Merge pull request #14289 from obsidiansystems/fix-14287

Fix issue #14287

Author: Ericson2314

src/libstore/build/derivation-building-goal.cc

@@ -677,7 +677,15 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
     {
         builder.reset();
         StorePathSet outputPaths;
-        for (auto & [_, output] : builtOutputs) {
+        /* In the check case we install no store objects, and so
+           `builtOutputs` is empty. However, per issue #14287, there is
+           an expectation that the post-build hook is still executed.
+           (This is useful for e.g. logging successful deterministic rebuilds.)
+
+           In order to make that work, in the check case just load the
+           (preexisting) infos from scratch, rather than relying on what
+           `DerivationBuilder` returned to us. */
+        for (auto & [_, output] : buildMode == bmCheck ? checkPathValidity(initialOutputs).second : builtOutputs) {
             // for sake of `bmRepair`
             worker.markContentsGood(output.outPath);
             outputPaths.insert(output.outPath);

tests/functional/build-hook-list-paths.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+set -x
+set -e
+
+[ -n "$OUT_PATHS" ]
+[ -n "$DRV_PATH" ]
+[ -n "$HOOK_DEST" ]
+
+for o in $OUT_PATHS; do
+    echo "$o" >> "$HOOK_DEST"
+done

tests/functional/post-hook.sh

@@ -29,6 +29,18 @@ nix-build -o "$TEST_ROOT"/result dependencies.nix --post-build-hook "$pushToStor
 export BUILD_HOOK_ONLY_OUT_PATHS=$([ ! "$NIX_TESTS_CA_BY_DEFAULT" ])
 nix-build -o "$TEST_ROOT"/result-mult multiple-outputs.nix -A a.first --post-build-hook "$pushToStore"
 
+if isDaemonNewer "2.33.0pre20251029"; then
+    # Regression test for issue #14287: `--check` should re-run post build
+    # hook, even though nothing is getting newly registered.
+    export HOOK_DEST=$TEST_ROOT/listing
+    # Needed so the hook will get the above environment variable.
+    restartDaemon
+    nix-build -o "$TEST_ROOT"/result-mult multiple-outputs.nix --check -A a.first --post-build-hook "$PWD/build-hook-list-paths.sh"
+    grepQuiet a-first "$HOOK_DEST"
+    grepQuiet a-second "$HOOK_DEST"
+    unset HOOK_DEST
+fi
+
 clearStore
 
 # Ensure that the remote store contains both the runtime and build-time