Re: [PATCH 8/8] pseudo-merge.c: ensure pseudo-merge groups are closed

> Rectify this by ensuring that the commits which are pseudo-merge
> candidates can only be so if they appear somewhere in the packing order.
> 
> This is sufficient, since we know that the original packing order is
> closed under reachability, so if a commit appears in that list as a
> potential pseudo-merge candidate, we know that everything reachable from
> it also appears in the list (and thus the candidate is a good one).

> diff --git a/pseudo-merge.c b/pseudo-merge.c
> index 6422be979c..7ec9d4c51c 100644
> --- a/pseudo-merge.c
> +++ b/pseudo-merge.c
> @@ -217,6 +217,8 @@ static int find_pseudo_merge_group_for_ref(const char *refname,
>  	c = lookup_commit(the_repository, oid);
>  	if (!c)
>  		return 0;
> +	if (!packlist_find(writer->to_pack, oid))
> +		return 0;
>  
>  	has_bitmap = bitmap_writer_has_bitmapped_object_id(writer, oid);
>  

> +test_expect_success 'pseudo-merge closure' '
> +	git init pseudo-merge-closure &&
> +	(
> +		cd pseudo-merge-closure &&
> +
> +		test_commit A &&
> +		git repack -d &&
> +
> +		test_commit B &&
> +
> +		# Note that the contents of A is packed, but B is not. A
> +		# (and the objects reachable from it) are thus visible
> +		# to the MIDX, but the same is not true for B and its
> +		# objects.
> +		#
> +		# Ensure that we do not attempt to create a pseudo-merge
> +		# for B, depsite it matching the below pseudo-merge
> +		# group pattern, as doing so would result in a failure
> +		# to write a non-closed bitmap.
> +		git config bitmapPseudoMerge.test.pattern refs/ &&
> +		git config bitmapPseudoMerge.test.threshold now &&
> +
> +		git multi-pack-index write --bitmap &&