Re: [PATCH] t1400: avoid SIGPIPE race condition on fifo

> On Wed, Sep 15, 2021 at 01:13:25PM -0400, Jeff King wrote:
>
>> I think this test may be racy. I saw a strange failure from it in CI:
>> 
>>   https://github.com/peff/git/runs/3605506649?check_suite_focus=true#step:5:6734
>> 
>> I can't reproduce the problem locally with "--stress", but the failure
>> there is on macOS (and likewise, a nearby run failed with a timeout just
>> for macOS, which could be caused by a racy deadlock).
>
> Ah, I just wasn't trying hard enough. Using --run=1,190 lets it run a
> lot more tightly, and I got a failure pretty quickly. Here's the fix (on
> top of ps/update-ref-batch-flush).
>
> -- >8 --
> Subject: [PATCH] t1400: avoid SIGPIPE race condition on fifo
>
> t1400.190 sometimes fails or even hangs because of the way it uses
> fifos. Our goal is to interactively read and write lines from
> update-ref, so we have two fifos, in and out. We open a descriptor
> connected to "in" and redirect output to that, so that update-ref does
> not see EOF as it would if we opened and closed it for each "echo" call.