Subject: Re: [bug#72536] [PATCH v3] tap: new `--stderr-prefix' option to prefix test script's stderr

From: Jacob Bachmeyer <[email-masked]>
Date: Thu, 20 Feb 2025 18:29:30 -0600

On 2/20/25 17:23, Karl Berry wrote:
>      It's not practical to ship a C file and
>      compile that when the user runs the tests (right?).
>
> Right. Also right that we don't want to induce a dependency on
> perl/python/whatever for running tests.
>
>      (a) not piping stderr through the prefixing function when the prefix
>      is the empty string, and (b) avoiding stdout buffering when stderr
>      is prefixed.
>
> Those sound desirable in any case. Especially the first.
> It's highly desirable for existing behavior to remain the same, as much
> as possible.

Could we filter both stdout and stderr through functions that timestamp 
each line, then merge the two and sort on the timestamps?

Something like (while read line; do echo `date` "$line"; done) for the 
timestamping function?  (OK, so we would need to get high-precision 
timestamps from date(1) for that to work...)

-- Jacob