@matheusbsbs / matheus-bagliano / commits / d79fff4a11

remote: always allocate branch.push_tracking_ref

In branch_get_push(), we usually allocate a new string for the @{push} ref, but will not do so in push.default=upstream mode, where we just pass back the result of branch_get_upstream() directly. This led to a hacky memory management scheme in e291c75a95 (remote.c: add branch_get_push, 2015-05-21): we store the result in the push_tracking_ref field of a "struct branch", under the assumption that the branch struct will last until the end of the program. So even though the struct doesn't know if it has an allocated string or not, it doesn't matter because we hold on to it either way. But that assumption was violated by f5ccb535cc (remote: fix leaking config strings, 2024-08-22), which added a function to free branch structs. Any struct which is fed to branch_release() is at risk of leaking its push_tracking_ref member. I don't think this can actually be triggered in practice. We rarely actually free the branch structs, and we only fill in the push_tracking_ref string lazily when it is needed. So triggering the leak would require a code path that does both, and I couldn't find one. Still, this is an ugly trap that may eventually spring on us. Since there is only one code path in branch_get_push() that doesn't allocate, let's just have it copy the string. And then we know that push_tracking_ref is always allocated, and we can free it in branch_release(). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Jan 19, 2026 at 00:23 UTC d79fff4a11a527f57516c62fe00777852bab719a

2 files changed +5 -4

remote.c

+4 -3

@@ -272,6 +272,7 @@ static void branch_release(struct branch *branch)

272 free((char *)branch->refname);

273 free(branch->remote_name);

274 free(branch->pushremote_name);

275 + free(branch->push_tracking_ref);

276 merge_clear(branch);

277 }

278

@@ -1890,8 +1891,8 @@ static char *tracking_for_push_dest(struct remote *remote,

1891 return ret;

1892 }

1893

1893 -static const char *branch_get_push_1(struct repository *repo,

1894 - struct branch *branch, struct strbuf *err)

1894 +static char *branch_get_push_1(struct repository *repo,

1895 + struct branch *branch, struct strbuf *err)

1896 {

1897 struct remote_state *remote_state = repo->remote_state;

1898 struct remote *remote;

@@ -1931,7 +1932,7 @@ static const char *branch_get_push_1(struct repository *repo,

1932 return tracking_for_push_dest(remote, branch->refname, err);

1933

1934 case PUSH_DEFAULT_UPSTREAM:

1934 - return branch_get_upstream(branch, err);

1935 + return xstrdup_or_null(branch_get_upstream(branch, err));

1936

1937 case PUSH_DEFAULT_UNSPECIFIED:

1938 case PUSH_DEFAULT_SIMPLE:

remote.h

+1 -1

@@ -331,7 +331,7 @@ struct branch {

331

332 int merge_alloc;

333

334 - const char *push_tracking_ref;

334 + char *push_tracking_ref;

335 };

336

337 struct branch *branch_get(const char *name);