[PATCH 0/5] fix pack-refs pruning of refs/foo

[Jeff King <peff@peff.net>]

I noticed that "git pack-refs --all" will pack a top-level ref like
"refs/foo", but will not actually prune "$GIT_DIR/refs/foo". I do not
see the point in having a policy not to pack "refs/foo" if "--all" is
given. But even if we did have such a policy, this seems broken; we
should either pack and prune, or leave them untouched. I don't see any
indication that the existing behavior was intentional.

The problem is that pack-refs's prune_ref calls lock_ref_sha1, which
enforces this "no toplevel" behavior. I am not sure there is any real
point to this, given that most callers use lock_any_ref_for_update,
which is exactly equivalent but without the toplevel check.

The first two patches deal with this by switching pack-refs to use
lock_any_ref_for_update. This will conflict slightly with Ronnie's
ref-transaction work, as he gets rid of lock_ref_sha1 entirely, and
moves the code directly into prune_ref. This can be trivially resolved
in favor of my patch, I think.

The third patch is a cleanup I noticed while looking around, and I think
should not conflict with anyone (and is a good thing to do).

The last two are trickier. I wondered if we could get rid of
lock_ref_sha1 entirely. After pack-refs, there are two callers:
fast-import.c and walker.c. After converting the first, it occurred to
me that Ronnie might be touching the same areas, and I see that yes,
indeed, there's quite a bit of conflict (and he reaches the same end
goal of dropping it entirely).

So in that sense I do not mind dropping the final two patches. Ronnie's
endpoint is much better, moving to a ref_transaction. However, there is
actually a buffer overflow in the existing code. Ronnie's series fixes
it in a similar way (moving to a strbuf), and I'm fine with that
endpoint. But given that the ref transaction code is not yet merged (and
would certainly never be maint-track), I think it is worth applying the
buffer overflow fix separately.

I think the final patch can probably be dropped, then. It is a clean-up,
but one that we can just get when Ronnie's series is merged.

  [1/5]: git-prompt: do not look for refs/stash in $GIT_DIR
  [2/5]: pack-refs: prune top-level refs like "refs/foo"
  [3/5]: fast-import: clean up pack_data pointer in end_packfile
  [4/5]: fast-import: fix buffer overflow in dump_tags
  [5/5]: fast-import: stop using lock_ref_sha1

-Peff