Perl::Critic::Policy::Subroutines::ProhibitUnusedPrivateSubroutines(3pm)
                                           User Contributed Perl Documentation


NAME
       Perl::Critic::Policy::Subroutines::ProhibitUnusedPrivateSubroutines -
       Prevent unused private subroutines.

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

DESCRIPTION
       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 such subroutines
       which are not used in the file which declares them.

       This module defines a 'use' of a subroutine as a subroutine or method
       call to it (other than from inside the subroutine itself), a reference
       to it (i.e.  "my $foo = \&_foo"), a "goto" to it outside the subroutine
       itself (i.e.  "goto &_foo"), or the use of the subroutine's name as an
       even-numbered argument to "use overload".

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::ProhibitUnusedPrivateSubroutines]
           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:

           [Subroutines::ProhibitUnusedPrivateSubroutines]
           allow = _bar _baz

       These are added to the default list of exemptions from this policy. So
       the above allows "sub _bar {}" and "sub _baz {}", even if they are not
       referred to in the module that defines them.

       You can allow a whole class or subroutine names by defining a regular
       expression that matches allowed names.

           [Subroutines::ProhibitUnusedPrivateSubroutines]
           allow_name_regex = _build_\w+

       You can configure this policy not to check private subroutines declared
       in a file that uses one or more particular named modules.  This allows
       you to, for example, exclude unused private subroutine checking in
       classes that are roles.

           [Subroutines::ProhibitUnusedPrivateSubroutines]
           skip_when_using = Moose::Role Moo::Role Role::Tiny

HISTORY
       This policy is derived from
       Perl::Critic::Policy::Subroutines::ProtectPrivateSubs, which looks at
       the other side of the problem.

BUGS
       Does not forbid "sub Foo::_foo{}" because it does not know (and can not
       assume) what is in the "Foo" package.

       Does not respect the scope caused by multiple packages in the same
       file.  For example a file:

           package Foo;
           sub _is_private { print "A private sub!"; }

           package Bar;
           _is_private();

       Will not trigger a violation even though "Foo::_is_private" is not
       called.  Similarly, "skip_when_using" currently works on a file level,
       not on a package scope level.

SEE ALSO
       Perl::Critic::Policy::Subroutines::ProtectPrivateSubs.

AUTHOR
       Chris Dolan <cdolan@cpan.org>

COPYRIGHT
       Copyright (c) 2009-2021 Thomas R. Wyant, III.

       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.

perl v5.38.0                      2023-07-26
      Perl::Critic::Policy::Subroutines::ProhibitUnusedPrivateSubroutines(3pm)