Perl::Critic::Policy::InputOutput::ProhibitTwoArgOpen - Write open $fh, q{<}, $filename; instead of open $fh, "<$filename";.
open $fh, q{<}, $filename;
open $fh, "<$filename";
This Policy is part of the core Perl::Critic distribution.
The three-argument form of open (introduced in Perl 5.6) prevents subtle bugs that occur when the filename starts with funny characters like '>' or '<'. The IO::File module provides a nice object-oriented interface to filehandles, which I think is more elegant anyway.
open
open( $fh, '>output.txt' ); # not ok open( $fh, q{>}, 'output.txt' ); # ok use IO::File; my $fh = IO::File->new( 'output.txt', q{>} ); # even better!
It's also more explicitly clear to define the input mode of the file, as in the difference between these two:
open( $fh, 'foo.txt' ); # BAD: Reader must think what default mode is open( $fh, '<', 'foo.txt' ); # GOOD: Reader can see open mode
This policy will not complain if the file explicitly states that it is compatible with a version of perl prior to 5.6 via an include statement, e.g. by having require 5.005 in it.
require 5.005
This Policy is not configurable except for the standard options.
The only time you should use the two-argument form is when you re-open STDIN, STDOUT, or STDERR. But for now, this Policy doesn't provide that loophole.
IO::Handle
IO::File
Jeffrey Ryan Thalhammer <thaljef@cpan.org>
Copyright (C) 2005-2007 Jeffrey Ryan Thalhammer. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
To install Perl::Critic, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Perl::Critic
CPAN shell
perl -MCPAN -e shell install Perl::Critic
For more information on module installation, please visit the detailed CPAN module installation guide.