Merge branch 'ps/ref-transaction-hook'

The logic to find the ref transaction hook script attempted to
cache the path to the found hook without realizing that it needed
to keep a copied value, as the API it used returned a transitory
buffer space.  This has been corrected.

* ps/ref-transaction-hook:
  t1416: avoid hard-coded sha1 ids
  refs: fix interleaving hook calls with reference-transaction hook

Author: gitster

refs.c

@@ -2044,7 +2044,7 @@ static int run_transaction_hook(struct ref_transaction *transaction,
 	if (hook == &hook_not_found)
 		return ret;
 	if (!hook)
-		hook = find_hook("reference-transaction");
+		hook = xstrdup_or_null(find_hook("reference-transaction"));
 	if (!hook) {
 		hook = &hook_not_found;
 		return ret;

t/t1416-ref-transaction-hooks.sh

@@ -7,6 +7,7 @@ test_description='reference transaction hooks'
 test_expect_success setup '
 	mkdir -p .git/hooks &&
 	test_commit PRE &&
+	PRE_OID=$(git rev-parse PRE) &&
 	test_commit POST &&
 	POST_OID=$(git rev-parse POST)
 '
@@ -106,4 +107,30 @@ test_expect_success 'hook gets all queued updates in aborted state' '
 	test_cmp expect actual
 '
 
+test_expect_success 'interleaving hook calls succeed' '
+	test_when_finished "rm -r target-repo.git" &&
+
+	git init --bare target-repo.git &&
+
+	write_script target-repo.git/hooks/reference-transaction <<-\EOF &&
+		echo $0 "$@" >>actual
+	EOF
+
+	write_script target-repo.git/hooks/update <<-\EOF &&
+		echo $0 "$@" >>actual
+	EOF
+
+	cat >expect <<-EOF &&
+		hooks/update refs/tags/PRE $ZERO_OID $PRE_OID
+		hooks/reference-transaction prepared
+		hooks/reference-transaction committed
+		hooks/update refs/tags/POST $ZERO_OID $POST_OID
+		hooks/reference-transaction prepared
+		hooks/reference-transaction committed
+	EOF
+
+	git push ./target-repo.git PRE POST &&
+	test_cmp expect target-repo.git/actual
+'
+
 test_done