[PATCH v3 05/19] update-ref.c: use the error string from _commit to print better message

@@ -342,6 +342,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 	const char *refname, *oldval, *msg = NULL;
 	unsigned char sha1[20], oldsha1[20];
 	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0, flags = 0;
+	char *err;
 	struct option options[] = {
 		OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 		OPT_BOOL('d', NULL, &delete, N_("delete the reference")),

@@ -359,17 +360,18 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		die("Refusing to perform update with empty message.");
 
 	if (read_stdin) {
-		int ret;
 		transaction = ref_transaction_begin();
-
+		if (!transaction)
+			die("failed to update refs");
 		if (delete || no_deref || argc > 0)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
 			line_termination = '\0';
 		update_refs_stdin();
-		ret = ref_transaction_commit(transaction, msg, NULL,
-					     UPDATE_REFS_DIE_ON_ERR);
-		return ret;
+		if (ref_transaction_commit(transaction, msg, &err,
+					   UPDATE_REFS_QUIET_ON_ERR))
+			die("update_ref failed: %s", err);
+		return 0;
 	}
 
 	if (end_null)

@@ -453,7 +453,7 @@ test_expect_success 'stdin fails with duplicate refs' '
 	create $a $m
 	EOF
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: Multiple updates for ref '"'"'$a'"'"' not allowed." err
+	grep "fatal: update_ref failed: Multiple updates for ref '"'"'$a'"'"' not allowed." err
 '
 
 test_expect_success 'stdin create ref works' '

@@ -511,7 +511,7 @@ test_expect_success 'stdin create ref works with path with space to blob' '
 test_expect_success 'stdin update ref fails with wrong old value' '
 	echo "update $c $m $m~1" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+	grep "fatal: update_ref failed: Cannot lock the ref '"'"'$c'"'"'" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 

@@ -547,7 +547,7 @@ test_expect_success 'stdin update ref works with right old value' '
 test_expect_success 'stdin delete ref fails with wrong old value' '
 	echo "delete $a $m~1" >stdin &&
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: Cannot lock the ref '"'"'$a'"'"'" err &&
+	grep "fatal: update_ref failed: Cannot lock the ref '"'"'$a'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual

@@ -634,7 +634,7 @@ test_expect_success 'stdin update refs fails with wrong old value' '
 	update $c  ''
 	EOF
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+	grep "fatal: update_ref failed: Cannot lock the ref '"'"'$c'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual &&

@@ -807,7 +807,7 @@ test_expect_success 'stdin -z fails option with unknown name' '
 test_expect_success 'stdin -z fails with duplicate refs' '
 	printf $F "create $a" "$m" "create $b" "$m" "create $a" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: Multiple updates for ref '"'"'$a'"'"' not allowed." err
+	grep "fatal: update_ref failed: Multiple updates for ref '"'"'$a'"'"' not allowed." err
 '
 
 test_expect_success 'stdin -z create ref works' '

@@ -847,7 +847,7 @@ test_expect_success 'stdin -z create ref works with path with space to blob' '
 test_expect_success 'stdin -z update ref fails with wrong old value' '
 	printf $F "update $c" "$m" "$m~1" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+	grep "fatal: update_ref failed: Cannot lock the ref '"'"'$c'"'"'" err &&
 	test_must_fail git rev-parse --verify -q $c
 '
 

@@ -883,7 +883,7 @@ test_expect_success 'stdin -z update ref works with right old value' '
 test_expect_success 'stdin -z delete ref fails with wrong old value' '
 	printf $F "delete $a" "$m~1" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: Cannot lock the ref '"'"'$a'"'"'" err &&
+	grep "fatal: update_ref failed: Cannot lock the ref '"'"'$a'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual

@@ -952,7 +952,7 @@ test_expect_success 'stdin -z update refs fails with wrong old value' '
 	git update-ref $c $m &&
 	printf $F "update $a" "$m" "$m" "update $b" "$m" "$m" "update $c" "$m" "$Z" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: Cannot lock the ref '"'"'$c'"'"'" err &&
+	grep "fatal: update_ref failed: Cannot lock the ref '"'"'$c'"'"'" err &&
 	git rev-parse $m >expect &&
 	git rev-parse $a >actual &&
 	test_cmp expect actual &&