Re: [PATCH 6/8] reflog_expire(): ignore --updateref for symbolic references

[Junio C Hamano <gitster@pobox.com>]

Michael Haggerty <mhagger@alum.mit.edu> writes:

> This is a pretty exotic usage. I can't think of any real-life use case
> for using "--updateref" together with a symbolic reference. In our
> entire code base, "--updateref" is only used a single time, in
> "git-stash.sh", and that is always for "refs/stash", which is never a
> symbolic reference.

I have been wondering what the valid situation where --updateref is
a right thing to do on _any_ ref, be it a real one or a symbolic,
unless you are trying to manually fix a corrupted repository that
lack random objects left and right.  We may expire old reflog
entries and make stale objects disappear, but even when we purge all
reflog entries by expiring anything that is older than a nanosecond
ago, I do not think of a situation where we see some reflog entry
surface as the "latest" entry that points at an object that is _not_
at the tip of the actual ref.

Except for the stash, of course, as you pointed out.  We could drop
the tip (i.e. the latest) while keeping the other ones.

> "git-stash" itself is implemented in a very stylized
> way ("stylized" being a polite way of saying "bizarre"), and I doubt
> that there are many more users of this option in the wild, let alone
> "--updateref" together with a symbolic reference.
>
> So, honestly, I don't think it is worth the effort of deciding between 3
> vs. 4.

I agree with that assessment.  We might even want to start thinking
about a good strategy to remove the --updateref option command,
which in turn would need to restructure how a stash is represented.