Moose regularly breaks compatibility? Perhaps someone should tell its authors, who claim in Moose::Cookbook::FAQ that

The external API [...] is very stable and any changes will be 100% backwards compatible.

(emphasis theirs). Sounds to me like a module that thinks backwards-compatibility is important...

Frankly I cannot agree with EvanCarroll's recent post above. Maybe he lives in a bleeding-edge paradise where he can recklessly break his code all the time and laugh it off, but some of us work in real-world environments where breaking things is not an option. The only reason I can use Perl at all is that I can write code that will run on versions back to 5.6.1 (and it's only recently that we got rid of the last server that couldn't be upgraded beyond 5.005). This means avoiding cruft (no pseudo-hashes etc) -- but it also means avoiding new features.

Basically, any CPAN module that forced 5.10 semantics when running under 5.10 -- as EvanCarroll appears to be proposing for Moose -- will simply not be an option for me or any of the many other Perl hackers in my position. Maybe prizing backwards-compatibility so highly seems "ape shit insane" to some people, but to me the "ape shit insane" thing would be a module that changed the semantics of my code depending on the version of Perl I ran it with.