Re: [PATCH 3/3] test-lib: add a few comments to LSan log checking

[Patrick Steinhardt <ps@pks.im>]

On Tue, Jan 07, 2025 at 02:08:31AM -0500, Jeff King wrote:
> Commit b119a687d4 (test-lib: ignore leaks in the sanitizer's thread
> code, 2025-01-01) added code to suppress a false positive in the leak
> checker. But if you're just reading the code, the obscure grep call is a
> bit of a head-scratcher. Let's add a brief comment explaining what's
> going on (and anybody digging further can find this commit or that one
> for all the details).
> 
> Signed-off-by: Jeff King <peff@peff.net>
> ---
>  t/test-lib.sh | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/t/test-lib.sh b/t/test-lib.sh
> index 898c2267b8..9f27a49995 100644
> --- a/t/test-lib.sh
> +++ b/t/test-lib.sh
> @@ -1172,6 +1172,11 @@ test_atexit_handler () {
>  check_test_results_san_file_has_entries_ () {
>  	test -z "$TEST_RESULTS_SAN_FILE" && return 1
>  
> +	# Lines marked with DEDUP_TOKEN show unique leaks. We only care that we
> +	# found at least one.
> +	#
> +	# But also suppress any false positives caused by bugs or races in the
> +	# sanitizer itself.
>  	grep -s ^DEDUP_TOKEN "$TEST_RESULTS_SAN_FILE".* |
>  	grep -qv sanitizer::GetThreadStackTopAndBottom
>  }

Thanks for adding this comment!

Patrick