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>

diff --git a/run-command.c b/run-command.c
index 4d73e90fad159184bfdd204b82dd8637ad28a955..28e1d55cb934d083eaf6ba6bed04d0716da5db08 100644 (file)
--- 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)

diff --git a/run-command.h b/run-command.h
index 1103805af1b01e8396de15f48fbd06f75313fb0d..5b4425a3cbe1aea2bae40c4e060e45ee2d7a29a5 100644 (file)
--- a/run-command.h
+++ b/run-command.h
@@ -52,6 +52,11 @@ int start_command(struct child_process *);
 int finish_command(struct child_process *);
 int run_command(struct child_process *);
 
+/*
+ * Returns the path to the hook file, or NULL if the hook is missing
+ * or disabled. Note that this points to static storage that will be
+ * overwritten by further calls to find_hook and run_hook_*.
+ */
 extern const char *find_hook(const char *name);
 LAST_ARG_MUST_BE_NULL
 extern int run_hook_le(const char *const *env, const char *name, ...);