Re: [RFD/PATCH 5/5] RFD: Disallow out-of-refspec refs within refs/remotes/* to be used as upstream

Johan Herland [off-list ref] writes:

The previous patch adds validation of upstream remote-tracking branches by
parsing the configured refspecs, and making sure that the candidate upstream
(if not already matching refs/heads/* or refs/remotes/*) is indeed a
remote-tracking branch according to some remote's refspec. For a
default/conventional setup, this check would automatically also cover
everything within refs/remotes/*, meaning that the preceding check for
refs/remotes/* is redundant (although quicker than the validation against
refspecs). One could also argue that not everything inside refs/remotes/*
should be automatically acceptable as an upstream, if one were to keep
other (non-branch) type of remote-tracking refs there.

This patch removes the simple check for refs/remotes/*, to make sure that
_only_ validated remote-tracking branches (in addition to local branches)
are allowed as upstreams.

However, this means that for unconventional setups that place refs within
refs/remotes/* without configuring a corresponding refspec, those refs will
no longer be usable as upstreams. This breaks a few existing tests, which
are marked as test_expect_failure by this patch, to make them easy to find.

I think these tests are too loosely written, making assumptions on
what the back-then-current implementation actually does.

If refs/remotes/origin/koala/bear is a remote tracking branch for
koala/bear branch taken from the origin, we will have a refspec that
stores to refs/remotes/origin/koala/bear for _some_ remote (and in
the most normal case it would be "origin").

Instead of expecting failures, I think it is a better change to make
the test case more realistic by adding remote.origin.refspec as well.