| Subject: | Random backreferences can cause wrong behaviour |
The author appears to have wrongly expected $2 to be empty after an
unsuccessful match. This can cause buggy behaviour.
The following code shows that your last regular expression match can
cause the constructor to fail for no apparent reason:
use Mail::Bulkmail;
print "Before the match the email is ";
test_can_construct();
"Nice gotcha" =~ /(\w+) (\w+)/;
print "After the match the email is ";
test_can_construct();
sub test_can_construct {
if (Mail::Bulkmail->new()) {
print "I can construct a blank mailer\n";
}
else {
print "I can't construct a blank mailer\n";
}
}
The following isolates the function that I think the bug is in:
use Mail::Bulkmail;
my $mailer = Mail::Bulkmail->new();
print "Before the match the email is ";
test_valid();
"Nice gotcha" =~ /(\w+) (\w+)/;
print "After the match the email is ";
test_valid();
sub test_valid {
if ($mailer->valid_email('ben_tilly@operamail.com')) {
print "valid.\n";
}
else {
print "invalid.\n";
}
}
And the following code demonstrates the Perl behaviour which is
probably behind the bug.
"This gotcha is subtle." =~ /(\w+)\s+(\w+)/;
# time passes
"Some other string" =~ /(another) (pattern)/;
print "$2!\n";