Subject: Re: [PATCH 02/49] builtin/repack.c: avoid "the_repository" in existing packs API

From: Taylor Blau <[email-masked]>
Date: Fri, 10 Oct 2025 18:48:58 -0400

On Fri, Oct 10, 2025 at 01:19:55AM -0400, Jeff King wrote:
> On Sun, Sep 28, 2025 at 06:07:18PM -0400, Taylor Blau wrote:
>
> >  struct existing_packs {
> > +	struct repository *repo;
> >  	struct string_list kept_packs;
> >  	struct string_list non_kept_packs;
> >  	struct string_list cruft_packs;
> > @@ -265,7 +266,7 @@ static void existing_packs_release(struct existing_packs *existing)
> >  static void collect_pack_filenames(struct existing_packs *existing,
> >  				   const struct string_list *extra_keep)
> >  {
> > -	struct packfile_store *packs = the_repository->objects->packfiles;
> > +	struct packfile_store *packs = existing->repo->objects->packfiles;
>
> I found it a little funny to pass around a repository struct as part of
> existing_packs, since they're not directly related. But I think it is
> mostly just a convenience to do so, and "existing_packs" is really
> storing an overall context.

Yeah, the patch as-is suggests that we could have gotten away with just
adding a pointer to the packfile_store within existing_packs. I tried to
do that locally, and it works up until "builtin/repack.c: rename many
'struct existing_packs' functions", where we start to want to use
"repo", or "repo->hash_algo" :-<.

> It could probably be scoped down to pass around an object_database
> instead, or maybe even a packfile store, which somehow feels a little
> more "correct" to me as context. But I have trouble imagining that being
> helpful to any new code (why would it have an object_store but a not a
> repo object?). And I can easily imagine having the repo available being
> useful for future refactorings.
>
> So I think what you've written here is probably a good path forward. I
> wanted to outline my thinking because I suspect the same will apply to
> other patches in this series (i.e., they don't always need a repo
> object, but it's simplest to pass them one).

Yeah, exactly. In general for this series I am trying to do as few
changes to the actual functions as possible. There are some (like the
renaming in the later patch I mentioned above), but only in service of
trying to have a clean repack.h (at least from a naming standpoint).

There is lots of opportunity to clean up the repack code further. I
agree it would be nice to have existing_packs only take a
packfile_store, and pass around the repository in other places as
needed. I'm happy to investigate that, but as a follow-up to this
series, since I want to change as few things as possible here.

Thanks,
Taylor