[Reproducible-builds] Wrong reproducibility reported for libdevel-cover-perl? (i.e. I suspect a false negative)

[Axel Beckert]

Hi,

today I was debugging strange autopkgtest failures of
libdevel-cover-perl inside (!) adt-run (locally, not
yet on ci.debian.net):

  t/e2e/change.t .............. 
  Can't mkdir /home/abe/pkg-perl/libdevel-cover-perl/t/e2e/cover_db_complex_change/: No such file or directory at /usr/lib/x86_64-linux-gnu/perl5/5.22/Devel/Cover/Test.pm line 88.
  Dubious, test returned 2 (wstat 512, 0x200)

But that path there was just my local working copy where I built the
package to test it. The adt-run directory was at
/tmp/adt-run.bV4vwb/adttmp/smokeLkOAX4/. How the fuck can my path pop
up in there?

Well, libdevel-cover-perl puts the full build path into
/usr/lib/*/perl5/5*/Devel/Cover/Inc.pm and installs that file

  our $Base         = '/build/libdevel-cover-perl-ht7Bko/libdevel-cover-perl-1.21';

(This code example is taken from 1.21-1+b1 as currently in Unstable
and Testing.)

So I was sure that this package can't be built reproducible. But the
sun on
https://tests.reproducible-builds.org/rb-pkg/unstable/amd64/libdevel-cover-perl.html
still shines.

So either there is an according bug somewhere in diffoscope (which I
doubt :-) for a very long time or we should also make the second build
differ in the build directory name to catch such issues.

In case the latter is already done, I'm out of ideas why that package
counts as reproducibly buildable.

		Regards, Axel
-- 
 ,''`.  |  Axel Beckert <abe at debian.org>, http://people.debian.org/~abe/
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