Re: [PATCH v2] reflog: close leak of reflog expire entry

On Thu, Jul 10, 2025 at 11:00:38AM +0800, Lidong Yan wrote:

In builtin/reflog.c, we have code like

---
	for (i = 0; i < argc; i++) {
		char *ref;
		struct expire_reflog_policy_cb cb = { .opts = opts };

		if (!repo_dwim_log(the_repository, argv[i], strlen(argv[i]), NULL, &ref)) {
			status |= error(_("reflog could not be found: '%s'"), argv[i]);
			continue;
		}
		reflog_expire_options_set_refname(&cb.opts, ref);
		status |= refs_reflog_expire(get_main_ref_store(the_repository),
					     ref, flags,
					     reflog_expiry_prepare,
					     should_prune_fn,
					     reflog_expiry_cleanup,
					     &cb);
		free(ref);
	}
+      reflog_clear_expire_config(&opts);
---

I think allowing reblog_expiry_cleanup() to free all opt->entries might
cause reblog_expire_options_set_refname() to behave incorrectly.

Hmm, yeah. We are calling this in a loop, so we'd want the config to
persist until the loop ends. I didn't test, but I'd guess that:

  git -c 'gc.refs/heads/*.reflogExpire=now' \
    reflog expire refs/heads/foo refs/heads/bar

would apply the config for "foo" but not for "bar". So I think
reflog_expiry_cleanup() has to just clean up per-traversal data, not the
config.

So the call at the end here looks reasonable, but the call in
reflog_expiry_cleanup() is wrong. I guess it was trying to cover the
call in reflog_expire_condition(). That probably just needs a manual:

diff --git a/builtin/gc.c b/builtin/gc.c
index 845876ff02..37f5437365 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c

@@ -346,6 +346,7 @@ static int reflog_expire_condition(struct gc_config *cfg UNUSED)
 				 count_reflog_entries, &data);
 
 	reflog_expiry_cleanup(&data.policy);
+	reflog_clear_expire_config(&data.policy);
 	return data.count >= data.limit;
 }
 

-Peff