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.