Fix test

Author: edolstra

src/libstore/gc.cc

@@ -717,6 +717,15 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                 } catch (InvalidPath &) { }
             };
 
+            if (options.action == GCOptions::gcDeleteSpecific
+                && !options.pathsToDelete.count(*path))
+            {
+                throw Error(
+                    "Cannot delete path '%s' because it's referenced by path '%s'.",
+                    printStorePath(start),
+                    printStorePath(*path));
+            }
+
             /* If this is a root, bail out. */
             if (auto i = roots.find(*path); i != roots.end()) {
                 if (options.action == GCOptions::gcDeleteSpecific)
@@ -728,15 +737,6 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                 return markAlive();
             }
 
-            if (options.action == GCOptions::gcDeleteSpecific
-                && !options.pathsToDelete.count(*path))
-            {
-                throw Error(
-                    "Cannot delete path '%s' because it's referenced by path '%s'.",
-                    printStorePath(start),
-                    printStorePath(*path));
-            }
-
             {
                 auto hashPart = std::string(path->hashPart());
                 auto shared(_shared.lock());

tests/functional/gc.sh

@@ -23,7 +23,7 @@ if nix-store --gc --print-dead | grep -E "$outPath"$; then false; fi
 nix-store --gc --print-dead
 
 inUse=$(readLink "$outPath/reference-to-input-2")
-expectStderr 1 nix-store --delete "$inUse" | grepQuiet "Cannot delete path.*because it's referenced by the GC root "
+expectStderr 1 nix-store --delete "$inUse" | grepQuiet "Cannot delete path.*because it's referenced by path '"
 test -e "$inUse"
 
 expectStderr 1 nix-store --delete "$outPath" | grepQuiet "Cannot delete path.*because it's referenced by the GC root "