Fix passing $OUT_PATHS to the post-build hook

Fixes #6446.

src/libstore/build/derivation-goal.cc

@@ -786,8 +786,7 @@ void runPostBuildHook(
     Store & store,
     Logger & logger,
     const StorePath & drvPath,
-    StorePathSet outputPaths
-)
+    const StorePathSet & outputPaths)
 {
     auto hook = settings.postBuildHook;
     if (hook == "")
@@ -906,7 +905,7 @@ void DerivationGoal::buildDone()
         auto builtOutputs = registerOutputs();
 
         StorePathSet outputPaths;
-        for (auto & [_, output] : buildResult.builtOutputs)
+        for (auto & [_, output] : builtOutputs)
             outputPaths.insert(output.outPath);
         runPostBuildHook(
             worker.store,

tests/post-hook.sh

@@ -9,12 +9,12 @@ echo 'require-sigs = false' >> $NIX_CONF_DIR/nix.conf
 
 restartDaemon
 
-# Build the dependencies and push them to the remote store
+# Build the dependencies and push them to the remote store.
 nix-build -o $TEST_ROOT/result dependencies.nix --post-build-hook $PWD/push-to-store.sh
 
 clearStore
 
-# Ensure that we the remote store contains both the runtime and buildtime
-# closure of what we've just built
+# Ensure that the remote store contains both the runtime and build-time
+# closure of what we've just built.
 nix copy --from "$REMOTE_STORE" --no-require-sigs -f dependencies.nix
 nix copy --from "$REMOTE_STORE" --no-require-sigs -f dependencies.nix input1_drv

tests/push-to-store.sh

@@ -1,6 +1,10 @@
 #!/bin/sh
 
 set -x
+set -e
+
+[ -n "$OUT_PATHS" ]
+[ -n "$DRV_PATH" ]
 
 echo Pushing "$OUT_PATHS" to "$REMOTE_STORE"
 printf "%s" "$DRV_PATH" | xargs nix copy --to "$REMOTE_STORE" --no-require-sigs