Re: Race condition in git-bundle(1) create when ref is updated while running

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 9, 2024, 17:39 UTC
Message-ID: <xmqq5xyxh6zp.fsf@gitster.g>
In-Reply-To: <87eddlpx5k.fsf@iotcl.com>

Toon Claes <toon@iotcl.com> writes:

> I discovered a bug in git-bundle(1) create. There is a race condition
> happening when a ref gets updated while the bundle creation process is
> running.

"--all" that tells "traverse from the tip of all the refs" to any rev-list family of commands (like log and bundle) eventually boils down to opendir("refs/...") followed by readdir(), and if somebody creates or deletes files while you are reading in such a loop, readdir() may appear to skip an entry, which is understandable. Even "git for-each-ref" would race with a ref update (which involves removing a file and then creating another file at the same path), I would think. IOW, I do not think this is limited to "git bundle".