Re: [PATCH 2/2] contrib/git-resurrect.sh: use hash-agnostic OID pattern

[Jeff King <peff@peff.net>]

On Fri, Oct 09, 2020 at 09:55:53AM +0200, Andreas Schwab wrote:

> >> >  search_merges () {
> >> >  	git rev-list --all --grep="Merge branch '$1'" \
> >> >  		--pretty=tformat:"%P %s" |
> >> > -	sed -ne "/^$_x40 \($_x40\) Merge .*/ {s//\1/p;$early_exit}"
> >> > +	sed -ne "/^$oid_pattern \($oid_pattern\) Merge .*/ {s//\1/p;$early_exit}"
> [...]
> I wonder why --pretty uses %s when it is filtered out again anyway?
> (There is also a duplicate --all.)

It does confirm that the commit in question is a (likely) merge commit,
and not one that happens to have "Merge branch 'foo'" in the body, which
the earlier --grep would have hit. But it doesn't actually check for
'foo' in the sed match, so it would be fooled by a commit message like:

  Merge branch 'bar'

    * bar:
      Merge branch 'foo'

If we wanted to tighten that up, then sed should match the branch name.
If we're willing to accept the looseness, the whole thing could probably
be:

  git rev-list --all --grep="Merge branch '$1'" \
    --min-parents 2 --parents ${early_exit:-"-1"} |
  awk '{print $3}'

I'm happy either way, but I'm not sure anybody overly cares. Let's not
derail Denton's actual fix to make the script work in a sha256 world.

-Peff