Bug#720872: perl: Perl 5.18 "randomly" loses active references under "use threads"

[Dominic Hargreaves]

On Thu, Aug 29, 2013 at 09:20:51PM +0200, Niels Thykier wrote:
> On 2013-08-29 19:41, Dominic Hargreaves wrote:
> > On Sun, Aug 25, 2013 at 10:13:39PM +0200, Niels Thykier wrote:
> >> Noticed this under the Lintian test suite:
> >>
> >> """
> >> [...]
> >> t/scripts/changelog-format.t .............................. ok
> >> ===(     314;1   0/22  0/?  1/?  0/?  0/?  0/?   5/21  0/? )============Thread 2 terminated abnormally: Can't call method "minimum_explicit_version" on an undefined value at /usr/share/perl5/Test/MinimumVersion.pm line 54.
> >> t/scripts/needs-info-exists.t ............................. ok
> >> [...]
> >> """
> >>
> >> I doubt this is a bug in Test::MinimumVersion because:
> >>  * it happens randomly
> >>  * last time I saw this problem, it happened in a different script
> >>
> >> I believe (but this is a guess) this is related to threads because I
> >> have only seen it in scripts using threads so far (and only in
> >> sections where other threads are active).
> >>
> >> Based on my observations, I would guess we are looking at a
> >> race-condition in Perl itself somewhere.  That said, I have no idea
> >> where to look for it (or how to verify this assertion).
> > 
> > Does #718438 look like the same issue? Can you reproduce it using
> > 5.18 on current sid?
> > 
> > Cheers,
> > Dominic.
> 
> I doubt it is the same issue; I never experienced it with perl5.14.
> That said, I will try when the perl transition has progressed a bit further.

Hi Niels,

Are you able to say whether this is reproducible on perl 5.20? If not,
we should probably just close this bug.

Cheers,
Dominic.