-Loading 'repl-overlays'...
-error: access to absolute path '/Users/jade/.config/nix/repl.nix' is forbidden in pure eval mode (use '--impure' to override)
-```
-
-This is now fixed.
-The contents of the repl-overlays file itself (i.e. most typically the top level lambda in it) will be evaluated in impure mode.
-It may be necessary to use `builtins.seq` to force the impure operations to happen first if one wants to do impure operations inside a repl-overlays file in pure evaluation mode.
@@ -1,32 +0,0 @@
---
-synopsis: Symbols reuses once-allocated Value to reduce garbage collected allocations
-issues: []
-cls: [3308, 3300, 3314, 3310, 3312, 3313]
-category: Improvements
-credits: [raito, horrors, thubrecht, nan-git]
---
-
-In the Lix evaluator, **symbols** represent immutable strings, like those used
-for attribute names.
-
-In evaluator design, such strings are typically [**interned**](https://en.wikipedia.org/wiki/String_interning), stored uniquely
-to save memory, and Lix inherits this approach from the original C++ codebase.
-
-However, some builtins, like `builtins.attrNames`, must return a `Value` type
-that can represent any Nix value (strings, integers, lists, etc.).
-
-Before this change, these builtins would create lists of `Value` objects by
-allocating them through the garbage collector, copying the symbol’s string
-content each time.
-
-This allocation is unnecessary if the interned symbols themselves also hold a
-`Value` representation allocated outside the garbage collector, since these
-live for the full duration of evaluation.
-
-As a result, this reduces the number of allocations, leading to:
-
-* A significant drop in maximum [resident set memory](https://en.wikipedia.org/wiki/Resident_set_size) (RSS), with some large-scale
-  tests showing up to 11% (about 500 MiB) savings in large colmena deployments.
-* A slight decrease in CPU usage during Nix evaluations.
-
-This change is inspired by https://github.com/NixOS/nix/pull/13258 but the approach is different.
@@ -1,15 +0,0 @@
---
-synopsis: uid-range depends on cgroups
-issues: []
-cls: [3230]
-category: "Breaking Changes"
-credits: [raito, horrors]
---
-
-`uid-range` builds now depends on `cgroups`, an experimental feature.
-
-`uid-range` builds already depended upon `auto-allocate-uids`, another experimental feature.
-
-The rationale for doing so is that `uid-range` provides a sandbox with many
-UIDs, this is useful for re-mapping them into a nested namespace, e.g. a
-container.
@@ -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)
@@ -191,15 +192,11 @@
  - [Hacking](contributing/hacking.md)
  - [Testing](contributing/testing.md)
  - [Experimental Features](contributing/experimental-features.md)
-  - [Deprecated Features](contributing/deprecated-features.md)
  - [CLI guideline](contributing/cli-guideline.md)
  - [C++ style guide](contributing/cxx.md)
 - [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)
+  <!-- RELENG-AUTO-INSERTION-MARKER (see releng/release_notes.py) -->
  - [Lix 2.90 (2024-07-10)](release-notes/rl-2.90.md)
  - [Nix 2.18 (2023-09-20)](release-notes/rl-2.18.md)
  - [Nix 2.17 (2023-07-24)](release-notes/rl-2.17.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`.

@@ -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         |
 |          |                   |                   |            |
@@ -34,15 +34,9 @@ keep-outputs = true       # Nice for developers
 keep-derivations = true   # Idem
 ```

-Other files can be included with a line like `include <path>`.
+Other files can be included with a line like `include <path>`, where `<path>` is interpreted relative to the current configuration file.
 A missing file is an error unless `!include` is used instead.

-Paths in `include`s and option values are interpreted relative to the current configuration file.
-In user configuration files, paths starting with `~/` are tilde expanded (by replacing the tilde by the value of `$HOME`).
-
-Only user configuration files (like `$XDG_CONFIG_HOME/nix/nix.conf` or the files listed in `$NIX_USER_CONF_FILES`) can use tilde paths relative to your home directory.
-Configuration listed in the `$NIX_CONFIG` environment variable may not use relative paths.
-
 A configuration setting usually overrides any previous value.
 However, for settings that take a list of items, you can prefix the name of the setting by `extra-` to *append* to the previous value.

@@ -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.
@@ -1,3 +1,23 @@
+xp_features_json = custom_target(
+  command : [nix, '__dump-xp-features'],
+  capture : true,
+  output : 'xp-features.json',
+)
+
+experimental_features_shortlist_md = custom_target(
+  command : nix_eval_for_docs + [
+    '--expr',
+    'import @INPUT0@ (builtins.fromJSON (builtins.readFile @INPUT1@))',
+  ],
+  input : [
+    '../../generate-xp-features-shortlist.nix',
+    xp_features_json,
+  ],
+  capture : true,
+  output : 'experimental-features-shortlist.md',
+  env : nix_env_for_docs,
+)
+
 # Intermediate step for manpage generation.
 # This splorks the output of generate-manpage.nix as JSON,
 # which gets written as a directory tree below.
@@ -31,23 +51,16 @@ nix3_cli_files = custom_target(

 conf_file_md = custom_target(
  command : [
-    python.full_path(),
-    '@SOURCE_ROOT@/lix/code-generation/build_settings.py',
-    '--kernel', host_machine.system(),
-    '--docs', '@OUTPUT@',
-    '--experimental-features', '@SOURCE_ROOT@/lix/libutil/experimental-features',
-    '@INPUT@',
+    nix_eval_for_docs,
+    '--expr',
+    '(import @INPUT0@).showSettings { inlineHTML = true; } (builtins.fromJSON (builtins.readFile @INPUT1@))',
  ],
+  capture : true,
  input : [
-    libexpr_setting_definitions,
-    libfetchers_setting_definitions,
-    file_transfer_setting_definitions,
-    libstore_setting_definitions,
-    archive_setting_definitions,
-    feature_setting_definitions,
-    logging_setting_definitions,
-    daemon_setting_definitions,
-    develop_settings_definitions,
+    '../../utils.nix',
+    conf_file_json,
+    experimental_features_shortlist_md,
  ],
  output : 'conf-file.md',
+  env : nix_env_for_docs,
 )
@@ -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
@@ -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**
 >
@@ -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 -->
@@ -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`]
@@ -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.

@@ -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.
@@ -148,8 +142,8 @@ To copy the store path with symbolic name `gcc` from another profile:
 $ nix-env --install --from-profile /nix/var/nix/profiles/foo gcc
 ```

-To install a specific [store derivation](@docroot@/glossary.md#gloss-store-derivation)
-(typically created by `nix-instantiate`):
+To install a specific [store derivation] (typically created by
+`nix-instantiate`):

 ```console
 $ nix-env --install /nix/store/fibjb1bfbpm5mrsxc4mh2d8n37sxh91i-gcc-3.4.3.drv
@@ -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
@@ -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.

@@ -5,13 +5,13 @@
 # Synopsis

 `nix-instantiate`
-  [`--parse` | `--eval` [`--strict`] [`--raw`] [`--json`] [`--xml`] ]
+  [`--parse` | `--eval` [`--strict`] [`--json`] [`--xml`] ]
  [`--read-write-mode`]
  [`--arg` *name* *value*]
  [{`--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
@@ -107,11 +97,6 @@ See that section for complete details (`nix-build --help`), but in summary, a pa
    > This option can cause non-termination, because lazy data
    > structures can be infinitely large.

-  - `--raw`
-    When used with `--eval`, the result must be coercible to a string, i.e.,
-    something that can be converted using `${...}`. The output is
-    printed exactly as-is, with no quotes, escaping, or trailing newline.
-
  - `--json`\
    When used with `--eval`, print the resulting value as an JSON
    representation of the abstract syntax tree rather than as a Nix expression.
@@ -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
@@ -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}}
@@ -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
@@ -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.
@@ -78,16 +78,6 @@ Most commands in Lix accept the following command-line options:

    Display the raw logs, with the progress bar at the bottom.

-  - `multiline`
-
-    Display a progress bar during the builds and in the lines below that one line per activity.
-
-
-  - `multiline-with-logs`
-
-    Display 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`

  By default, output written by builders to standard output and standard error is echoed to the Lix command's standard error.
@@ -1,37 +0,0 @@
-This section describes the notion of *deprecated features*, and how it fits into the big picture of the development of Lix.
-
-# What are deprecated features?
-
-Deprecated features are disabled by default, with the intent to eventually remove them.
-Users must explicitly enable them to keep using them, by toggling the associated [deprecated feature flags](@docroot@/command-ref/conf-file.md#conf-deprecated-features).
-This allows backwards compatibility and a graceful transition away from undesired features.
-
-# Which features can be deprecated?
-
-Undesired features should be soft-deprecated by yielding a warning when used for a significant amount of time before the can be deprecated.
-Legacy obsolete feature with little to no usage may go through this process faster.
-Deprecated features should have a migration path to a preferred alternative.
-
-# Lifecycle of a deprecated feature
-
-This description is not normative, but a feature removal may roughly happen like this:
-
-1. Add a warning when the feature is being used.
-2. Disable the feature by default, putting it behind a deprecated feature flag.
-  - If disabling the feature started out as an opt-in experimental feature, turn that experimental flag into a no-op or remove it entirely.
-    For example, `--extra-experimental-features=no-url-literals` becomes `--extra-deprecated-features=url-literals`.
-3. Decide on a time frame for how long that feature will still be supported for backwards compatibility, and clearly communicate that in the error messages.
-  - Sometimes, automatic migration to alternatives is possible, and such should be provided if possible
-  - At least one NixOS release cycle should be the minimum
-4. Finally remove the feature entirely, only keeping the error message for those still using it.
-
-# Relation to language versioning
-
-Obviously, removing anything breaks backwards compatibility.
-In an ideal world, we'd have SemVer controls over the language and its features, cleanly allowing us to make breaking changes.
-See https://wiki.lix.systems/books/lix-contributors/page/language-versioning and [RFC 137](https://github.com/nixos/rfcs/pull/137) for efforts on that.
-However, we do not live in such an ideal world, and currently this goal is so far away, that "just disable it with some back-compat for a couple of years" is the most realistic solution, especially for comparatively minor changes.
-
-# Currently available deprecated features
-
-{{#include @generated@/../../../lix/libutil/deprecated-feature-descriptions.md}}
@@ -99,4 +99,4 @@ This means that experimental features and RFCs are orthogonal mechanisms, and ca

 # Currently available experimental features

-{{#include @generated@/../../../lix/libutil/experimental-feature-descriptions.md}}
+{{#include @generated@/contributing/experimental-feature-descriptions.md}}
@@ -39,30 +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:
+As always you may run [stdenv's phases by name](https://nixos.org/manual/nixpkgs/unstable/#sec-building-stdenv-package-in-nix-shell), e.g.:

 ```bash
-$ just setup build test-unit
-$ just install test-integration
+$ configurePhase
+$ buildPhase
+$ checkPhase
+$ installPhase
+$ installCheckPhase
 ```

-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.
-
-You can also build Lix manually:
+To build manually, however, use the following:

 ```bash
 $ meson setup ./build "--prefix=$out" $mesonFlags
@@ -77,7 +64,9 @@ $ meson install -C build
 $ meson test -C build --suite=installcheck
 ```

-In both cases, Lix will be installed to `$PWD/outputs`, the `/bin` of which is prepended to PATH in the development shells.
+(Check and installcheck may both be done after install, allowing you to omit the --suite argument entirely, but this is the order package.nix runs them in.)
+
+This will install Lix to `$PWD/outputs`, the `/bin` of which is prepended to PATH in the development shells.

 If the tests fail and Meson helpfully has no output for why, use the `--print-error-logs` option to `meson test`.

@@ -113,14 +102,14 @@ $ meson compile -C build nixexpr
 All targets may be addressed as their output, relative to the build directory, e.g.:

 ```bash
-$ meson compile -C build lix/libexpr/liblixexpr.so
+$ meson compile -C build src/libexpr/liblixexpr.so
 ```

 But Meson does not consider intermediate files like object files targets.
 To build a specific object file, use Ninja directly and specify the output file relative to the build directory:

 ```bash
-$ ninja -C build lix/libexpr/liblixexpr.so.p/nixexpr.cc.o
+$ ninja -C build src/libexpr/liblixexpr.so.p/nixexpr.cc.o
 ```

 To inspect the canonical source of truth on what the state of the buildsystem configuration is, use:
@@ -152,7 +141,6 @@ Lix can be built for various platforms, as specified in [`flake.nix`]:

 - `x86_64-linux`
 - `x86_64-darwin`
- `x86_64-freebsd`
 - `i686-linux`
 - `aarch64-linux`
 - `aarch64-darwin`
@@ -180,27 +168,8 @@ or for Nix with the [`flakes`] and [`nix-command`] experimental features enabled
 $ nix build .#packages.aarch64-linux.default
 ```

-### Cross compiling using the Lix flake
-
-Lix can also be easily cross compiled to the following arbitrarily-chosen system doubles, which can be useful for bootstrapping Lix on new platforms.
-These are specified in `crossSystems` in `flake.nix`; feel free to submit changes to add new ones if they are useful to you.
-
- `armv6l-linux`
- `armv7l-linux`
- `aarch64-linux`
- `riscv64-linux`
-
-For example, to cross-compile Lix for `armv6l-linux` from another Linux, use the following:
-
-```console
-$ nix build .#nix-armv6l-linux
-```
-
-It's also possible to cross-compile a tarball of binaries suitable for the Lix installer, for example, for `riscv64-linux`:
-
-```console
-$ nix build .#nix-riscv64-linux.passthru.binaryTarball
-```
+Cross-compiled builds are available for ARMv6 (`armv6l-linux`) and ARMv7 (`armv7l-linux`).
+Add more [system types](#system-type) to `crossSystems` in `flake.nix` to bootstrap Nix on unsupported platforms.

 ### Building for multiple platforms at once

@@ -229,7 +198,7 @@ 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 +225,13 @@ 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`.

@@ -313,8 +282,9 @@ Regular markdown files used for the manual have a base path of their own and the

 ## API documentation

-Doxygen API documentation will be available online in the future ([tracking issue](https://git.lix.systems/lix-project/lix/issues/422)).
-You can also build and view it yourself:
+Doxygen API documentation is [available
+online](https://hydra.nixos.org/job/nix/master/internal-api-docs/latest/download-by-type/doc/internal-api-docs). You
+can also build and view it yourself:

 ```console
 # nix build .#hydraJobs.internal-api-docs
@@ -324,50 +294,44 @@ You can also build and view it yourself:
 or inside a `nix develop` shell by running:

 ```bash
-$ meson configure build -Dinternal-api-docs=enabled
 $ meson compile -C build internal-api-docs
 $ xdg-open ./outputs/doc/share/doc/nix/internal-api/html/index.html
 ```

 ## Coverage analysis

-A coverage analysis report will be available online in the future (FIXME(lix-hydra)).
-You can build it yourself:
+A coverage analysis report is [available
+online](https://hydra.nixos.org/job/nix/master/coverage/latest/download-by-type/report/coverage). You
+can build it yourself:

 ```
 # nix build .#hydraJobs.coverage
 # xdg-open ./result/coverage/index.html
 ```

-Metrics about the change in line/function coverage over time will be available in the future (FIXME(lix-hydra)).
+Metrics about the change in line/function coverage over time are also
+[available](https://hydra.nixos.org/job/nix/master/coverage#tabs-charts).

 ## Add a release note

 `doc/manual/rl-next` contains release notes entries for all unreleased changes.

 User-visible changes should come with a release note.
-Developer-facing changes should have a release note in the Development category if they are significant and if developers should know about them.

 ### Add an entry

-Here's what a complete entry looks like.
-The file name is not incorporated in the final document, and is generally a super brief summary of the change synopsis.
+Here's what a complete entry looks like. The file name is not incorporated in the document.

-```markdown
+```
 ---
 synopsis: Basically a title
 # 1234 or gh#1234 will refer to CppNix GitHub, fj#1234 will refer to a Lix forgejo issue.
 issues: [1234, fj#1234]
-# Use this *only* if there is a CppNix pull request associated with this change.
+# Use this *only* if there is a CppNix pull request associated with this change
 prs: 1238
-# List of Lix Gerrit changelist numbers.
-# If there is an associated Lix GitHub PR, just put in the Gerrit CL number.
+# List of Lix Gerrit changelist numbers; if there is an associated Lix GitHub
+# PR, just put in the Gerrit CL number.
 cls: [123]
-# Heading that this release note will appear under.
-category: Breaking Changes
-# Add a credit mention in the bottom of the release note.
-# your-name is used as a key into doc/manual/change-authors.yml for metadata
-credits: [your-name]
 ---

 Here's one or more paragraphs that describe the change.
@@ -382,105 +346,7 @@ Significant changes should add the following header, which moves them to the top
 significance: significant
 ```

-The following categories of release notes are supported (see `maintainers/build-release-notes.py`):
- Breaking Changes
- Features
- Improvements
- Fixes
- Packaging
- Development
- Miscellany
-
-The `credits` field, if present, gives credit to the author of the patch in the release notes with a message like "Many thanks to (your-name) for this" and linking to GitHub or Forgejo profiles if listed.
-
-If you are forward-porting a change from CppNix, please credit the original author, and optionally credit yourself.
-When adding credits metadata for people external to the project and deciding whether to put in a `display_name`, consider what they are generally known as in the community; even if you know their full name (e.g. from their GitHub profile), we suggest only adding it as a display name if that is what they go by in the community.
-There are multiple reasons we follow this practice, but it boils down to privacy and consent: we would rather not capture full names that are not widely used in the community without the consent of the parties involved, even if they are publicly available.
-As of this writing, the entries with full names as `display_name` are either members of the CppNix team or people who added them themselves.
-
-The names specified in `credits` are used as keys to look up the authorship info in `doc/manual/change-authors.yml`.
-The only mandatory part is that every key appearing in `credits` has an entry present in `change-authors.yml`.
-All of the following properties are optional; you can specify `{}` as the metadata if you want a simple non-hyperlinked mention.
-The following properties are supported:
-
- `display_name`: display name used in place of the key when showing names, if present.
- `forgejo`: Forgejo username. The name in the release notes will be a link to this, if present.
- `github`: GitHub username, used if `forgejo` is not set, again making a link.
-
 ### Build process

 Releases have a precomputed `rl-MAJOR.MINOR.md`, and no `rl-next.md`.
 Set `buildUnreleasedNotes = true;` in `flake.nix` to build the release notes on the fly.
-
-## Adding experimental or deprecated features, global settings, or builtins
-
-Experimental and deprecated features, global settings, and builtins are generally referenced both in the code and in the documentation.
-To prevent duplication or divergence, they are defined in data files, and a script generates the necessary glue.
-The data file format is similar to the release notes: it consists of a YAML metadata header, followed by the documentation in Markdown format.
-
-### Experimental or deprecated features
-
-Experimental and deprecated features support the following metadata properties:
-* `name` (required): user-facing name of the feature, to be used in `nix.conf` options and on the command line.
-  This should also be the stem of the file name (with extension `md`).
-* `internalName` (required): identifier used to refer to the feature inside the C++ code.
-
-Experimental feature data files should live in `lix/libutil/experimental-features`, and deprecated features in `lix/libutil/deprecated-features`.
-They must be listed in the `experimental_feature_definitions` or `deprecated_feature_definitions` lists in `lix/libutil/meson.build` respectively to be considered by the build system.
-
-### Global settings
-
-Global settings support the following metadata properties:
-* `name` (required): user-facing name of the setting, to be used as key in `nix.conf` and in the `--option` command line argument.
-* `internalName` (required): identifier used to refer to the setting inside the C++ code.
-* `platforms` (optional): a list specifying the platforms on which this setting is available.
-  If not specified, it is available on all platforms.
-  Valid platform names are `darwin`, `linux`.
-* `type` (optional): C++ type of the setting value.
-  This specifies the setting object type as `Setting<T>`; if more control is required, use `settingType` instead.
-* `settingType` (required if `type` is not specified): C++ type of the setting object.
-* `default` (optional): default value of the setting.
-  `null`, truth values, integers, strings and lists are supported as long as the correct YAML type is used, `type` is not taken into account).
-  Other types, machine-dependent values or non-standard representations must be handled using `defaultExpr` and `defaultText` instead.
-* `defaultExpr` (required if `default` is not specified): a string containing the C++ expression representing the default value.
-* `defaultText` (required if `default` is not specified): a string containing the Markdown expression representing the default value in the documentation.
-  Literal values are conventionally surrounded by backticks, and a system-dependent value is signaled by `*machine-specific*`.
-* `aliases` (optional): a list of secondary user-facing names under which the setting is available.
-  Defaults to empty if not specified.
-* `experimentalFeature` (optional): the user-facing name of the experimental feature which needs to be enabled to change the setting.
-  If not specified, no experimental feature is required.
-* `deprecated` (optional): whether the setting is deprecated and shown as such in the documentation for `nix.conf`.
-  Defaults to false if not specified.
-
-Settings are not collected in a single place in the source tree, so an appropriate place needs to be found for the setting to live.
-Look for related setting definition files under second-level subdirectories of `lix` whose name includes `settings`.
-Then add the new file there, and don't forget to register it in the appropriate `meson.build` file.
-
-### Builtin functions
-
-The following metadata properties are supported for builtin functions:
-* `name` (required): the language-facing name (as a member of the `builtins` attribute set) of the function.
-* `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.
-  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.
-  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`.
-
-### Builtin constants
-The following metadata properties are supported for builtin constants:
-* `name` (required): the language-facing name (as a member of the `builtins` attribute set) of the constant.
-* `type` (required): the Nix language type of the constant; the C++ type is automatically derived.
-* `constructorArgs` (optional): list of strings containing C++ expressions passed as arguments to the appropriate `Value` constructor.
-  If the value computation is more complex, `implementation` can be used instead.
-* `implementation` (required if `constructorArgs` is not specified): string containing a C++ expressing computing the value of the constant.
-* `impure` (optional): whether the constant is considered impure.
-  Impure constants are not available when pure evaluation mode is activated.
-  Defaults to `false` when not specified.
-
-New builtin constant definition files must be added to `lix/libexpr/builtin-constants` and registered in the `builtin_constant_definitions` list in `lix/libexpr/meson.build`.
@@ -0,0 +1,15 @@
+# Intermediate step for experimental-feature-descriptions.md.
+# This splorks the output of generate-xp-features.nix as JSON,
+# which gets written as a directory tree below.
+experimental_feature_descriptions_md = custom_target(
+  command : nix_eval_for_docs + [
+    '--expr',
+    'import @INPUT0@ (builtins.fromJSON (builtins.readFile @INPUT1@))',
+  ],
+  input : [
+    '../../generate-xp-features.nix',
+    xp_features_json,
+  ],
+  capture : true,
+  output : 'experimental-feature-descriptions.md',
+)
@@ -13,7 +13,7 @@ The unit tests are defined using the [googletest] and [rapidcheck] frameworks.
 >
 > ```
 > …
-> ├── lix
+> ├── src
 > │   ├── libexpr
 > │   │   ├── …
 > │   │   ├── value
@@ -46,10 +46,10 @@ The unit tests are defined using the [googletest] and [rapidcheck] frameworks.
 > …       …   …   …   …   …
 > ```

-The unit tests for each Lix library (`liblixexpr`, `liblixstore`, etc..) live inside a directory `lix/${library_shortname}/tests` within the directory for the library (`lix/${library_shortname}`).
+The unit tests for each Lix library (`liblixexpr`, `liblixstore`, etc..) live inside a directory `src/${library_shortname}/tests` within the directory for the library (`src/${library_shortname}`).

 The data is in `tests/unit/LIBNAME/data/LIBNAME`, with one subdir per library, with the same name as where the code goes.
-For example, `liblixstore` code is in `lix/libstore`, and its test data is in `tests/unit/libstore/data/libstore`.
+For example, `liblixstore` code is in `src/libstore`, and its test data is in `tests/unit/libstore/data/libstore`.
 The path to the unit test data directory is passed to the unit test executable with the environment variable `_NIX_TEST_UNIT_DATA`.

 ### Running tests
@@ -247,6 +247,7 @@ To ensure that characterization testing doesn't make it harder to intentionally

 The integration tests are defined in the Nix flake under the `hydraJobs.tests` attribute.
 These tests include everything that needs to interact with external services or run Lix in a non-trivial distributed setup.
+Because these tests are expensive and require more than what the standard github-actions setup provides, they only run on the master branch (on <https://hydra.nixos.org/jobset/nix/master>).

 You can run them manually with `nix build .#hydraJobs.tests.{testName}` or `nix-build -A hydraJobs.tests.{testName}`

@@ -345,7 +346,7 @@ rg '(?:[^A-Za-z]|^)(_[A-Z][^-\[ }/:");$(]+)' -r '$1' --no-filename --only-matchi
 rg '\$\{?([A-Z][^-\[ }/:");]+)' -r '$1' --no-filename --only-matching tests | sort -u > vars.txt
 ```

-I grepped `lix/` for `get[eE]nv\("` to find the mentions in Lix code.
+I grepped `src/` for `get[eE]nv\("` to find the mentions in Lix code.

 ### Used by Lix testing support code

@@ -361,8 +362,8 @@ I grepped `lix/` for `get[eE]nv\("` to find the mentions in Lix code.

 - `_NIX_FORCE_HTTP` - Forces file URIs to be treated as remote ones.

-  Used by `lix/libfetchers/git.cc`, `lix/libstore/http-binary-cache-store.cc`,
-  `lix/libstore/local-binary-cache-store.cc`. Seems to be for forcing Git
+  Used by `src/libfetchers/git.cc`, `src/libstore/http-binary-cache-store.cc`,
+  `src/libstore/local-binary-cache-store.cc`. Seems to be for forcing Git
  clones of `git+file://` URLs, making the HTTP binary
  cache store accept `file://` URLs (presumably passing them to curl?), and
  unknown reasons for the local binary cache.
@@ -374,7 +375,7 @@ I grepped `lix/` for `get[eE]nv\("` to find the mentions in Lix code.
  `structuredAttrs` documentation.
 - `NIX_BIN_DIR`, `NIX_STORE_DIR` (or its inconsistently-used old alias `NIX_STORE`), `NIX_DATA_DIR`,
  `NIX_LOG_DIR`, `NIX_LOG_DIR`, `NIX_STATE_DIR`, `NIX_CONF_DIR` -
-  Overrides compile-time configuration of various locations used by Lix. See `lix/libstore/globals.cc`.
+  Overrides compile-time configuration of various locations used by Lix. See `src/libstore/globals.cc`.

  **Expected value**: a directory
 - `NIX_DAEMON_SOCKET_PATH` (optional) - Overrides the daemon socket path from `$NIX_STATE_DIR/daemon-socket/socket`.
@@ -427,12 +428,14 @@ I grepped `lix/` for `get[eE]nv\("` to find the mentions in Lix code.
 - `NIX_SHOW_STATS_PATH` - Writes those statistics into a file at the given path instead of stdout. Undocumented.
 - `NIX_SHOW_SYMBOLS` - Dumps the symbol table into the show-stats json output.
 - `TERM` - If `dumb` or unset, disables ANSI colour output.
- `FORCE_COLOR`, `CLICOLOR_FORCE` - Enables ANSI colour output if `NO_COLOR`/`NOCOLOR` not set.
 - `NO_COLOR`, `NOCOLOR` - Disables ANSI colour output.
 - `_NIX_DEVELOPER_SHOW_UNKNOWN_LOCATIONS` - Highlights unknown locations in errors.
 - `NIX_PROFILE` - Selects which profile `nix-env` will operate on. Documented elsewhere.
 - `NIX_SSHOPTS` - Options passed to `ssh(1)` when using a ssh remote store.
  Incorrectly documented on `nix-copy-closure` which is *surely* not the only place they are used??
+- `_NIX_TEST_NO_LSOF` - Used on non-Linux, non-macOS platforms to disable using `lsof` when finding gc roots.
+
+  Since https://git.lix.systems/lix-project/lix/issues/156 was fixed, this should probably just be removed as it was a bad workaround for a macOS issue.
 - `_NIX_TEST_GC_SYNC_1` - Path to a pipe that is used to block the GC briefly to validate invariants from the test suite.
 - `_NIX_TEST_GC_SYNC_2` - Path to a pipe that is used to block the GC briefly to validate invariants from the test suite.
 - `_NIX_TEST_FREE_SPACE_FILE` - Path to a file containing a decimal number with the free space that the GC is to believe it has.
@@ -449,6 +452,9 @@ 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`.
@@ -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.

@@ -1,6 +1,6 @@
 # Installing a Binary Distribution

-See <https://lix.systems/install/> for more details.
+See https://lix.systems/install/ for more details.

 <!--

@@ -36,10 +36,7 @@ All users of the Lix daemon may do the following to bring things into the Nix st
    - Input-addressed, so they are run in the sandbox with no network access, with the following exceptions:

      - The (poorly named, since it is not *just* about chroot) property `__noChroot` is set on the derivation and `sandbox` is set to `relaxed`.
-      - On macOS, the derivation property `__darwinAllowLocalNetworking` allows network access to localhost from input-addressed derivations regardless of the `sandbox` setting value.
-        This property exists with such semantics because macOS has no network namespace equivalent to isolate individual processes' localhost networking.
-      - On macOS, the derivation property `__sandboxProfile` accepts extra sandbox profile S-expressions, allowing derivations to bypass arbitrary parts of the sandbox without altogether disabling it.
-        This is only permitted when `sandbox` is set to `relaxed`.
+      - On macOS, the derivation property `__darwinAllowLocalNetworking` allows network access to localhost from input-addressed derivations regardless of the `sandbox` setting value. This property exists with such semantics because macOS has no network namespace equivalent to isolate individual processes' localhost networking.
    - Output-addressed, so they are run with network access but their result must match an expected hash.

  Trusted users may set any setting, including `sandbox = false`, so the sandbox state can be different at runtime from what is described in `nix.conf` for builds invoked with such settings.
@@ -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
@@ -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**
@@ -285,12 +292,6 @@ Derivations can declare some infrequently used optional attributes.
    (associative) arrays. For example, the attribute `hardening.format = true`
    ends up as the Bash associative array element `${hardening[format]}`.

-    > **Warning**
-    >
-    > If set to `true`, other advanced attributes such as [`allowedReferences`](#adv-attr-allowedReferences), [`allowedReferences`](#adv-attr-allowedReferences), [`allowedRequisites`](#adv-attr-allowedRequisites),
-    [`disallowedReferences`](#adv-attr-disallowedReferences) and [`disallowedRequisites`](#adv-attr-disallowedRequisites), maxSize, and maxClosureSize.
-    will have no effect.
-
  - [`outputChecks`]{#adv-attr-outputChecks}\
    When using [structured attributes](#adv-attr-structuredAttrs), the `outputChecks`
    attribute allows defining checks per-output.
@@ -325,6 +326,7 @@ Derivations can declare some infrequently used optional attributes.
    ```

  - [`unsafeDiscardReferences`]{#adv-attr-unsafeDiscardReferences}\
+
    When using [structured attributes](#adv-attr-structuredAttrs), the
    attribute `unsafeDiscardReferences` is an attribute set with a boolean value for each output name.
    If set to `true`, it disables scanning the output for runtime dependencies.
@@ -4,7 +4,7 @@ These constants are built into the Nix language evaluator:

 <dl>

-{{#include @generated@/../../../lix/libexpr/builtin-constants.md}}
+{{#include @generated@/language/builtin-constants.md}}

 </dl>

@@ -15,6 +15,6 @@ For convenience, some built-ins can be accessed directly:
  <dd><p><var>derivation</var> is described in
         <a href="derivations.md">its own section</a>.</p></dd>

-{{#include @generated@/../../../lix/libexpr/builtins.md}}
+{{#include @generated@/language/builtins.md}}

 </dl>
@@ -0,0 +1,27 @@
+builtins_md = custom_target(
+  command : nix_eval_for_docs + [
+    '--expr',
+    'import @INPUT0@ (builtins.fromJSON (builtins.readFile @INPUT1@)).builtins',
+  ],
+  capture : true,
+  input : [
+    '../../generate-builtins.nix',
+    language_json,
+  ],
+  output : 'builtins.md',
+  env : nix_env_for_docs,
+)
+
+builtin_constants_md = custom_target(
+  command : nix_eval_for_docs + [
+    '--expr',
+    'import @INPUT0@ (builtins.fromJSON (builtins.readFile @INPUT1@)).constants',
+  ],
+  capture : true,
+  input : [
+    '../../generate-builtin-constants.nix',
+    language_json,
+  ],
+  output : 'builtin-constants.md',
+  env : nix_env_for_docs,
+)
@@ -26,8 +26,6 @@
 | Logical conjunction (`AND`)            | *bool* `&&` *bool*                         | left          | 12         |
 | Logical disjunction (`OR`)             | *bool* <code>\|\|</code> *bool*            | left          | 13         |
 | [Logical implication]                  | *bool* `->` *bool*                         | none          | 14         |
-| \[Experimental\] [Function piping]     | *expr* `\|>` *func*                        | left          | 15         |
-| \[Experimental\] [Function piping]     | *expr* `<\|` *func*                        | right         | 16         |

 [string]: ./values.md#type-string
 [path]: ./values.md#type-path
@@ -61,10 +59,8 @@ The result is a [Boolean] value.

 ## Arithmetic

-Numbers will retain their type unless mixed with other numeric types:
-Pure integer operations will always return integers, whereas any operation involving at least one floating point number returns a floating point number.
-
-Integer overflow (of 64-bit signed integers) and division by zero are defined to throw an error.
+Numbers are type-compatible:
+Pure integer operations will always return integers, whereas any operation involving at least one floating point number return a floating point number.

 See also [Comparison] and [Equality].

@@ -147,103 +143,21 @@ All comparison operators are implemented in terms of `<`, and the following equi
 | *a* `>`  *b* |       *b* `<` *a*     |
 | *a* `>=` *b* | `! (` *a* `<` *b* `)` |

-Note that the above behaviour violates IEEE 754 for floating point numbers with respect to NaN, for instance.
-This may be fixed in a future major language revision.
-
 [Comparison]: #comparison-operators

 ## Equality

-The following equality comparison rules are followed in order:
-
- Comparisons are first, sometimes, performed by identity (pointer value), and whether or not this occurs varies depending on the context in which the comparison is performed; for example, through `builtins.elem`, comparison of lists, or other cases.
-  The exact instances in which this occurs, aside from direct list and attribute set comparisons as discussed below, are too dependent on implementation details to meaningfully document.
-
-  See [note on identity comparison](#identity-comparison) below.
- Comparisons between a combination of integers and floating point numbers are first converted to floating point then compared as floating point.
- Comparisons between values of differing types, besides the ones mentioned in the above rule, are unequal.
- Strings are compared as their string values, disregarding string contexts.
- Paths are compared as their absolute form (since they are stored as such).
- [Functions][function] are always considered unequal, including with themselves.
- The following are compared in the typical manner:
-  - Integers
-  - Floating point numbers have equality comparison per IEEE 754.
-
-    Note that this means that just like in most languages, floating point arithmetic results are not typically equality comparable, and should instead be compared by checking that the absolute difference is less than some error margin.
-  - Booleans
-  - Null
- [Attribute sets][attribute set] are compared following these rules in order:
-  - If both attribute sets have the same identity (via pointer equality), they are considered equal, regardless of whether the contents have reflexive equality (e.g. even if there are functions contained within).
-
-    See [note on identity comparison](#identity-comparison) below.
-  - If both attribute sets have `type = "derivation"` and have an attribute `outPath` that is equal, they are considered equal.
-
-    This means that two results of `builtins.derivation`, regardless of other things added to their attributes via `//` afterwards (or `passthru` in nixpkgs), will compare equal if they passed the same arguments to `builtins.derivation`.
-  - Otherwise, they are compared element-wise in an unspecified order.
-    Although this order *may* be deterministic in some cases, this is not guaranteed, and correct code must not rely on this ordering behaviour.
-
-    The order determines which elements are evaluated first and thus, if there are throwing values in the attribute set, which of those get evaluated, if any, before the comparison returns an unequal result.
- Lists are compared following these rules in order:
-  - If both lists have the same identity (via pointer equality), they are considered equal, regardless of whether the contents have reflexive equality (e.g. even if there are functions contained within).
-
-    See [note on identity comparison](#identity-comparison) below.
-  - Otherwise, they are compared element-wise in list order.
+- [Attribute sets][attribute set] and [list]s are compared recursively, and therefore are fully evaluated.
+- Comparison of [function]s always returns `false`.
+- Numbers are type-compatible, see [arithmetic] operators.
+- Floating point numbers only differ up to a limited precision.

 [function]: ./constructs.md#functions

 [Equality]: #equality

-### Identity comparison
-
-In the current revision of the Nix language, values are first compared by identity (pointer equality).
-This means that values that are not reflexively equal (that is, they do not satisfy `a == a`), such as functions, are nonetheless sometimes compared as equal with themselves if they are placed in attribute sets or lists, or are compared through other indirect means.
-
-Whether identity comparison applies to a given usage of the language aside from direct list and attribute set comparison is strongly dependent on implementation details to the point it is not feasible to document the exact instances.
-
-This is rather unfortunate behaviour which is regrettably load-bearing on nixpkgs (such as with the `type` attribute of NixOS options) and cannot be changed for the time being.
-It may be changed in a future major language revision.
-
-Correct code must not rely on this behaviour.
-
-For example:
-
-```
-nix-repl> let f = x: 1; s = { func = f; }; in [ (f == f) (s == s) ]
-[ false true ]
-```
-
 ## Logical implication

 Equivalent to `!`*b1* `||` *b2*.

 [Logical implication]: #logical-implication
-
-## \[Experimental\] Function piping
-
-*This language feature is still experimental and may change at any time. Enable `--extra-experimental-features pipe-operator` to use it.*
-
-Pipes are a dedicated operator for function application, but with reverse order and a lower binding strength.
-This allows you to chain function calls together in way that is more natural to read and requires less parentheses.
-
-`a |> f b |> g` is equivalent to `g (f b a)`.
-`g <| f b <| a` is equivalent to `g (f b a)`.
-
-Example code snippet:
-
-```nix
-defaultPrefsFile = defaultPrefs
-  |> lib.mapAttrsToList (
-    key: value: ''
-      // ${value.reason}
-      pref("${key}", ${builtins.toJSON value.value});
-    ''
-  )
-  |> lib.concatStringsSep "\n"
-  |> pkgs.writeText "nixos-default-prefs.js";
-```
-
-Note how `mapAttrsToList` is called with two arguments (the lambda and `defaultPrefs`),
-but moving the last argument in front of the rest improves the reading flow.
-This is common for functions with long first argument, including all `map`-like functions.
-
-[Function piping]: #experimental-function-piping
@@ -7,16 +7,13 @@
  *Strings* can be written in three ways.

  The most common way is to enclose the string between double quotes,
-  e.g., `"foo bar"`. Strings can span multiple lines. The backslash
-  (`\`) can be used to escape characters: newlines, carriage returns
-  and tabs may be written as `\n`, `\r` and `\t` respectively; any
-  other characters can be preceded by a backslash to remove any
-  special meaning they may have, like the special characters `"` and
-  `\` and the character sequence `${`.
+  e.g., `"foo bar"`. Strings can span multiple lines. The special
+  characters `"` and `\` and the character sequence `${` must be
+  escaped by prefixing them with a backslash (`\`). Newlines, carriage
+  returns and tabs can be written as `\n`, `\r` and `\t`,
+  respectively.

  You can include the results of other expressions into a string by enclosing them in `${ }`, a feature known as [string interpolation].
-  Due to a parser issue that has since come to be relied upon, the character sequence `$${` is interpreted literally and does not introduce an interpolation.
-  To express a `$` character immediately followed by an interpolation, the former must be escaped.

  [string interpolation]: ./string-interpolation.md

@@ -46,16 +43,16 @@
  Note that the whitespace and newline following the opening `''` is
  ignored if there is no non-whitespace text on the initial line.

+  Indented strings support [string interpolation].
+
  Since `${` and `''` have special meaning in indented strings, you
  need a way to quote them. `$` can be escaped by prefixing it with
  `''` (that is, two single quotes), i.e., `''$`. `''` can be escaped
-  by prefixing it with `'`, i.e., `'''`. Linefeed, carriage-return and tab
+  by prefixing it with `'`, i.e., `'''`. `$` removes any special
+  meaning from the following `$`. Linefeed, carriage-return and tab
  characters can be written as `''\n`, `''\r`, `''\t`, and `''\`
  escapes any other character.

-  Indented strings support [string interpolation] using `${ }` the same way regular strings do.
-  `$${` is interpreted literally in indented strings as well, so the `$` character must be escaped if it is to be followed by an interpolation.
-
  Indented strings are primarily useful in that they allow multi-line
  string literals to follow the indentation of the enclosing Nix
  expression, and that less escaping is typically necessary for
@@ -77,14 +74,17 @@
  }
  ```

+  Finally, as a convenience, *URIs* as defined in appendix B of
+  [RFC 2396](http://www.ietf.org/rfc/rfc2396.txt) can be written *as
+  is*, without quotes. For instance, the string
+  `"http://example.org/foo.tar.bz2"` can also be written as
+  `http://example.org/foo.tar.bz2`.
+
 - <a id="type-number" href="#type-number">Number</a>

  Numbers, which can be *integers* (like `123`) or *floating point*
  (like `123.43` or `.27e13`).

-  Integers in the Nix language are 64-bit signed integers.
-  Integer overflow is defined to throw an error.
-
  See [arithmetic] and [comparison] operators for semantics.

  [arithmetic]: ./operators.md#arithmetic
@@ -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* \
@@ -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**
 >
@@ -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.
@@ -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.
@@ -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.
@@ -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.

@@ -1,489 +0,0 @@
-# Lix 2.91 "Dragon's Breath" (2024-08-12)
-
-
-# Lix 2.91.0 (2024-08-12)
-
-## Breaking Changes
- Block io_uring in the Linux sandbox [cl/1611](https://gerrit.lix.systems/c/lix/+/1611)
-
-  The io\_uring API has the unfortunate property that it is not possible to selectively decide which operations should be allowed.
-  This, together with the fact that new operations are routinely added, makes it a hazard to the proper function of the sandbox.
-
-  Therefore, any access to io\_uring has been made unavailable inside the sandbox.
-  As such, attempts to execute any system calls forming part of this API will fail with the error `ENOSYS`, as if io\_uring support had not been configured into the kernel.
-
-  Many thanks to [alois31](https://git.lix.systems/alois31) for this.
- The `build-hook` setting is now deprecated
-
-  Build hooks communicate with the daemon using a custom, internal, undocumented protocol that is entirely unversioned and cannot be changed.
-  Since we intend to change it anyway we must unfortunately deprecate the current build hook infrastructure.
-  We do not expect this to impact most users—we have not found any uses of `build-hook` in the wild—but if this does affect you, we'd like to hear from you!
- Lix no longer speaks the Nix remote-build worker protocol to clients or servers older than CppNix 2.3 [fj#325](https://git.lix.systems/lix-project/lix/issues/325) [cl/1207](https://gerrit.lix.systems/c/lix/+/1207) [cl/1208](https://gerrit.lix.systems/c/lix/+/1208) [cl/1206](https://gerrit.lix.systems/c/lix/+/1206) [cl/1205](https://gerrit.lix.systems/c/lix/+/1205) [cl/1204](https://gerrit.lix.systems/c/lix/+/1204) [cl/1203](https://gerrit.lix.systems/c/lix/+/1203) [cl/1479](https://gerrit.lix.systems/c/lix/+/1479)
-
-  CppNix 2.3 was released in 2019, and is the new oldest supported version. We
-  will increase our support baseline in the future up to a final version of CppNix
-  2.18 (which may happen soon given that it is the only still-packaged and thus
-  still-tested >2.3 version), but this step already removes a significant amount
-  of dead, untested, code paths.
-
-  Lix speaks the same version of the protocol as CppNix 2.18 and that fact will
-  never change in the future; the Lix plans to replace the protocol for evolution
-  will entail a complete incompatible replacement that will be supported in
-  parallel with the old protocol. Lix will thus retain remote build compatibility
-  with CppNix as long as CppNix maintains protocol compatibility with 2.18, and
-  as long as Lix retains legacy protocol support (which will likely be a long
-  time given that we plan to convert it to a frozen-in-time shim).
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-## Features
- Pipe operator `|>` (experimental) [fj#438](https://git.lix.systems/lix-project/lix/issues/438) [cl/1654](https://gerrit.lix.systems/c/lix/+/1654)
-
-  Implementation of the pipe operator (`|>`) in the language as described in [RFC 148](https://github.com/NixOS/rfcs/pull/148).
-  The feature is still marked experimental, enable `--extra-experimental-features pipe-operator` to use it.
-
-  Many thanks to [piegames](https://git.lix.systems/piegames) and [eldritch horrors](https://git.lix.systems/pennae) for this.
-
-## Improvements
- Trace which part of a `foo.bar.baz` expression errors [cl/1505](https://gerrit.lix.systems/c/lix/+/1505) [cl/1506](https://gerrit.lix.systems/c/lix/+/1506)
-
-  Previously, if an attribute path selection expression like `linux_4_9.meta.description` it wouldn't show you which one of those parts in the attribute path, or even that that line of code is what caused evaluation of the failing expression.
-  The previous error looks like this:
-
-  ```
-  pkgs.linuxKernel.kernels.linux_4_9.meta.description
-
-  error:
-         … while evaluating the attribute 'linuxKernel.kernels.linux_4_9.meta.description'
-           at /nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source/pkgs/top-level/linux-kernels.nix:278:5:
-            277|   } // lib.optionalAttrs config.allowAliases {
-            278|     linux_4_9 = throw "linux 4.9 was removed because it will reach its end of life within 22.11";
-               |     ^
-            279|     linux_4_14 = throw "linux 4.14 was removed because it will reach its end of life within 23.11";
-
-         … while calling the 'throw' builtin
-           at /nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source/pkgs/top-level/linux-kernels.nix:278:17:
-            277|   } // lib.optionalAttrs config.allowAliases {
-            278|     linux_4_9 = throw "linux 4.9 was removed because it will reach its end of life within 22.11";
-               |                 ^
-            279|     linux_4_14 = throw "linux 4.14 was removed because it will reach its end of life within 23.11";
-
-         error: linux 4.9 was removed because it will reach its end of life within 22.11
-  ```
-
-  Now, the error will look like this:
-
-  ```
-  pkgs.linuxKernel.kernels.linux_4_9.meta.description
-
-  error:
-         … while evaluating the attribute 'linuxKernel.kernels.linux_4_9.meta.description'
-           at /nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source/pkgs/top-level/linux-kernels.nix:278:5:
-            277|   } // lib.optionalAttrs config.allowAliases {
-            278|     linux_4_9 = throw "linux 4.9 was removed because it will reach its end of life within 22.11";
-               |     ^
-            279|     linux_4_14 = throw "linux 4.14 was removed because it will reach its end of life within 23.11";
-
-         … while evaluating 'pkgs.linuxKernel.kernels.linux_4_9' to select 'meta' on it
-           at «string»:1:1:
-              1| pkgs.linuxKernel.kernels.linux_4_9.meta.description
-               | ^
-
-         … caused by explicit throw
-           at /nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source/pkgs/top-level/linux-kernels.nix:278:17:
-            277|   } // lib.optionalAttrs config.allowAliases {
-            278|     linux_4_9 = throw "linux 4.9 was removed because it will reach its end of life within 22.11";
-               |                 ^
-            279|     linux_4_14 = throw "linux 4.14 was removed because it will reach its end of life within 23.11";
-
-         error: linux 4.9 was removed because it will reach its end of life within 22.11
-  ```
-
-  Not only does the line of code that referenced the failing attribute show up in the trace, it also tells you that it was specifically the `linux_4_9` part that failed.
-
-  This includes if the failing part is a top-level binding:
-
-  ```
-  let
-    inherit (pkgs.linuxKernel.kernels) linux_4_9;
-  in linux_4_9.meta.description
-  error:
-         … while evaluating 'linux_4_9' to select 'meta.description' on it
-           at «string»:3:4:
-              2|   inherit (pkgs.linuxKernel.kernels) linux_4_9;
-              3| in linux_4_9.meta.description
-               |    ^
-
-         … while evaluating the attribute 'linux_4_9'
-           at /nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source/pkgs/top-level/linux-kernels.nix:278:5:
-            277|   } // lib.optionalAttrs config.allowAliases {
-            278|     linux_4_9 = throw "linux 4.9 was removed because it will reach its end of life within 22.11";
-               |     ^
-            279|     linux_4_14 = throw "linux 4.14 was removed because it will reach its end of life within 23.11";
-
-         … caused by explicit throw
-           at /nix/store/dk2rpyb6ndvfbf19bkb2plcz5y3k8i5v-source/pkgs/top-level/linux-kernels.nix:278:17:
-            277|   } // lib.optionalAttrs config.allowAliases {
-            278|     linux_4_9 = throw "linux 4.9 was removed because it will reach its end of life within 22.11";
-               |                 ^
-            279|     linux_4_14 = throw "linux 4.14 was removed because it will reach its end of life within 23.11";
-
-         error: linux 4.9 was removed because it will reach its end of life within 22.11
-  ```
-
-  Many thanks to [Qyriad](https://git.lix.systems/Qyriad) for this.
- Confusing 'invalid path' errors are now 'path does not exist' [cl/1161](https://gerrit.lix.systems/c/lix/+/1161) [cl/1160](https://gerrit.lix.systems/c/lix/+/1160) [cl/1159](https://gerrit.lix.systems/c/lix/+/1159)
-
-  Previously, if a path did not exist in a Nix store, it was referred to as the internal name "path is invalid".
-  This is, however, very confusing, and there were numerous such errors that were exactly the same, making it hard to debug.
-  These errors are now more specific and refer to the path not existing in the store.
-
-  Many thanks to [julia](https://git.lix.systems/midnightveil) for this.
- Add a `build-dir` setting to set the backing directory for builds [gh#10303](https://github.com/NixOS/nix/pull/10303) [gh#10312](https://github.com/NixOS/nix/pull/10312) [gh#10883](https://github.com/NixOS/nix/pull/10883) [cl/1514](https://gerrit.lix.systems/c/lix/+/1514)
-
-  `build-dir` can now be set in the Nix configuration to choose the backing directory for the build sandbox.
-  This can be useful on systems with `/tmp` on tmpfs, or simply to relocate large builds to another disk.
-
-  Also, `XDG_RUNTIME_DIR` is no longer considered when selecting the default temporary directory,
-  as it's not intended to be used for large amounts of data.
-
-  Many thanks to [Robert Hensing](https://github.com/roberth) and [Tom Bereknyei](https://github.com/tomberek) for this.
- Better usage of colour control environment variables [cl/1699](https://gerrit.lix.systems/c/lix/+/1699) [cl/1702](https://gerrit.lix.systems/c/lix/+/1702)
-
-  Lix now heeds `NO_COLOR`/`NOCOLOR` for more output types, such as that used in `nix search`, `nix flake metadata` and similar.
-
-  It also now supports `CLICOLOR_FORCE`/`FORCE_COLOR` to force colours regardless of whether there is a terminal on the other side.
-
-  It now follows rules compatible with those described on <https://bixense.com/clicolors/> with `CLICOLOR` defaulted to enabled.
-
-  That is to say, the following procedure is followed in order:
-  - NO_COLOR or NOCOLOR set
-
-    Always disable colour
-  - CLICOLOR_FORCE or FORCE_COLOR set
-
-    Enable colour
-  - The output is a tty; TERM != "dumb"
-
-    Enable colour
-  - Otherwise
-
-    Disable colour
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
- Distinguish between explicit throws and errors that happened while evaluating a throw [cl/1511](https://gerrit.lix.systems/c/lix/+/1511)
-
-  Previously, errors caused by an expression like `throw "invalid argument"` were treated like an error that happened simply while some builtin function was being called:
-
-  ```
-  let
-    throwMsg = p: throw "${p} isn't the right package";
-  in throwMsg "linuz"
-
-  error:
-         … while calling the 'throw' builtin
-           at «string»:2:17:
-              1| let
-              2|   throwMsg = p: throw "${p} isn't the right package";
-               |                 ^
-              3| in throwMsg "linuz"
-
-         error: linuz isn't the right package
-  ```
-
-  But the error didn't just happen "while" calling the `throw` builtin — it's a throw error!
-  Now it looks like this:
-
-  ```
-  let
-    throwMsg = p: throw "${p} isn't the right package";
-  in throwMsg "linuz"
-
-  error:
-         … caused by explicit throw
-           at «string»:2:17:
-              1| let
-              2|   throwMsg = p: throw "${p} isn't the right package";
-               |                 ^
-              3| in throwMsg "linuz"
-
-         error: linuz isn't the right package
-  ```
-
-  This also means that incorrect usage of `throw` or errors evaluating its arguments are easily distinguishable from explicit throws:
-
-  ```
-  let
-    throwMsg = p: throw "${p} isn't the right package";
-  in throwMsg { attrs = "error when coerced in string interpolation"; }
-
-  error:
-         … while calling the 'throw' builtin
-           at «string»:2:17:
-              1| let
-              2|   throwMsg = p: throw "${p} isn't the right package";
-               |                 ^
-              3| in throwMsg { attrs = "error when coerced in string interpolation"; }
-
-         … while evaluating a path segment
-           at «string»:2:24:
-              1| let
-              2|   throwMsg = p: throw "${p} isn't the right package";
-               |                        ^
-              3| in throwMsg { attrs = "error when coerced in string interpolation"; }
-
-         error: cannot coerce a set to a string: { attrs = "error when coerced in string interpolation"; }
-  ```
-
-  Here, instead of an actual thrown error, a type error happens first (trying to coerce an attribute set to a string), but that type error happened *while* calling `throw`.
-
-  Many thanks to [Qyriad](https://git.lix.systems/Qyriad) for this.
- `nix flake metadata` prints modified date [cl/1700](https://gerrit.lix.systems/c/lix/+/1700)
-
-  Ever wonder "gee, when *did* I update nixpkgs"?
-  Wonder no more, because `nix flake metadata` now simply tells you the times every locked flake input was updated:
-
-  ```
-  <...>
-  Description:   The purely functional package manager
-  Path:          /nix/store/c91yi8sxakc2ry7y4ac1smzwka4l5p78-source
-  Revision:      c52cff582043838bbe29768e7da232483d52b61d-dirty
-  Last modified: 2024-07-31 22:15:54
-  Inputs:
-  ├───flake-compat: github:edolstra/flake-compat/0f9255e01c2351cc7d116c072cb317785dd33b33
-  │   Last modified: 2023-10-04 06:37:54
-  ├───nix2container: github:nlewo/nix2container/3853e5caf9ad24103b13aa6e0e8bcebb47649fe4
-  │   Last modified: 2024-07-10 13:15:56
-  ├───nixpkgs: github:NixOS/nixpkgs/e21630230c77140bc6478a21cd71e8bb73706fce
-  │   Last modified: 2024-07-25 11:26:27
-  ├───nixpkgs-regression: github:NixOS/nixpkgs/215d4d0fd80ca5163643b03a33fde804a29cc1e2
-  │   Last modified: 2022-01-24 11:20:45
-  └───pre-commit-hooks: github:cachix/git-hooks.nix/f451c19376071a90d8c58ab1a953c6e9840527fd
-      Last modified: 2024-07-15 04:21:09
-  ```
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
- Hash mismatch diagnostics for fixed-output derivations include the URL [cl/1536](https://gerrit.lix.systems/c/lix/+/1536)
-
-  Now, when building fixed-output derivations, Lix will guess the URL that was used in the derivation using the `url` or `urls` properties in the derivation environment.
-  This is a layering violation but making these diagnostics tractable when there are multiple instances of the `AAAA` hash is too significant of an improvement to pass it up.
-
-  ```
-  error: hash mismatch in fixed-output derivation '/nix/store/sjfw324j4533lwnpmr5z4icpb85r63ai-x1.drv':
-          likely URL: https://meow.puppy.forge/puppy.tar.gz
-           specified: sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
-              got:    sha256-a1Qvp3FOOkWpL9kFHgugU1ok5UtRPSu+NwCZKbbaEro=
-  ```
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
- Add log formats `multiline` and `multiline-with-logs` [cl/1369](https://gerrit.lix.systems/c/lix/+/1369)
-
-  Added two new log formats (`multiline` and `multiline-with-logs`) that display
-  current activities below each other for better visibility.
-
-  These formats attempt to use the maximum available lines
-  (defaulting to 25 if unable to determine) and print up to that many lines.
-  The status bar is displayed as the first line, with each subsequent
-  activity on its own line.
-
-  Many thanks to [kloenk](https://git.lix.systems/kloenk) for this.
- Lix will now show the package descriptions in when running `nix flake show`. [cl/1540](https://gerrit.lix.systems/c/lix/+/1540)
-
-  When running `nix flake show`, Lix will now show the package descriptions, if they exist.
-
-  Before:
-
-  ```shell
-  $ nix flake show
-  path:/home/isabel/dev/lix-show?lastModified=1721736108&narHash=sha256-Zo8HP1ur7Q2b39hKUEG8EAh/opgq8xJ2jvwQ/htwO4Q%3D
-  └───packages
-      └───x86_64-linux
-          ├───aNoDescription: package 'simple'
-          ├───bOneLineDescription: package 'simple'
-          ├───cMultiLineDescription: package 'simple'
-          ├───dLongDescription: package 'simple'
-          └───eEmptyDescription: package 'simple'
-  ```
-
-  After:
-
-  ```shell
-  $ nix flake show
-  path:/home/isabel/dev/lix-show?lastModified=1721736108&narHash=sha256-Zo8HP1ur7Q2b39hKUEG8EAh/opgq8xJ2jvwQ/htwO4Q%3D
-  └───packages
-      └───x86_64-linux
-          ├───aNoDescription: package 'simple'
-          ├───bOneLineDescription: package 'simple' - 'one line'
-          ├───cMultiLineDescription: package 'simple' - 'line one'
-          ├───dLongDescription: package 'simple' - 'abcdefghijklmnopqrstuvwxyz'
-          └───eEmptyDescription: package 'simple'
-  ```
-
-  Many thanks to [kjeremy](https://github.com/kjeremy) and [isabelroses](https://git.lix.systems/isabelroses) for this.
- Eliminate some pretty-printing surprises [#11100](https://github.com/NixOS/nix/pull/11100) [cl/1616](https://gerrit.lix.systems/c/lix/+/1616) [cl/1617](https://gerrit.lix.systems/c/lix/+/1617) [cl/1618](https://gerrit.lix.systems/c/lix/+/1618)
-
-  Some inconsistent and surprising behaviours have been eliminated from the pretty-printing used by the REPL and `nix eval`:
-  * Lists and attribute sets that contain only a single item without nested structures are no longer sometimes inappropriately indented in the REPL, depending on internal state of the evaluator.
-  * Empty attribute sets and derivations are no longer shown as `«repeated»`, since they are always cheap to print.
-    This matches the existing behaviour of `nix-instantiate` on empty attribute sets.
-    Empty lists were never printed as `«repeated»` already.
-  * The REPL by default does not print nested attribute sets and lists, and indicates elided items with an ellipsis.
-    Previously, the ellipsis was printed even when the structure was empty, so that such items do not in fact exist.
-    Since this behaviour was confusing, it does not happen any more.
-
-  Before:
-  ```
-  nix-repl> :p let x = 1 + 2; in [ [ x ] [ x ] ]
-  [
-    [
-      3
-    ]
-    [ 3 ]
-  ]
-
-  nix-repl> let inherit (import <nixpkgs> { }) hello; in [ hello hello ]
-  [
-    «derivation /nix/store/fqs92lzychkm6p37j7fnj4d65nq9fzla-hello-2.12.1.drv»
-    «repeated»
-  ]
-
-  nix-repl> let x = {}; in [ x ]
-  [
-    { ... }
-  ]
-  ```
-
-  After:
-  ```
-  nix-repl> :p let x = 1 + 2; in [ [ x ] [ x ] ]
-  [
-    [ 3 ]
-    [ 3 ]
-  ]
-
-  nix-repl> let inherit (import <nixpkgs> { }) hello; in [ hello hello ]
-  [
-    «derivation /nix/store/fqs92lzychkm6p37j7fnj4d65nq9fzla-hello-2.12.1.drv»
-    «derivation /nix/store/fqs92lzychkm6p37j7fnj4d65nq9fzla-hello-2.12.1.drv»
-  ]
-
-  nix-repl> let x = {}; in [ x ]
-  [
-    { }
-  ]
-  ```
-
-  Many thanks to [alois31](https://git.lix.systems/alois31) and [Robert Hensing](https://github.com/roberth) for this.
- `nix registry add` now requires a shorthand flakeref on the 'from' side [cl/1494](https://gerrit.lix.systems/c/lix/+/1494)
-
-  The 'from' argument must now be a shorthand flakeref like `nixpkgs` or `nixpkgs/nixos-20.03`, making it harder to accidentally swap the 'from' and 'to' arguments.
-
-  Registry entries that map from other flake URLs can still be specified in registry.json, the `nix.registry` option in NixOS, or the `--override-flake` option in the CLI, but they are not guaranteed to work correctly.
-
-  Many thanks to [delan](https://git.lix.systems/delan) for this.
- Allow automatic rejection of configuration options from flakes [cl/1541](https://gerrit.lix.systems/c/lix/+/1541)
-
-  Setting `accept-flake-config` to `false` now respects user choice by automatically rejecting configuration options set by flakes.
-  The old behaviour of asking each time is still available (and default) by setting it to the special value `ask`.
-
-  Many thanks to [alois31](https://git.lix.systems/alois31) for this.
- `nix repl` now allows tab-completing the special repl :colon commands [cl/1367](https://gerrit.lix.systems/c/lix/+/1367)
-
-  The REPL (`nix repl`) supports pressing `<TAB>` to complete a partial expression, but now also supports completing the special :colon commands as well (`:b`, `:edit`, `:doc`, etc), if the line starts with a colon.
-
-  Many thanks to [Qyriad](https://git.lix.systems/Qyriad) for this.
- `:edit`ing a file in Nix store no longer reloads the repl [fj#341](https://git.lix.systems/lix-project/lix/issues/341) [cl/1620](https://gerrit.lix.systems/c/lix/+/1620)
-
-  Calling `:edit` from the repl now only reloads if the file being edited was outside of Nix store.
-  That means that all the local variables are now preserved across `:edit`s of store paths.
-  This is always safe because the store is read-only.
-
-  Many thanks to [goldstein](https://git.lix.systems/goldstein) for this.
- `:log` in repl now works on derivation paths [fj#51](https://git.lix.systems/lix-project/lix/issues/51) [cl/1716](https://gerrit.lix.systems/c/lix/+/1716)
-
-  `:log` can now accept store derivation paths in addition to derivation expressions.
-
-  Many thanks to [goldstein](https://git.lix.systems/goldstein) for this.
-
-## Fixes
- Define integer overflow in the Nix language as an error [fj#423](https://git.lix.systems/lix-project/lix/issues/423) [cl/1594](https://gerrit.lix.systems/c/lix/+/1594) [cl/1595](https://gerrit.lix.systems/c/lix/+/1595) [cl/1597](https://gerrit.lix.systems/c/lix/+/1597) [cl/1609](https://gerrit.lix.systems/c/lix/+/1609)
-
-  Previously, integer overflow in the Nix language invoked C++ level signed overflow, which was undefined behaviour, but *probably* manifested as wrapping around on overflow.
-
-  Since prior to the public release of Lix, Lix had C++ signed overflow defined to crash the process and nobody noticed this having accidentally removed overflow from the Nix language for three months until it was caught by fiddling around.
-  Given the significant body of actual Nix code that has been evaluated by Lix in that time, it does not appear that nixpkgs or much of importance depends on integer overflow, so it is safe to turn into an error.
-
-  Some other overflows were fixed:
-  - `builtins.fromJSON` of values greater than the maximum representable value in a signed 64-bit integer will generate an error.
-  - `nixConfig` in flakes will no longer accept negative values for configuration options.
-
-  Integer overflow now looks like the following:
-
-  ```
-  » nix eval --expr '9223372036854775807 + 1'
-  error: integer overflow in adding 9223372036854775807 + 1
-  ```
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
- Fix nix-collect-garbage --dry-run [fj#432](https://git.lix.systems/lix-project/lix/issues/432) [cl/1566](https://gerrit.lix.systems/c/lix/+/1566)
-
-  `nix-collect-garbage --dry-run` did not previously give any output - it simply
-  exited without even checking to see what paths would be deleted.
-
-  ```
-  $ nix-collect-garbage --dry-run
-  $
-  ```
-
-  We updated the behaviour of the flag such that instead it prints out how many
-  paths it *would* delete, but doesn't actually delete them.
-
-  ```
-  $ nix-collect-garbage --dry-run
-  finding garbage collector roots...
-  determining live/dead paths...
-  ...
-  <nix store paths>
-  ...
-  2670 store paths deleted, 0.00MiB freed
-  $
-  ```
-
-  Many thanks to [Quantum Jump](https://github.com/QuantumBJump) for this.
- Fix unexpectedly-successful GC failures on macOS [fj#446](https://git.lix.systems/lix-project/lix/issues/446) [cl/1723](https://gerrit.lix.systems/c/lix/+/1723)
-
-  Has the following happened to you on macOS? This failure has been successfully eliminated, thanks to our successful deployment of advanced successful-failure detection technology (it's just `if (failed && errno == 0)`. Patent pending<sup>not really</sup>):
-
-  ```
-  $ nix-store --gc --print-dead
-  finding garbage collector roots...
-  error: Listing pid 87261 file descriptors: Undefined error: 0
-  ```
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
- `nix copy` is now several times faster at `querying info about /nix/store/...` [fj#366](https://git.lix.systems/lix-project/lix/issues/366) [cl/1462](https://gerrit.lix.systems/c/lix/+/1462)
-
-  We fixed a locking bug that serialized `querying info about /nix/store/...`
-  onto just one thread such that it was eating `O(paths to copy * latency)` time
-  while setting up to copy paths to s3 and other stores. It is now `nproc` times
-  faster.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
-
-## Development
- clang-tidy support [fj#147](https://git.lix.systems/lix-project/lix/issues/147) [cl/1697](https://gerrit.lix.systems/c/lix/+/1697)
-
-  `clang-tidy` can be used to lint Lix with a limited set of lints using `ninja -C build clang-tidy` and `ninja -C build clang-tidy-fix`.
-  In practice, this fixes the built-in meson rule that was used the same as above being broken ever since precompiled headers were introduced.
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
- Lix now supports building with UndefinedBehaviorSanitizer [cl/1483](https://gerrit.lix.systems/c/lix/+/1483) [cl/1481](https://gerrit.lix.systems/c/lix/+/1481) [cl/1669](https://gerrit.lix.systems/c/lix/+/1669)
-
-  You can now build Lix with the configuration option `-Db_sanitize=undefined,address` and it will both work and pass tests with both AddressSanitizer and UndefinedBehaviorSanitizer enabled.
-  To use ASan specifically, you have to set `-Dgc=disabled`, which an error message will tell you to do if necessary anyhow.
-
-  Furthermore, tests passing with Clang ASan+UBSan is checked on every change in CI.
-
-  For a list of undefined behaviour found by tooling usage, see [the gerrit topic "undefined-behaviour"](https://gerrit.lix.systems/q/topic:%22undefined-behaviour%22).
-
-  Many thanks to [jade](https://git.lix.systems/jade) for this.
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Jade Lovelace	5bf891b15a	release: 2.90.0 "Vanilla Ice Cream" Release produced with releng/create_release.xsh Change-Id: Ice53891cdeafff04bd6537be66e8cd6b7dd9678c	2024-07-10 08:40:42 -07:00
Raito Bezariusandjade	f72153a510	doc/release-notes: add date for major release Change-Id: I93aab93c069bb3989c3f8d17e0862899e6f76865 Signed-off-by: Raito Bezarius <raito@lix.systems>	2024-07-10 15:35:00 +00:00
Raito Bezarius	8da08ab551	version: finalize 2.90.0 Tested by Raito, pennae and time. It looks in good shape. Change-Id: I32492557361888c28fe40553c699833876a1deab Signed-off-by: Raito Bezarius <raito@lix.systems>	2024-07-10 15:32:19 +02:00
Jade Lovelace	98d0249d5c	releng: fix broken manifest from 2.90-rc1 Well that is embarrassing. I think the proper thing is to just quickly ship a -rc2, so I will open a backport of this. $ curl https://releases.lix.systems/manifest.nix # This file was generated by releng/create_release.xsh in Lix { aarch64-linux = "/nix/store/mrbknq000af7iaqhk53bnpk1fvfrc1xp-lix-2.90.0-rc1"; aarch64-darwin = "/nix/store/z1bdccwsk34iv491aygh0mm1lgpf7yy1-lix-2.90.0-rc1"; x86_64-darwin = "/nix/store/xqvfpdhzck44v6kyhgi9f8v0xybksb6a-lix-2.90.0-rc1"; x86_64-linux = "/nix/store/h2ml0nx4477r84y82jgm8y80jpr72gqw-lix-release-tarballs"; } Change-Id: I9cf007c850c2faf995a3a9d92457517b8501d1a1	2024-06-16 19:06:45 -07:00
				`@@ -1 +0,0 @@`
				`This is a file used by the dev shell shellHook in package.nix to check that this is actually a Lix repo before installing git hooks. Its contents have no meaning.`