Is there such a policy?
Here's one :-)
package Perl::Critic::Policy::ControlStructures::ProhibitGotoLabel;
use warnings;
use strict;
use base 'Perl::Critic::Policy';
use Perl::Critic::Utils qw/:severities/;
# to locate the path where to place this file, do e.g.:
# $ perl -MFile::Basename=dirname -MPerl::Critic::Policy::ControlStruc
+tures::ProhibitUnreachableCode -le 'print dirname $INC{"Perl/Critic/P
+olicy/ControlStructures/ProhibitUnreachableCode.pm"}'
# or
# $ dirname `perldoc -l Perl::Critic::Policy::ControlStructures::Prohi
+bitUnreachableCode`
our $VERSION = '0.001';
sub supported_parameters { return }
sub default_severity { return $SEVERITY_MEDIUM }
sub default_themes { return qw/core bugs/ }
sub applies_to { return 'PPI::Token::Word' }
=head1 DESCRIPTION
A C<goto LABEL> is considered a bad practice by a number of people,
as it can lead to hard-to-understand and brittle spaghetti code.
Instead of a C<goto>, use different control structures, or place a
label on a block (such as a loop's block) and use C<next LABEL>,
C<last LABEL>, or C<redo LABEL> instead.
C<goto &NAME> is very different from C<goto LABEL> and is not covered
by this policy. C<goto EXPR> is ambiguous and this policy will report
such cases when C<EXPR> does not begin with C<&>. Whether this is a
false positive or not cannot be determined by a static parse.
=cut
my $DESC = q{goto LABEL used};
my $EXPL = q{Considered bad practice};
sub violates {
my ($self, $elem) = @_;
return if $elem->content() ne 'goto';
my $target = $elem->snext_sibling();
return $self->violation('Nothing following "goto"?',
'It seems there is a lone "goto" in your code?',
$elem) if !$target;
return if $target->isa('PPI::Token::Symbol') && $target->raw_type
+eq '&'
|| $target->isa('PPI::Token::Cast') && $target->content
+eq '&'
|| $target->isa('PPI::Token::Word') && $target->content
+eq '__SUB__';
return $self->violation($DESC,$EXPL,$elem);
}
1;
Test code:
#!/usr/bin/env perl
use warnings;
use strict;
use feature 'current_sub'; # Perl 5.16, for __SUB__()
# tests for Perl::Critic::Policy::ControlStructures::ProhibitGotoLabel
# run me with e.g.: perl -c gototest.pl && perlcritic -3 gototest.pl
goto FOO; # bad
FOO:
sub foo { }
sub bar { goto &foo } # good
my $i = 1;
goto ("FOO", "BAR", "GLARCH")[$i]; # bad
BAR:
sub quz { goto __SUB__ } # good
sub quz2 { goto __SUB__() } # good
my $subref = \&foo;
sub ab { goto &$subref; } # good
sub cd { goto $subref; } # good, but false positive
my $label = "XYZ";
goto $label; # bad (but ambigious)
XYZ:
__END__
gototest.pl syntax OK
goto LABEL used at line 9, column 1. Considered bad practice. (Sever
+ity: 3)
goto LABEL used at line 16, column 1. Considered bad practice. (Seve
+rity: 3)
goto LABEL used at line 24, column 10. Considered bad practice. (Sev
+erity: 3)
goto LABEL used at line 27, column 1. Considered bad practice. (Seve
+rity: 3)
Update: Added handling of __SUB__ keyword, thanks rir!
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