Bug#766102: libcache-cache-perl: nondeterministic FTBFS: failure in t/6_test_size_aware_memory_cache.t

[Niko Tyni]

Package: libcache-cache-perl
Version: 1.07-1

This package failed its autopkgtest suite recently on ci.debian.org:
 http://ci.debian.net/data/packages/unstable/amd64/libc/libcache-cache-perl/20141020_123627.autopkgtest.log

 t/6_test_size_aware_memory_cache.t ......... 
 1..48
 [...]
 ok 38
 Couldn't limit size to 28 at /usr/share/perl5/Cache/CacheSizer.pm line 92.
 ok 39
 ok 40
 ok 41
 ok 42
 ok 43
 Couldn't limit size to 28 at /usr/share/perl5/Cache/CacheSizer.pm line 92.
 ok 44
 Use of uninitialized value $first_value in string eq at /usr/share/perl5/Cache/SizeAwareCacheTester.pm line 149.
 not ok 45 # failed '$first_value eq $value'
 ok 46
 ok 47
 ok 48
 Failed 1/48 subtests 
 
It's hard to reproduce, but I managed to trigger it on my own sid/amd64
system by running the test in a loop:

 while prove t/6_test_size_aware_memory_cache.t; do : ; done

which eventually (after 5-10 minutes) failed once with the same symptoms.
I also got it to trigger similarly with 'prove -b' in a just-built source
tree so it's not specific to the autopkgtest setup and can cause sporadic
build failures.

Filing at severity:normal because of the difficulty in triggering it.
Probably load related? I expect ci.debian.net is quite busy.
-- 
Niko Tyni   ntyni at debian.org