Re: git auto-repack is broken...

[Jeff King <peff@peff.net>]

On Wed, Dec 07, 2011 at 07:18:13PM -0500, Nicolas Pitre wrote:

> > > Maybe  FETCH_HEAD should have a reflog too?
> > 
> > That might be nice. However, there is a complication, in that FETCH_HEAD
> > may contain many sha1s, but each reflog entry only has room for a single
> > sha1 transition. You could obviously encode it as a series of reflog
> > entries, but then "git show FETCH_HEAD@{1}" is not very meaningful.
> 
> What does "git show FETCH_HEAD" do now?  If it shows only one
> (presumably the first) SHA1 then its reflog doesn't have to be
> smarter, which would properly cover most cases already.

Are you proposing that it only store the first ref in the reflog, or
that we accept that a single fetch may write lots of reflog entries?

If the former, then you are missing the expiration/connectivity
properties.

If the latter, then it is not just "we only show the first one for
FETCH_HEAD@{1}", but also "the thing that used to be FETCH_HEAD@{1} does
not graduate to FETCH_HEAD@{2}, but rather FETCH_HEAD@{n} for some
unknown n". That may be an acceptable limitation; I just wanted to
mention it in case somebody can think of some clever solution.

> I certainly never did a multi-ref fetch myself.

Not consciously, perhaps, but you do it all the time without realizing
it:

  $ git clone git://git.kernel.org/pub/scm/git/git.git
  $ cd git
  $ git fetch -v origin
   = [up to date]      maint      -> origin/maint
   = [up to date]      master     -> origin/master
   = [up to date]      next       -> origin/next
   = [up to date]      pu         -> origin/pu
   = [up to date]      todo       -> origin/todo
  $ cat .git/FETCH_HEAD
  b1af9630d758e1728fc0008b3f18d90d8f87f4c5        not-for-merge   branch 'maint' of git://git.kernel.org/pub/scm/git/git
  4cb5d10b14dcbe0155bed9c45ccb94e83bd4c599                branch 'master' of git://git.kernel.org/pub/scm/git/git
  03e5527c5df33d4550ccc1446d861c0aa5689d58        not-for-merge   branch 'next' of git://git.kernel.org/pub/scm/git/git
  cc4e3f01fc6a5e09ae5bbdc464965981fae4cf39        not-for-merge   branch 'pu' of git://git.kernel.org/pub/scm/git/git
  7a02dba15bd28826344f9c14a5e2b5c57eeb7e50        not-for-merge   branch 'todo' of git://git.kernel.org/pub/scm/git/git

-Peff