For some reason I don't quite understand yet, I've noticed an increasing number of core, dual life or massively-depended on modules move from having little to no CPAN Testers FAIL results to having substantial numbers.
The typical rate seems to be about 10% failures, and the list of modules is quite scary.
Scalar::Util, File::Temp, File::Spec, Exporter, base, Test::More, clone, version, Path::Class, YAML and more...
I know in at least a few of these cases they were largely FAIL-free until recently.
This problem would seem to be compounded by the situation most of the authors are in. Most are extremely busy, or have maintained these modules for a long period of time, and don't necessarily have time to push them to 100% PASS any more.
Because of recursion, failures in these modules have a HUGE impact on the userbase.
I have a small thread of work I've been trying to find time-slices for to find a way to measure this more accurately, to generate weightings for modules based on dependencies and such.
Hopefully we can then apply these weights to things like CPAN Testers results to find the "worst" bugs and modules from the perspective of the entire CPAN.
At the same time, the next phase of my own module maintenance is to ignore RT for a while and focus on CPAN Testers, to get everything up to 100% PASS.
So while there may be bugs in the code, but at least all the bugs that are tested for are confirmed to be fixed across the board.