find_hook: keep our own static buffer

The find_hook function returns the results of git_path,
which is a static buffer shared by other path-related calls.
Returning such a buffer is slightly dangerous, because it
can be overwritten by seemingly unrelated functions.

Let's at least keep our _own_ static buffer, so you can
only get in trouble by calling find_hook in quick
succession, which is less likely to happen and more obvious
to notice.

While we're at it, let's add some documentation of the
function's limitations.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/run-command.c b/run-command.c
index 4d73e90fa..28e1d55cb 100644
--- a/run-command.c
+++ b/run-command.c
@@ -797,11 +797,13 @@ int finish_async(struct async *async)
 
 const char *find_hook(const char *name)
 {
-	const char *path = git_path("hooks/%s", name);
-	if (access(path, X_OK) < 0)
-		path = NULL;
+	static struct strbuf path = STRBUF_INIT;
 
-	return path;
+	strbuf_reset(&path);
+	strbuf_git_path(&path, "hooks/%s", name);
+	if (access(path.buf, X_OK) < 0)
+		return NULL;
+	return path.buf;
 }
 
 int run_hook_ve(const char *const *env, const char *name, va_list args)