[PATCH v3 6/6] refs: plug memory leak in repo_default_branch_name()

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Oct 22, 2021, 18:19 UTC
Message-ID: <patch-v3-6.6-d2f639b53cd-20211022T175227Z-avarab@gmail.com>
In-Reply-To: <cover-v3-0.6-00000000000-20211022T175227Z-avarab@gmail.com>

Fix a memory leak in repo_default_branch_name(), we'll leak memory before exit(128) here.

Normally we would not care much about such leaks, we do leak the memory, as e.g. valgrind(1) will report. But the more commonly used SANITIZE=leak mode will use GCC and Clang's LSAN mode will not normally report such leaks.

At least one GCC version does that in this case, and having the tests fail under -O3 would be annoying, so let's free() the allocated memory here.

This uses a new die_message() function introduced in a preceding commit. That new function makes the flow around such code easier to manage. In this case we can't free(ret) before the die().

In this case only the "free(full_ref)" appears to be needed, but since we're freeing one let's free both, some other compiler or version might arrange this code in such a way as to complain about "ret" too with SANITIZE=leak, and valgrind(1) will do so in any case.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 refs.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 7f019c2377e..2a816c9561d 100644
--- a/refs.c
+++ b/refs.c
@@ -577,6 +577,7 @@ char *repo_default_branch_name(struct repository *r, int quiet)
 	const char *config_display_key = "init.defaultBranch";
 	char *ret = NULL, *full_ref;
 	const char *env = getenv("GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME");
+	int exit_with = 0;
 
 	if (env && *env)
 		ret = xstrdup(env);
@@ -591,8 +592,13 @@ char *repo_default_branch_name(struct repository *r, int quiet)
 
 	full_ref = xstrfmt("refs/heads/%s", ret);
 	if (check_refname_format(full_ref, 0))
-		die(_("invalid branch name: %s = %s"), config_display_key, ret);
+		exit_with = die_message(_("invalid branch name: %s = %s"),
+					config_display_key, ret);
 	free(full_ref);
+	if (exit_with) {
+		free(ret);
+		exit(exit_with);
+	}
 
 	return ret;
 }

-- 
2.33.1.1494.g88b39a443e1