NAME

       Perl::Critic::Policy::ValuesAndExpressions::ProhibitComplexVersion - Prohibit version values from outside
       the module.

AFFILIATION

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

DESCRIPTION

       One tempting way to keep a group of related modules at the same version number is to have all of them
       import the version number from a designated module. For example, module "Foo::Master" could be the
       version master for the "Foo" package, and all other modules could use its $VERSION by

           use Foo::Master; our $VERSION = $Foo::Master::VERSION;

       This turns out not to be a good idea, because all sorts of unintended things can happen - anything from
       unintended version number changes to denial-of-service attacks (since "Foo::Master" is executed by the
       'use').

       This policy examines statements that assign to $VERSION, and declares a violation under two
       circumstances: first, if that statement uses a fully-qualified symbol that did not originate in a package
       declared in the file; second if there is a "use" statement on the same line that makes the assignment.

       By default, an exception is made for "use version;" because of its recommendation by Perl Best Practices.
       See the "forbid_use_version" configuration variable if you do not want an exception made for "use
       version;".

CONFIGURATION

       The construction

           use version; our $VERSION = qv('1.2.3');

       is exempt from this policy by default, because it is recommended by Perl Best Practices. Should you wish
       to identify "use version;" as a violation, add the following to your perlcriticrc file:

           [ValuesAndExpressions::ProhibitComplexVersion]
           forbid_use_version = 1

CAVEATS

       This code assumes that the hallmark of a violation is a 'use' on the same line as the $VERSION
       assignment, because that is the way to have it seen by ExtUtils::MakeMaker->parse_version(). Other ways
       to get a version value from outside the module can be imagined, and this policy is currently oblivious to
       them.

AUTHOR

       Thomas R. Wyant, III wyant at cpan dot org

COPYRIGHT

       Copyright (c) 2009-2011 Tom Wyant.

       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 v5.20.2                             Perl::Critic::Policy::ValuesAndExpressions::ProhibitComplexVersion(3pm)