oracular (3) Perl::Critic::Policy::Community::EmptyReturn.3pm.gz

Provided by: libperl-critic-community-perl_1.0.3-1_all bug

NAME
       Perl::Critic::Policy::Community::EmptyReturn - Don't use return with no arguments


DESCRIPTION
       Context-sensitive functions, while one way to write functions that DWIM (Do What I Mean), tend to instead
       lead to unexpected behavior when the function is accidentally used in a different context, especially if
       the function's behavior changes significantly based on context. This also can lead to vulnerabilities
       when a function is intended to be used as a scalar, but is used in a list, such as a hash constructor or
       function parameter list. "return" with no arguments will return either "undef" or an empty list depending
       on context. Instead, return the appropriate value explicitly.

         return;       # not ok
         return ();    # ok
         return undef; # ok

         sub get_stuff {
           return unless @things;
           return join(' ', @things);
         }
         my %stuff = (
           one => 1,
           two => get_stuff(), # oops! function returns empty list if @things is empty
           three => 3,
         );

       Empty returns are permitted by this policy if the subroutine contains no explicit return values,
       indicating it is intended to be used in void context.


CAVEATS
       This policy currently only checks return statements in named subroutines, anonymous subroutines are not
       checked. Also, return statements within blocks, other than compound statements like "if" and "foreach",
       are not considered when determining if a function is intended to be used in void context.

       Any non-empty return will cause empty returns within the same subroutine to report violations, even
       though in list context, "return" and "return ()" are functionally equivalent. It is recommended to
       explicitly specify an empty list return with "return ()" in a function that intends to return list
       context.


AFFILIATION
       This policy is part of Perl::Critic::Community.


CONFIGURATION
       This policy is not configurable except for the standard options.


AUTHOR
       Dan Book, "dbook@cpan.org"


       Copyright 2015, Dan Book.

       This library is free software; you may redistribute it and/or modify it under the terms of the Artistic
       License version 2.0.


SEE ALSO
       Perl::Critic