Stabilize discard-references

It has been there for a few releases now (landed in 2.14.0), doesn't seem to cause any major issue and is wanted in a few places (#7087 (comment)).
NixOS · May 12, 2023 · 0e51087 · 0e51087
1 parent f60b215
commit 0e51087
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Showing 6 changed files with 11 additions and 25 deletions.
diff --git a/doc/manual/src/language/advanced-attributes.md b/doc/manual/src/language/advanced-attributes.md
@@ -320,16 +320,6 @@ Derivations can declare some infrequently used optional attributes.
     ```
 
   - [`unsafeDiscardReferences`]{#adv-attr-unsafeDiscardReferences}\
-    > **Warning**
-    > This attribute is part of an [experimental feature](@docroot@/contributing/experimental-features.md).
-    >
-    > To use this attribute, you must enable the
-    > [`discard-references`](@docroot@/contributing/experimental-features.md#xp-feature-discard-references) experimental feature.
-    > For example, in [nix.conf](../command-ref/conf-file.md) you could add:
-    >
-    > ```
-    > extra-experimental-features = discard-references
-    > ```
 
     When using [structured attributes](#adv-attr-structuredAttrs), the
     attribute `unsafeDiscardReferences` is an attribute set with a boolean value for each output name.

diff --git a/doc/manual/src/release-notes/rl-next.md b/doc/manual/src/release-notes/rl-next.md
@@ -1,2 +1,7 @@
 # Release X.Y (202?-??-??)
 
+- The `discard-references` feature has been stabilized.
+  This means that the
+  [unsafeDiscardReferences](@docroot@/contributing/experimental-features.md#xp-feature-discard-references)
+  attribute is no longer guarded by an experimental flag and can be used
+  freely.
diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
@@ -2283,7 +2283,6 @@ SingleDrvOutputs LocalDerivationGoal::registerOutputs()
         bool discardReferences = false;
         if (auto structuredAttrs = parsedDrv->getStructuredAttrs()) {
             if (auto udr = get(*structuredAttrs, "unsafeDiscardReferences")) {
-                experimentalFeatureSettings.require(Xp::DiscardReferences);
                 if (auto output = get(*udr, outputName)) {
                     if (!output->is_boolean())
                         throw Error("attribute 'unsafeDiscardReferences.\"%s\"' of derivation '%s' must be a Boolean", outputName, drvPath.to_string());

diff --git a/src/libutil/experimental-features.cc b/src/libutil/experimental-features.cc
@@ -12,7 +12,7 @@ struct ExperimentalFeatureDetails
     std::string_view description;
 };
 
-constexpr std::array<ExperimentalFeatureDetails, 13> xpFeatureDetails = {{
+constexpr std::array<ExperimentalFeatureDetails, 12> xpFeatureDetails = {{
     {
         .tag = Xp::CaDerivations,
         .name = "ca-derivations",
@@ -180,15 +180,6 @@ constexpr std::array<ExperimentalFeatureDetails, 13> xpFeatureDetails = {{
             the [`use-cgroups`](#conf-use-cgroups) setting for details.
         )",
     },
-    {
-        .tag = Xp::DiscardReferences,
-        .name = "discard-references",
-        .description = R"(
-            Allow the use of the [`unsafeDiscardReferences`](@docroot@/language/advanced-attributes.html#adv-attr-unsafeDiscardReferences) attribute in derivations
-            that use [structured attributes](@docroot@/language/advanced-attributes.html#adv-attr-structuredAttrs). This disables scanning of outputs for
-            runtime dependencies.
-        )",
-    },
     {
         .tag = Xp::DaemonTrustOverride,
         .name = "daemon-trust-override",
@@ -243,7 +234,7 @@ std::string_view showExperimentalFeature(const ExperimentalFeature tag)
     return xpFeatureDetails[(size_t)tag].name;
 }
 
-nlohmann::json documentExperimentalFeatures() 
+nlohmann::json documentExperimentalFeatures()
 {
     StringMap res;
     for (auto & xpFeature : xpFeatureDetails)

diff --git a/src/libutil/experimental-features.hh b/src/libutil/experimental-features.hh
@@ -27,7 +27,6 @@ enum struct ExperimentalFeature
     ReplFlake,
     AutoAllocateUids,
     Cgroups,
-    DiscardReferences,
     DaemonTrustOverride,
     DynamicDerivations,
 };

diff --git a/tests/check-refs.sh b/tests/check-refs.sh
@@ -42,8 +42,10 @@ nix-build -o $RESULT check-refs.nix -A test7
 nix-build -o $RESULT check-refs.nix -A test10
 
 if isDaemonNewer 2.12pre20230103; then
-    enableFeatures discard-references
-    restartDaemon
+    if ! isDaemonNewer 2.16.0; then
+        enableFeatures discard-references
+        restartDaemon
+    fi
 
     # test11 should succeed.
     test11=$(nix-build -o $RESULT check-refs.nix -A test11)