Blessed are the CPAN Testers
I was doing a lot of work on Dancer lately. We've been experiencing a few test failures on Windows with the upcoming big release. I'll admit we are usually reluctant to go to Windows-land and fix issues, but Alias sure made it clear how important it really is, so it was something that had to be done at some point.
While investigating this situation, I've noticed Cwd's realpath() function was complaining a path for a test did not exist. The path did not exist for Linux or BSD either but the test wasn't failing there.
After checking out Cwd more closely, I've noticed it had an XS version for Linux, BSD and other operating systems and a few Pure-Perl implementations of realpath() for some (OS2, MSWin32, DOS, VMS, for example). Upon inspecting the XS code and the Pure-Perl code it was apparent that the versions were not exactly the same. On Windows if a path does not exist, it will croak but on Linux it will continue running.
Blessed are the CPAN Testers, for they show us the bugs!