Re: [RFC PATCH] vreportf: ensure sensible ordering of normal and error output

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 2, 2021, 00:43 UTC
Message-ID: <xmqq35nbygxs.fsf@gitster.g>
In-Reply-To: <211201.86mtlk9fx4.gmgdl@evledraar.gmail.com>

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

Show 11 quoted lines

>> Here's a past discussion (that actually goes the other way: somebody
>> complaining that stderr should be on stdout!) where I laid out my mental
>> model:
>>
>>   https://lore.kernel.org/git/20110907215716.GJ13364@sigill.intra.peff.net/
>
> ...and a third way (which git doesn't conform to at all), which is that
> std*err* is really what we should be using for errors only.
>
> You shouldn't write anything that isn't an error there, or at least
> that's what I've seen some software in the wild assume.

That is already covered in the old thread Peff cited (not in the message from Peff, but you can find what others said on the topic back then from that page). We saw programs that declare any output to standard error by programs they spawn indicates an error, instead of checking the exit status of the programs they spawn, which would of course break when they try to drive git.