On Tue, Feb 25, 2025 at 09:21:41PM +0800, shejialuo wrote: > We always write a space after "# pack-refs with:". However, when > creating the packed-ref snapshot, we only check whether the header > starts with "# pack-refs with:". However, we need to make sure that we > would not break compatibility by tightening the rule. The following is > how some third-party libraries handle the header of "packed-ref" file. > > 1. libgit2 is fine and always writes the space. It also expects the > whitespace to exist. > 2. JGit does not expect th header to have a trailing space, but expects > the "peeled" capability to have a leading space, which is mostly > equivalent because that capability is typically the first one we > write. It always writes the space. > 3. gitoxide expects the space t exist and writes it. > 4. go-git doesn't create the header by default. > > So, we are safe to tighten the rule by checking whether the header > starts with "# pack-refs with: ". The commit message nicely describes why it's safe to do the change, but it doesn't describe why it's something we _want_ to do. Ideally, we'd be able to argue with a technical spec of the format, but unless I'm mistaken such a document does not exist. The next-best thing is to do what everyone can agree on, and that seems to be to both write and expect a space after the colon. By not following consensus that exists in other libraries we're being more loose. So if we for example started to stop writing the space due to a bug, we'd still continue to parse the header alright and thus not notice the problem, but now we have broken other implementations. That may be a good enough justification for the change itself. Patrick
