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Re: %^H (was Re: Coring Variable::Magic / autodie fights with stringeval in Perl 5.10.x)

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Vincent Pit
July 7, 2009 06:49
Re: %^H (was Re: Coring Variable::Magic / autodie fights with stringeval in Perl 5.10.x)
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> Code relying on ANYTHING in %^H in 5.8.x is broken and wrong.
> I can't see how the documentation could be any clearer than the above.
> This isn't a philosophical position that we should have "rigidly defined
> areas of doubt and uncertainty". It's a simple practical problem.
> Perl 5 is pretty bloody hard to support right now. We try hard not to break
> stuff that is documented as behaving in some fashion, and stuff that is
> ambiguous in its documented behaviour.
> It will be impossible to do anything, if people come to expect that even
> the parts that are documented as "keep off. may change without warning"
> don't change.

I don't think anyone that has used this undocumented behaviour is
expecting it to be carved in stone (or at least, I'm not - I won't nag
when it'll break). Having an official hook is definitely the solution,
but there's also a lot of older perls in the nature and it's good to
backport them the feature when it's possible and not too far fetched,
even with a few caveats (as long as they are documented).

But this definitely has a negative impact on the core development. When
the workaround just "works well enough", it's not that compelling to
contribute a complete new implementation, especially when you know that
your module will need to keep the workaround anyway, while your users
upgrade their perl.


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