Help with FTBFS polybar (builds fine on salsa-ci)

[Mattia Rizzolo]

On Sun, Jun 07, 2020 at 03:34:12PM -0700, Vagrant Cascadian wrote:
> On 2020-06-07, Samuel Henrique wrote:
> > Polybar currently FTBFS on tests.reproducible-builds.org because of a
> > timeout[0] while it builds without an issue on buildd[1] and
> > salsa-ci[2].
> 
> More accurately, it Fails to Build Reproducibly; both builds typically
> succeed do succeed, although diffoscope times out pretty consistantly:
> 
>   https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/polybar.html
> 
> 
> > Its builds are quite CPU Intensive but I believe there might be
> > something wrong going on as a timeout seems like too much.
> 
> Oh, the
> diffoscope timeout is 120m ... so that would more-or-less explain it why
> the "build" takes 2+ hours...

indeed, the "builds" by themselves are usually taking ~10 minutes each
(except on armhf), plus 2 hours of diffoscope which is the one step that
timeouts.

> Though I built polybar using reprotest, and it completed in ~22minutes,
> including two builds and running diffoscope.
> 
> 
> > I would like to clear this issue out before continuing with debugging
> > the lack of reproducibility[3].
> 
> The diffoscope output from my test with reprotest:
> 
>   https://people.debian.org/~vagrant/reproducible/polybar.diffoscope.out.gz

One thing you should consider: the build path length is varied nowadays.
This means it can very easily cause shifts in the compiled binaries even
after stripping (see the very recent bug open against debhelper to avoid
saving RPATH when using cmake).
Such thing won't happen during regular rebuilds, as the build path
lenght is usually the same even when slighly different, and as such it's
quite easier to diffoscope to build up the diff.


-- 
regards,
                        Mattia Rizzolo

GPG Key: 66AE 2B4A FCCF 3F52 DA18  4D18 4B04 3FCD B944 4540      .''`.
More about me:  https://mapreri.org                             : :'  :
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Debian QA page: https://qa.debian.org/developer.php?login=mattia  `-
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