version.json: begin the 2.96 series

Change-Id: I21c37e20fc2e5786367aa9b6e5ebb7ba12eb8b6c

doc/manual/rl-next/nix-path-shadow-error.md

@@ -0,0 +1,11 @@
+---
+synopsis: "Shadowing internal files through the Nix search path is now an error"
+issues: [998]
+cls: [4632, 5370]
+category: "Breaking Changes"
+credits: [thubrecht, jade, horrors]
+---
+
+As Lix uses the path `<nix/fetchurl.nix>` for bootstrapping purposes, the ability to shadow it by adding `nix=/some/path` (or `/other/path` that contains a `nix` directory) to the search path is not desirable.
+
+Lix 2.95 deprecated this behavior with a warning, Lix 2.96 now turns it into a hard error if the `nix-path-shadow` deprecated feature isn't enabled. This deprecated feature is slated to be removed in Lix 2.98.

lix/libexpr/eval.cc

@@ -297,19 +297,19 @@ EvalPaths::EvalPaths(
         }
     }
 
-#if LIX_MAJOR >= 3 || (LIX_MAJOR == 2 && LIX_MINOR >= 96)
+#if LIX_MAJOR >= 3 || (LIX_MAJOR == 2 && LIX_MINOR >= 98)
 #warning \
-    "The feature nix-path-shadow was deprecated in 2.95 with a warning, which needs to be turned into an error in 2.96"
+    "The feature nix-path-shadow was deprecated in 2.95 with a warning, error in 2.96, and we should consider removing the bypass in 2.98"
 #endif
+
     if (!featureSettings.isEnabled(DeprecatedFeature::NixPathShadow)) {
         for (auto & [prefix, path] : searchPath_.elements) {
             // Match on the 'nix' prefix
             if (prefix.s == "nix") {
-                logWarning(
+                throw EvalError(HintFmt(
-                    {.msg = HintFmt(
                     "The prefix '%s' is reserved for internal use by Lix in the Nix search "
                     "path, its usage is deprecated and will be forbidden in the future.\n"
-                         "Use %s to silence this warning.\n"
+                    "Use %s to silence this error.\n"
                     "This is due to adding '%s=%s' in the Nix search path, either through the "
                     "environment variable '%s' or by passing the flag %s to the nix "
                     "invocation.",
@@ -319,8 +319,7 @@ EvalPaths::EvalPaths(
                     path.s,
                     "NIX_PATH",
                     "-I"
-                     )}
+                ));
-                );
             } else
                 // Match prefixless paths that contain a `nix` directory
                 if (auto res =
@@ -333,11 +332,10 @@ EvalPaths::EvalPaths(
                                 });
                         }))
                 {
-                    logWarning(
+                    throw EvalError(HintFmt(
-                        {.msg = HintFmt(
                         "Shadowing '%s' by configuring the nix-path is deprecated and "
                         "will be forbidden in the future.\n"
-                             "Use %s to silence this warning.\n"
+                        "Use %s to silence this error.\n"
                         "This is due to adding '%s' to the nix-path without a prefix, "
                         "either by passing the flag '-I %s' to the nix invocation or by "
                         "adding this path to the environment variable '%s'.",
@@ -346,8 +344,7 @@ EvalPaths::EvalPaths(
                         path.s,
                         path.s,
                         "NIX_PATH"
-                         )}
+                    ));
-                    );
                 }
         }
     }

tests/functional2/lang/search-path/eval-okay-prefixed.err.exp

@@ -1,3 +1,3 @@
-warning: The prefix 'nix' is reserved for internal use by Lix in the Nix search path, its usage is deprecated and will be forbidden in the future.
+error: The prefix 'nix' is reserved for internal use by Lix in the Nix search path, its usage is deprecated and will be forbidden in the future.
-         Use --extra-deprecated-features nix-path-shadow to silence this warning.
+       Use --extra-deprecated-features nix-path-shadow to silence this error.
        This is due to adding 'nix=nix-shadow' in the Nix search path, either through the environment variable 'NIX_PATH' or by passing the flag -I to the nix invocation.

tests/functional2/lang/search-path/eval-okay-prefixless.err.exp

@@ -1,3 +1,3 @@
-warning: Shadowing '<nix/...>' by configuring the nix-path is deprecated and will be forbidden in the future.
+error: Shadowing '<nix/...>' by configuring the nix-path is deprecated and will be forbidden in the future.
-         Use --extra-deprecated-features nix-path-shadow to silence this warning.
+       Use --extra-deprecated-features nix-path-shadow to silence this error.
        This is due to adding 'nix-shadow' to the nix-path without a prefix, either by passing the flag '-I nix-shadow' to the nix invocation or by adding this path to the environment variable 'NIX_PATH'.

tests/functional2/lang/search-path/test_search_path.py

@@ -1,7 +1,7 @@
 from collections.abc import Callable
 from pathlib import Path
 
-from lang.test_lang import test_eval_okay as nix_eval
+from lang.test_lang import test_eval_fail as nix_eval_fail, test_eval_okay as nix_eval_okay
 from testlib.fixtures.file_helper import AssetSymlink, CopyFile, CopyTree, with_files
 from testlib.fixtures.nix import Nix
 from testlib.fixtures.snapshot import Snapshot
@@ -21,7 +21,7 @@ from testlib.fixtures.snapshot import Snapshot
 )
 def test_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
     nix.env.set_env("NIX_PATH", "dir3:dir4")
-    nix_eval(
+    nix_eval_okay(
         files,
         nix,
         [
@@ -43,12 +43,26 @@ def test_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot])
         "nix-shadow": CopyTree("nix-shadow"),
         "in.nix": CopyFile("in-fetchurl.nix"),
         "out.exp": AssetSymlink("eval-okay-prefixed.out.exp"),
+    }
+)
+def test_prefixed_search_path_deprecated(
+    files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]
+):
+    nix.env.set_env("NIX_PATH", "nix=nix-shadow")
+    nix.settings.add_dp_feature("nix-path-shadow")
+    nix_eval_okay(files, nix, [], snapshot)
+
+
+@with_files(
+    {
+        "nix-shadow": CopyTree("nix-shadow"),
+        "in.nix": CopyFile("in-fetchurl.nix"),
         "err.exp": AssetSymlink("eval-okay-prefixed.err.exp"),
     }
 )
 def test_prefixed_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
     nix.env.set_env("NIX_PATH", "nix=nix-shadow")
-    nix_eval(files, nix, [], snapshot)
+    nix_eval_fail(files, nix, [], snapshot)
 
 
 @with_files(
@@ -56,11 +70,24 @@ def test_prefixed_search_path(files: Path, nix: Nix, snapshot: Callable[[str], S
         "nix-shadow": CopyTree("nix-shadow"),
         "in.nix": CopyFile("in-fetchurl.nix"),
         "out.exp": AssetSymlink("eval-okay-prefixless.out.exp"),
+    }
+)
+def test_prefixless_search_path_deprecated(
+    files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]
+):
+    nix.settings.add_dp_feature("nix-path-shadow")
+    nix_eval_okay(files, nix, ["-I", "nix-shadow"], snapshot)
+
+
+@with_files(
+    {
+        "nix-shadow": CopyTree("nix-shadow"),
+        "in.nix": CopyFile("in-fetchurl.nix"),
         "err.exp": AssetSymlink("eval-okay-prefixless.err.exp"),
     }
 )
 def test_prefixless_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
-    nix_eval(files, nix, ["-I", "nix-shadow"], snapshot)
+    nix_eval_fail(files, nix, ["-I", "nix-shadow"], snapshot)
 
 
 @with_files(
@@ -71,4 +98,4 @@ def test_prefixless_search_path(files: Path, nix: Nix, snapshot: Callable[[str],
     }
 )
 def test_empty_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
-    nix_eval(files, nix, [], snapshot)
+    nix_eval_okay(files, nix, [], snapshot)

version.json

@@ -1,5 +1,5 @@
 {
-    "version": "2.95.0",
+    "version": "2.96.0-dev",
     "official_release": false,
-    "release_name": "Kakigōri"
+    "release_name": "TBD"
 }