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Perl::Critic::Policy::Subroutines::ProtectPrivateSubs - Prevent access to private subs in other packages.


This Policy is part of the core Perl::Critic distribution.


By convention Perl authors (like authors in many other languages) indicate private methods and variables by inserting a leading underscore before the identifier. This policy catches attempts to access private variables from outside the package itself.

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.


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

    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. (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.)

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

    allow = FOO::_bar FOO::_baz

These are added to the default list of exemptions from this policy. Allowing a subroutine also allows the corresponding method call. So FOO::_bar in the above example allows both FOO::_bar() and FOO->_bar().


This policy is inspired by a similar test in B::Lint.


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




Chris Dolan <>


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.