Subject: Re: [PATCH] Fix filter-branch to eliminate duplicate mapped parents

From: Junio C Hamano <[email-masked]>
Date: Tue, 01 Jul 2014 08:03:46 -0700

Charles Bailey <[email-masked]> writes:

> I worked on this after discovering that --prune-empty often left some
> apparently empty commits that I was wasn't expecting it to leave and
> that running filter-branch --prune-empty in a loop would often do many
> passes where it was still pruning empty former merge commits.

Good find.

>
> The test is a simple example of such a case. A non-ff merge of a commit
> that only changes a file that is to be pruned gets squashed into an
> empty non-merge commit that should be pruned.
>
>  git-filter-branch.sh     |  8 +++++++-
>  t/t7003-filter-branch.sh | 11 +++++++++++
>  2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/git-filter-branch.sh b/git-filter-branch.sh
> index 86d6994..c5b82a8 100755
> --- a/git-filter-branch.sh
> +++ b/git-filter-branch.sh
> @@ -332,7 +332,13 @@ while read commit parents; do
>  	parentstr=
>  	for parent in $parents; do
>  		for reparent in $(map "$parent"); do
> -			parentstr="$parentstr -p $reparent"
> +			case "$parentstr" in
> +				*" -p $reparent"*)
> +					;;
> +				*)
> +					parentstr="$parentstr -p $reparent"
> +					;;
> +			esac

The case arms seem to be indented one level too deep; I'll fix it up
locally when queuing, so no need to resend.

Thanks.