Re: [PATCH v3 1/1] remote.c: fix handling of %(push:remoteref)

From: Damien Robert <damien.olivier.robert@gmail.com>
Date: Apr 16, 2020, 15:12 UTC
Message-ID: <20200416151213.xbo5x6jt477ezwvo@feanor>
In-Reply-To: <20200328133134.GA1196665@coredump.intra.peff.net>

From Jeff King, Sat 28 Mar 2020 at 09:31:34 (-0400) :

> > > I am still a bit annoyed that I cannot call branch_get_push_remoteref from
> > > branch_get_push1 because of the PUSH_DEFAULT_UPSTREAM case, but this can
> > > wait and we will need to work with the code duplication meanwhile.

> > I looked into this, too, and have a working patch. It does get a little
> > awkward, though, and I'm happy to just take your patch for now as the
> > practical thing.

Hi Jeff,

I looked up at your patch again, because the code duplication gets more annoying the more new corner cases I have to handle to get the push ref correct in all cases (cf my cover letter to v6).

This implements what I was suggesting in https://public-inbox.org/git/20200301220531.iuokzzdb5gruslrn@doriath/

Essentially in branch_get_push you call:

        remote = remote_get(pushremote_for_branch(branch, NULL));
        tracking_for_push_dest(remote, branch_get_push_remoteref(branch),

And as I pointed out, this is currently exactly what branch_get_push_1 does, except in the PUSH_DEFAULT_UPSTREAM where it returns branch->merge[0]->dst.

But branch->merge is set up in `set_merge`, where we have:

                ret->merge[i]->src = xstrdup(ret->merge_name[i]);
                if (!remote_find_tracking(remote, ret->merge[i]) ||
                    strcmp(ret->remote_name, "."))
                continue;
                if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
                             &oid, &ref) == 1)
                        ret->merge[i]->dst = ref;

So in particular, when the remote is local, the current code path calls dwim_ref. (I have no idea who set up ret->merge[i]->dst if the remote is not local...)

So my question was: can dwim_ref(branch->merge[0]->src) be different from tracking_for_push_dest(branch->merge[0]->src)?

So I admit I don't understand everything dwim_ref does, but there is at least one case where the answer is yes: if we have a dangling symref, dwim_ref which calls expand_ref in refs.c will detect it. So in the current code, %(push) would show nothing, while with your patch it would show the dangling symref.

Obviously we cannot allow a regression for this very common case ;)