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

[Jeff King <peff@peff.net>]

On Wed, Oct 07, 2020 at 11:44:40PM -0700, Denton Liu wrote:

> diff --git a/contrib/git-resurrect.sh b/contrib/git-resurrect.sh
> index 57a77c03f9..d843df3afd 100755
> --- a/contrib/git-resurrect.sh
> +++ b/contrib/git-resurrect.sh
> @@ -37,19 +37,18 @@ search_reflog_merges () {
>  	)
>  }
>  
> -_x40="[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]"
> -_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
> +oid_pattern=$(git hash-object --stdin </dev/null | sed -e 's/./[0-9a-f]/g')

This looks correct, although...

>  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}"
>  }
>  
>  search_merge_targets () {
>  	git rev-list --all --grep="Merge branch '[^']*' into $branch\$" \
>  		--pretty=tformat:"%H %s" --all |
> -	sed -ne "/^\($_x40\) Merge .*/ {s//\1/p;$early_exit} "
> +	sed -ne "/^\($oid_pattern\) Merge .*/ {s//\1/p;$early_exit} "
>  }

in both cases we are matching output we asked for, so we really matching
[0-9a-f]\+ would be correct and sufficient. That's a little simpler. I
don't feel too strongly either way, though.

  Side note: It's a shame that there is no way to convince rev-list not
  to print the "commit ..." header, which is really what we're avoiding
  here. We probably should have suppressed it with user-formats when
  they were introduced, but it's too late to make that change. I wonder
  if it would be worth adding a command-line option, though. I've often
  had to hack around this when parsing rev-list output (and sometimes
  even resort to using git-log if it's a one-off).

-Peff