Perl::...ateSubs(3pm)

💅 NAME

okay so bestie, this is Perl::Critic::Policy::Subroutines::ProtectPrivateSubs — the manual page lives under User Contributed Perl Documentation in section 3pm, and what it does is Prevent access to private subs in other packages. periodt. it's literally a bodyguard for your underscore-prefixed subs 🫶

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✨ AFFILIATION ✨

This Policy is part of the core Perl::Critic distribution. so it ships with the whole thing, no extra install drama 💅

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🌸 DESCRIPTION 🌸

okay so here's the vibe: by convention, Perl authors (like authors in many other languages, fr fr) indicate private methods and variables by inserting a leading underscore before the identifier. So when you see _something, that's the author going "hands off, this is mine" 🙈

This policy catches attempts to access private variables from outside the package itself. Like, don't be nosy. it's giving uninvited guest energy 😭

But! The subroutines in the POSIX package which begin with an underscore (e.g. POSIX::_POSIX_ARG_MAX) are not flagged as errors by this policy. Those get a free pass, iconic behavior honestly 👑

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🎀 CONFIGURATION 🎀

You can define what a private subroutine name looks like by specifying a regular expression for the private_name_regex option in your .perlcriticrc:

[Subroutines::ProtectPrivateSubs]
private_name_regex = _(?!_)\w+

The above example is a way of saying that subroutines that start with a double underscore are not considered to be private.

lowkey important lore: (Perl::Critic, in its implementation, uses leading double underscores to indicate a distribution-private subroutine — one that is allowed to be invoked by other Perl::Critic modules, but not by anything outside of Perl::Critic.) so that's the whole reason this regex exists, iykyk 🧚

You can also configure additional subroutines to accept by specifying them in a space-delimited list to the allow option:

[Subroutines::ProtectPrivateSubs]
allow = FOO::_bar FOO::_baz

These are added to the default list of exemptions from this policy. 💖

And here's the cute part: allowing a subroutine also allows the corresponding method call. So FOO::_bar in the above example allows both FOO::_bar() and FOO->_bar(). two for the price of one, slay ✨

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🦋 HISTORY 🦋

This policy is inspired by a similar test in B::Lint. so it's got lore, it's got lineage 👑

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💀 BUGS 💀

Doesn't forbid $pkg->_foo() because it can't tell the difference between that and $self->_foo().

yeah… it literally cannot tell bestie. the vibes are identical. a tragedy 😭

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🌈 SEE ALSO 🌈

• Perl::Critic::Policy::Variables::ProtectPrivateVars — the sibling policy, same energy, different target 🍓

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⭐ AUTHOR ⭐

Chris Dolan <cdolan@cpan.org>

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💜 COPYRIGHT 💜

Copyright (c) 2006-2011 Chris Dolan.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module.

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and that's the whole page bestie, no cap 🫶 — brought to you by perl v5.42.0, dated 2024-10-23, filed under Perl::...ateSubs(3pm). go forth and respect the underscores 💅✨