Re: [PATCH] t5561: get rid of racy appending to logfile

From: Jeff King <peff@peff.net>
Date: Sep 24, 2015, 18:23 UTC
Message-ID: <20150924182306.GA15647@sigill.intra.peff.net>
In-Reply-To: <1443118342-3856-1-git-send-email-s-beyer@gmx.net>

On Thu, Sep 24, 2015 at 08:12:22PM +0200, Stephan Beyer wrote:

Show 22 quoted lines

> The definition of log_div() appended information to the web server's
> logfile to make the test more readable. However, log_div() was called
> right after a request is served (which is done by git-http-backend);
> the web server waits for the git-http-backend process to exit before
> it writes to the log file. When the duration between serving a request
> and exiting was long, the log_div() output was written before the last
> request's log, and the test failed. (This duration could become
> especially long for PROFILE=GEN builds.)
> 
> To get rid of this behavior, we should not change the logfile at all.
> This commit removes log_div() and its calls. The additional information
> is kept in the test (for readability reasons) but filtered out before
> comparing it to the actual logfile.
> 
> Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
> ---
>  Okay Peff, I added the information to the commit message (in my own
>  words). Past tense for the situation before the patch, present tense
>  for the situation after (hope that's right but should not be too
>  important).
> 
>  I also used your proposed grep line because it is probably more robust.

This all looks good to me. Thanks so much for working on this.

> -cat >exp <<EOF
> +grep '^[^#]' >exp <<EOF

One quick note for others who are reviewing: this violates our usual advice to use "<<-\EOF" for here-docs, but I think it's best as-is.

We can't use "\" here because we _do_ want interpolation. The reason to use "<<-" is to match indentation with the rest of the test block. This particular content is outside a test block, which is something we typically avoid. But in this case, the expected content is essentially the whole of the script, and I think it reads a little more easily outside.

So I don't think there is anything to change, but I wanted to point out my thought process so other reviewers don't end up repeating it.

-Peff