Perl::...ersion(3pm)

okay so bestie 💖 welcome to the Perl::Critic::Policy::ValuesAndExpressions::ProhibitComplexVersion manual page — yep, the one whose header gets squished down to Perl::...ersion(3pm) — brought to you by User Contributed Perl Documentation. grab a strawberry 🍓 and let’s get into it.

🌸 NAME 🌸

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

🎀 AFFILIATION 🎀

This Policy is part of the core Perl::Critic distribution. iconic behavior, honestly 👑.

✨ DESCRIPTION ✨

okay so here’s the tempting idea: keep a whole group of related modules at the same version number by having all of them import the version number from one designated module. for example, module Foo::Master could be the version master for the Foo package, and all the other modules could use its $VERSION like this:

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

and ngl, this turns out not to be a good idea 😭. 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 it 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

slay, that’s the whole config vibe 🎀✨

💀 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. no cap, that’s the caveat 🫶.

🌈 AUTHOR 🌈

Thomas R. Wyant, III wyant at cpan dot org

💜 COPYRIGHT 💜

Copyright (c) 2009-2023 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. periodt 💅

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