[buildd-tools-devel] Bug#808560: Bug#808560: sbuild: Use of uninitialized value $_ in concatenation (.)

[Niko Tyni]

On Tue, Dec 22, 2015 at 07:48:11AM +0100, Johannes Schauer wrote:
> Quoting Niko Tyni (2015-12-21 23:43:24)
> > My preliminary findings are that a change in Perl broke the sbuild parsing of
> > .changes files, in lib/Sbuild/Build.pm:1865 or so.
> > 
> > This has different behaviour on 5.20 and 5.22:
> > 
> > perl -MData::Dumper -e '@a=(split( /\s+/, "foo"))[5]; print Dumper \@a'
> > 
> > which shows an empty array on 5.20 and an array of one undef element
> > on 5.22.
> > 
> > I'm not yet sure if this is a regression in Perl or a bugfix.
> > Will follow up later when I know more. Marking this as blocking the Perl
> > transition to testing for now.

FWIW it turns out it's a bugfix not a regression in Perl. The relevant
perl5220delta entry is

  List slices now return an empty list only if the original list was
  empty (or if there are no indices). Formerly, a list slice would
  return an empty list if all indices fell outside the original list;
  now it returns a list of undef values in that case. [perl #114498].

and the gory details are at
 https://rt.perl.org/Public/Bug/Display.html?id=114498

> 
> If the problem is this change of behaviour as you described it, then the fix is
> a very simple one:

Cool, thanks! I'm not sure if there are other problems, this was the
one I found first.
-- 
Niko Tyni   ntyni at debian.org