Re: p2000 failure due to empty reflog

[Derrick Stolee <stolee@gmail.com>]

On 10/2/2021 1:37 PM, René Scharfe wrote:
> p2000 fails for me and reports:
> 
>    perf 18 - git checkout -f - (full-v3):
>    running:
>    			(
>    				cd full-v3 &&
>    				echo >>f2/f4/a &&
>    				git checkout -f -
>    			)
> 
>    error: pathspec '-' did not match any file(s) known to git
> 
> checkout fails because the reflog is empty, so the "-" can't be
> resolved.  The pathspec error message is confusing, though.
> 
> The patch below adds a reflog entry and allows the script to
> succeed.
> 
> Before the "test_perf_on_all git commit -a -m A", there are two
> reflog entries in each of the five clones, after it there are
> none.  How is that even possible?

That is certainly confusing. Is there something about your global
(or local to your test repo) GC settings that cause an auto-GC to
prune the reflog aggressively?

> @@ -109,6 +110,14 @@ test_perf_on_all git status
>  test_perf_on_all git add -A
>  test_perf_on_all git add .
>  test_perf_on_all git commit -a -m A
> +
> +test_expect_success 'add reflog entry' '
> +	for repo in full-v3 full-v4 sparse-v3 sparse-v4
> +	do
> +		git -C $repo checkout $OLD_COMMIT
> +	done
> +'
> +
>  test_perf_on_all git checkout -f -

While I believe this will fix the situation, it might only be
a band-aid on the real problem of losing the reflog during the
test.

Thanks,
-Stolee