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 AND LICENSE

       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

perl v5.34.0                                2022Perl::Critic::Policy::Community::EmptyReturn(3pm)