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

[Dominic Hargreaves]

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.