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Perl::Critic::Policy::Modules::ProhibitUseQuotedVersion − avoid quoted version number string in a "use" statement


This policy is part of the "Perl::Critic::Pulp" addon. It asks you not to quote a version number string as the sole argument to a "use" or "no" statement.

    use Foo::Bar '1.50';      # bad
    use Foo::Bar 1.50;        # ok
    no Abc::Def '2.000_010';  # bad
    no Abc::Def 2.000_010;    # ok

The unquoted form uses Perl’s builtin module version check (Perl 5.004 up) and is always enforced. The quoted form is passed to the module’s "import" and relies on it to do the check. If there’s no "import" then the quoted form is silently ignored.

"Exporter" as used by many modules provides an "import" which checks a version number arg, so those modules are fine. But the idea of this policy is to do what works always and on that basis is under the "bugs" theme (see " POLICY THEMES " in Perl::Critic).

The builtin module version check is new in Perl 5.004. For earlier versions both forms behave the same, with the string or number going through to the module "import" and so may or may not be checked. But even in code supporting older Perl it’s good to write the unquoted number so later Perl will be certain to enforce it.

The policy only applies to a single number string argument, anything else is taken to be a module parameters.

    no Abc::Def '123', 'ABC';   # ok
    use lib '..';               # ok

If you’re a bit nervous about unquoting because floating point version numbers are often not exactly representable in binary, well, yes, that’s true, but in practice it works out ok, either by converting the same way everywhere in the program or by treated as a string in the "version" module anyway.

If you’re confident about the "import()" in modules you use and prefer the string form you can always disable "ProhibitUseQuotedVersion" from your .perlcriticrc in the usual way (see " CONFIGURATION " in Perl::Critic),



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Copyright 2009, 2010, 2011, 2012 Kevin Ryde

Perl-Critic-Pulp is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

Perl-Critic-Pulp is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY ; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE . See the GNU General Public License for more details.

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