[Reproducible-builds] automated diffoscope for parallel build bugs

[Jeremy Bicha]

On Fri, Aug 19, 2016 at 6:45 AM, Holger Levsen <holger at layer-acht.org> wrote:
> - this aint a real world scenario for our use case, which is testing and
>   working on reproducible builds. IOW: this is just another area of QA
>   work, which I agree should probably be done, but it's out of scope for
>   our project and doing it would draw "human ressources".

I believe sbuild doesn't actually build parallel by default [1] so
yes, the build could have different results when built on a
developer's personal computer then when built on the buildds.

And if parallel building is irrelevant, then why do you have the
parallel= values set differently? (Although I agree that parallel=17
compared to parallel=18 seems unlikely to find any bugs.)

> - actual tests would run a *a lot* slower, thus we would see the results
>   were are interested in, at a later time, even more disconnected from
>   the actual upload
> - the overall results would become older

I don't know anything about your resources, but if you're ever all
caught up, I think it would be useful to run a test rebuild like I
suggested. Shouldn't things slow down once we start freezing for
stretch? And if you ever do find missing translations like I found by
chance, that's surely an RC bug.

I'm not suggesting you permanently disable parallel builds on one of
your builders, just once in a while if you can.

Jeremy

[1] https://wiki.debian.org/sbuild#Building_packages