Do not pass special variables to subroutines directly

[KES777]

Why:

#!/usr/bin/env perl

sub test {
	'asdf' =~ m/.*/; # This destroys received arguments
	print ">>@_<<\n";

}

my $z =  'abcd';
$z =~ m/(ab)(cd)/;
test( $1, $2 );                # >> <<
test( my $x=$1, my $y=$2 );    # >>ab cd<<

How regular expression could be executed when sub is called? This could occur under debugger. For example some module define sub sub and used regex inside that sub

[tobyink]

I'm not sure why you submitted this as an issue for Exporter::Tiny as it seems unrelated.

But it is because @_ acts as an alias for the arguments passed to the function, not a copy. By doing m/.*/, you destroy $1 and $2, and @_ was only ever an alias of them, not a copy of them, so the values in it get destroyed too.

[KES777]

@tobyink
$1 is destroyed.

https://github.com/tobyink/p5-exporter-tiny/blob/master/lib/Exporter/Tiny.pm#L26 (please also fix other places)

Would be better if you pass "$1" instead $1

[KES777]

I submitted because Exporter::Tiny uses $1 as parameter.