[PATCH 8/9] ref-filter: fix leak when formatting %(push:remoteref)
- From
Jeff King <peff@peff.net>
- Date
- Sep 9, 2024, 23:19 UTC
- Message-ID
- <20240909231951.GH921834@coredump.intra.peff.net>
- In-Reply-To
- <20240909230758.GA921697@coredump.intra.peff.net>
When we expand the %(upstream) or %(push) placeholders, we rely on remote.c's remote_ref_for_branch() to fill in the ":refname" argument. But that function has confusing memory ownership semantics: it may or may not return an allocated string, depending on whether we are in "upstream" mode or "push" mode. The caller in ref-filter.c always duplicates the result, meaning that we leak the original in the case of %(push:refname).
To solve this, let's make the return value from remote_ref_for_branch() consistent, by always returning an allocated pointer. Note that the switch to returning a non-const pointer has a ripple effect inside the function, too. We were storing the "dst" result as a const pointer, too, even though it is always allocated! It is the return value from apply_refspecs(), which is always a non-const allocated string.
And then on the caller side in ref-filter.c (and this is the only caller at all), we just need to avoid the extra duplication when the return value is non-NULL.
This clears up one case that LSan finds in t6300, but there are more.
Signed-off-by: Jeff King <peff@peff.net> --- ref-filter.c | 2 +- remote.c | 8 ++++---- remote.h | 2 +- 3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/ref-filter.c b/ref-filter.c index 370cc5b44a..0f51095bbd 100644 --- a/ref-filter.c +++ b/ref-filter.c @@ -2237,7 +2237,7 @@ static void fill_remote_ref_details(struct used_atom *atom, const char *refname, const char *merge; merge = remote_ref_for_branch(branch, atom->u.remote_ref.push); - *s = xstrdup(merge ? merge : ""); + *s = merge ? merge : xstrdup(""); } else BUG("unhandled RR_* enum"); } diff --git a/remote.c b/remote.c index 8f3dee1318..539e5ceae3 100644 --- a/remote.c +++ b/remote.c @@ -632,19 +632,19 @@ const char *pushremote_for_branch(struct branch *branch, int *explicit) static struct remote *remotes_remote_get(struct remote_state *remote_state, const char *name); -const char *remote_ref_for_branch(struct branch *branch, int for_push) +char *remote_ref_for_branch(struct branch *branch, int for_push) { read_config(the_repository, 0); die_on_missing_branch(the_repository, branch); if (branch) { if (!for_push) { if (branch->merge_nr) { - return branch->merge_name[0]; + return xstrdup(branch->merge_name[0]); } } else { - const char *dst, - *remote_name = remotes_pushremote_for_branch( + char *dst; + const char *remote_name = remotes_pushremote_for_branch( the_repository->remote_state, branch, NULL); struct remote *remote = remotes_remote_get( diff --git a/remote.h b/remote.h index b901b56746..a58713f20a 100644 --- a/remote.h +++ b/remote.h @@ -329,7 +329,7 @@ struct branch { struct branch *branch_get(const char *name); const char *remote_for_branch(struct branch *branch, int *explicit); const char *pushremote_for_branch(struct branch *branch, int *explicit); -const char *remote_ref_for_branch(struct branch *branch, int for_push); +char *remote_ref_for_branch(struct branch *branch, int for_push); /* returns true if the given branch has merge configuration given. */ int branch_has_merge_config(struct branch *branch);
-- 2.46.0.867.gf99b2b8e0f