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

From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org, Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH] t/perf: handle worktrees as test repos
Date: Tue, 16 Feb 2021 14:52:57 -0800	[thread overview]
Message-ID: <xmqqtuqbocae.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <YCwoOMo7obrNOGYX@coredump.intra.peff.net> (Jeff King's message of "Tue, 16 Feb 2021 15:16:56 -0500")

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?