Re: Test failure when building libarchive-3.1.2

["Jan Synáček" <jan.synacek@gmail.com>]

On Fri, Nov 20, 2015 at 11:47 PM, Ludovic Courtès <ludo@gnu.org> wrote:
> Jan Synáček <jan.synacek@gmail.com> skribis:
>
>> On Fri, Nov 20, 2015 at 2:51 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>>> Jan Synáček <jan.synacek@gmail.com> skribis:
>>>
>>>> On Sat, Nov 14, 2015 at 12:40 PM, Ludovic Courtès <ludo@gnu.org> wrote:
>
> [...]
>
>>>>> It would be nice to see if this systematically fails.  If it is
>>>>> non-deterministic, we should build it with --keep-failed until it fails
>>>>> (removing successful builds with ‘guix gc -d’), collect useful info from
>>>>> the build tree, and debug.
>
> [...]
>
>>> I noticed that libarchive uses ‘readdir’ calls as-is, without sorting
>>> directory entries afterwards.  Thus, the order of directory entries is
>>> effectively non-deterministic and may change depending on the phase of
>>> the moon.
>>>
>>> This has been reported at:
>>>
>>>   https://github.com/libarchive/libarchive/issues/602
>>>
>>> Could you add the patch that’s given at that URL to the ‘patches’ field
>>> or libarchive’s ‘origin’ form and see if the problem shows up again,
>>> preferably building several times in a row?
>>
>> I built it once and it passed (note that it failed *everytime* I
>> wanted to build it).
>
> So this patch appears to solve the issue?
>
>> Maybe a dumb question, but how do I force a rebuild of an already
>> built package?:)
>
> You can’t rebuild packages because build processes are assumed to be
> deterministic.  However, you can delete a build result with ‘gc -d’, as
> mentioned above, and rebuild it afterwards.

So I've built the package several times and it worked every time. I don't even
think the build was failing non-deterministically, because, as the
commit message
of the patch explains, the unpatched bsdtar was trying to put things
like SELinux
contexts into the archive, which resulted in an archive with bigger size than
anticipated. And since I'm running guix on Fedora, I probably hit the
SELinux problem.

Thank you for helping out!

Cheers,
-- 
Jan Synáček