Re: Tag peeling peculiarities

From: Michael Haggerty <mhagger@alum.mit.edu>
Date: Mar 13, 2013, 15:34 UTC
Message-ID: <51409C81.2010200@alum.mit.edu>
In-Reply-To: <51409439.5090001@alum.mit.edu>

On 03/13/2013 03:59 PM, Michael Haggerty wrote:

Show 14 quoted lines

> I have been working on the pack-refs code [1] and noticed what looks
> like a problem with the handling of peeled refs in the packed-refs file
> and in the reference cache.  In particular, the peeled versions of tags
> outside of refs/tags are *not* stored in packed-refs, but after the
> packed-refs file is read it is assumed that such tags cannot be peeled.
> 
> It is clear that annotated tags want to live under refs/tags, but there
> are some ways to create them in other places (see below).  It is not
> clear to me whether the prohibition of tags outside of refs/tags should
> be made more airtight or whether the peeling of tags outside of
> refs/tags should be fixed.
> 
> Example:
> [...]

I should have mentioned that I already understand the programmatic *cause* of the behavior that I described in my last email:

* in pack-refs.c:handle_one_ref(), tags that are not in refs/tags are
  explicitly excluded from being peeled.

* in refs.c:read_packed_refs(), if the packed-refs file starts with

      "# pack-refs with: peeled "

  then the REF_KNOWS_PEELED bit is set on *every* reference read from
  the file into the packed refs cache, whether or not it is under
  refs/tags.

* in refs.c:peel_ref(), if a refs cache entry has its REF_KNOWS_PEELED
  bit set but its peeled field is empty, then it is assumed that the
  reference is unpeelable.

What I am *not* clear about is which of these steps is incorrect, and also whether this problem will have any significant ill effects.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/