gpg-interface: fix misdesigned signing key interfaces

The interfaces to retrieve signing keys and their IDs are misdesigned as
they return string constants even though they indeed allocate memory,
which leads to memory leaks. Refactor the code to instead always return
allocated strings and let the callers free them accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/commit.c b/commit.c
index 24ab5c1b50..ec9efc189d 100644
--- a/commit.c
+++ b/commit.c
@@ -1150,11 +1150,14 @@ int add_header_signature(struct strbuf *buf, struct strbuf *sig, const struct gi
 
 static int sign_commit_to_strbuf(struct strbuf *sig, struct strbuf *buf, const char *keyid)
 {
+	char *keyid_to_free = NULL;
+	int ret = 0;
 	if (!keyid || !*keyid)
-		keyid = get_signing_key();
+		keyid = keyid_to_free = get_signing_key();
 	if (sign_buffer(buf, sig, keyid))
-		return -1;
-	return 0;
+		ret = -1;
+	free(keyid_to_free);
+	return ret;
 }
 
 int parse_signed_commit(const struct commit *commit,