From: Patrick Steinhardt <ps@pks.im>
Date: Mon, 07 Sep 2026 07:49:56 GMT
Subject: Re: [PATCH v2 02/13] cache-tree: remove dependency on `the_repository`
Message-ID: <ap5spPyWgga9b315@pks.im>
In-Reply-To: <CAOLa=ZQ=oCDtjAQXNXe51DvKUCCk0CK1EuM+QKhJ3iH8YiS+mw@mail.gmail.com>

On Fri, Sep 04, 2026 at 03:28:07PM -0700, Karthik Nayak wrote:
> Patrick Steinhardt <ps@pks.im> writes:
> 
> > The "cache-tree" subsystem still depends on `the_repository`. Adapt it
> > to instead use repositories provided via the context, either as a new
> > parameter or the one passed in via `struct index_state`.
> >
> > Besides getting rid of `the_repository`, this also removes the last
> > dependency on registering submodule sources with the main object
> > database. When reading gitmodules from a submodule's index we implicitly
> > read that object via `the_repository`'s object database, which is of
> > course wrong. This works though because we would then register the
> > submodule's object database with the main object database, but a later
> > patch is going to get rid of that mechanism.
> >
> > You can verify that we indeed no longer depend on this mechanism by
> > running tests with `GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=true`. Without
> > this patch we fail in t1092, with this patch we never register submodule
> > object databases anymore.
> >
> 
> Interesting, to sum up if I understand correctly, somewhere in the call
> chain of looking up the gitmodules from the submodules index, we end up
> using 'the_repository' instead of the submodule's repo structure.
> 
> This is of course wrong, because we use the wrong repo, the consequence
> is that the lookup fails, but we have a last ditch effort of adding all
> submodules as alternates and retrying the object read, this succeeds.
> 
> So this patch fixes the repository being correctly passed down. Meaning
> we no longer need to add the submodules as an alternate.

Yup, exactly this.

Patrick