From: Johannes Sixt <j6t@kdbg.org>
Date: Fri, 30 Jan 2026 09:55:39 GMT
Subject: Re: [PATCH v2] t/perf/p3400: speed up setup using fast-import
Message-ID: <edc47d68-7e34-49af-b719-cef3076f6eeb@kdbg.org>
In-Reply-To: <04005f67-3ec5-4fa7-9fd7-37ef9034286a@kdbg.org>

Am 30.01.26 um 07:41 schrieb Johannes Sixt:
> Am 28.01.26 um 17:07 schrieb Tian Yuchen:
>> +
>> +	(
>> +		for i in $(test_seq 100)
>> +		do
>> +			...
>> +			cat content_rev &&
>> +			echo "EOF" || return 1
> 
> This is an incorrect use of `return` outside a function. This must be
> `|| exit 1` (or just `|| exit`) to actually break out of the loop.

I am wrong here, because my earlier tests were too narrow. This use of
`return` actually does work as intended, because it happens inside a
function. Neither the subshell nor being in the upstream of a pipe
negates this fact.

The rest of the comment still stands, though.

> Of course, the error code is ignored, because it is in the upstream of a
> pipe, so in order to fail the complete command, it would be necessary
> that the original error left an incorrect fast-import stream such that
> the down-stream `git fast-import` fails. Otherwise, the entire command
> can complete successfully in an unexpected way.
> 
> Maybe instead of a pipe, dump the stream into a temporary file, so that
> the loop's exit code can be captured?
> 
>> +		done
>> +	) | git fast-import &&
-- Hannes