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Perl::Critic::Policy::Variables::ProhibitAugmentedAssignmentInDeclaration - Do not write my $foo .= 'bar'; .


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


Variable declarations that also do initialization with '=' are common. Perl also allows you to use operators like '.=', '+=', etc., but it it is more clear to not do so.

    my $foo .= 'bar';              # same as my $foo = 'bar';
    our $foo *= 2;                 # same as our $foo = 0;
    my ( $foo, $bar ) += ( 1, 2 ); # same as my ( $foo, $bar ) = ( undef, 2 );
    local $Carp::CarpLevel += 1;   # same as local $Carp::CarpLevel = 1;
    state $foo += 2;               # adds 2 every time it's encountered

Such constructs are usually the result of botched cut-and-paste, and often are bugs. Some produce warnings.


There is an allow_our boolean option for this Policy. If set, augmented assignments are allowed when declaring our variables. Since our variables are globally accessible, some modules will want to allow users to initialize the variable prior to the module using the variable. Modules may also wish to use the same our variable in different scopes without declaring it at the outer scope.

With this option set, the following are flagged as indicated:

    our $DEBUG //= 1;           # ok

This can be enabled in your .perlcriticrc:

    allow_our = 1


Mike O'Regan


Copyright (c) 2011-2023 Mike O'Regan

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.