Re: [PATCH] t/perf: handle worktrees as test repos

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> On Tue, Feb 16, 2021 at 03:12:45PM -0500, Jeff King wrote:
>
>> Having written that, it occurs to me that an even simpler solution is to
>> just always use the commondir as the source of the scratch repo. It does
>> not produce the same outcome, but the point is generally just to find a
>> suitable starting point for a repository. Grabbing the main repo instead
>> of one of its worktrees is probably OK for most tests.
>
> The patch there is delightfully simple:
>
> diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
> index e385c6896f..7018256cd4 100644
> --- a/t/perf/perf-lib.sh
> +++ b/t/perf/perf-lib.sh
> @@ -75,7 +75,7 @@ test_perf_create_repo_from () {
>  	BUG "not 2 parameters to test-create-repo"
>  	repo="$1"
>  	source="$2"
> -	source_git="$("$MODERN_GIT" -C "$source" rev-parse --git-dir)"
> +	source_git="$("$MODERN_GIT" -C "$source" rev-parse --git-common-dir)"
>  	objects_dir="$("$MODERN_GIT" -C "$source" rev-parse --git-path objects)"
>  	mkdir -p "$repo/.git"
>  	(
>
> but I do wonder if somebody would find it confusing.

That does look quite a lot simpler.

What are the possible downsides?  Per-worktree references may not be
pointing at the same objects?