Perl::Critic::Policy::ValuesAndExpressions:: GivenWhenTryCatchLexicalDollarUnderDefaultVarBindingConfusion

[Anonymous Monk]

Perl::Critic::Policy::ValuesAndExpressions::GivenWhenTryCatchLexicalDollarUnderDefaultVarBindingConfusion

Why? See Yet more Try::Tiny problelms, Lexical $_ in given/when vs. BLOCK arguments

released under the same terms as perl itself just like Perl::Critic::Policy::ValuesAndExpressions::UndefinedBehaviourMaybeQuoteit / $1 not quoted (value not frozen) undefined behaviour

package Perl::Critic::Policy::ValuesAndExpressions::GivenWhenTryCatchL
+exicalDollarUnderDefaultVarBindingConfusion;
our $VERSION = '0.01';
use strict;
use warnings;
use Readonly;
use parent 'Perl::Critic::Policy';
use Perl::Critic::Utils qw{ :severities  };
sub supported_parameters { return ()                     }
sub default_severity     { return $SEVERITY_MEDIUM       }
sub default_themes       { return qw< bugs maintenance > }
sub applies_to           { return qw/Statement::When/    }
Readonly::Scalar my $DESC => q{lexical $_ from given/when in catch(fro
+m Try::Tiny) but you probably wanted global $_, use $::_ instead };
Readonly::Scalar my $EXPL => q{do you want my/lexical $_ or global $_?
+};

use PPIx::XPath;
use Tree::XPathEngine;

sub PPI::Node::xf {
    my( $node, $query ) = @_;
    $query = PPIx::XPath->clean_xpath_expr( $query );
    $::pxp ||= Tree::XPathEngine->new();
    return $::pxp->findnodes( $query, $node );
}

sub violates {
    my ( $self, $elem, undef ) = @_;
    
    my $globaldollar = $elem->xf(q{  .//Statement::Variable[ .=~ /\bou
+r\b.*?\$_/ ]  });
    my $catch        = $elem->xf(q{  .//Statement/Token::Word[ contain
+s(., 'catch' )  ]
// following-sibling::Structure::Block[
    contains( ., '$_' )
]
            });
    
#~     warn "### globaldollar($globaldollar)#####catch($catch) ### ";
    
    if( $catch and not $globaldollar ){
        return $self->violation( $DESC, $EXPL, $elem );
    }
    return;
}

1; # End of Perl::Critic::Policy::ValuesAndExpressions::GivenWhenTryCa
+tchLexicalDollarUnderDefaultVarBindingConfusion

[Anonymous Monk]

Refinement in the query (a catch without a try? nah ), line number inches closer to reality

sub violates {
    my ( $self, $elem, undef ) = @_;
    
    my $globaldollar = $elem->xf(q{
//Statement::Variable
/Token::Word[.='our']
/following-sibling::Token::Magic[.='$_']
    });
    
    my( $catch )     = $elem->xf(q{
.//Statement
/Token::Word[ . = 'try' ]
/following-sibling::Structure::Block
/following-sibling::Token::Word[ . = 'catch' ]
/following-sibling::Structure::Block[
    contains( ., '$_' )
]
    });
    
    if( $catch and not $globaldollar ){
        return $self->violation( $DESC, $EXPL, $catch );
    }
    return;
}