Hi all

Is this a bug, or just a bad regex?

   sub match {
              no warnings;
              my $value = shift @_;
              $value =~ s{^(?:aa(bb))?.*}{$1}i;
              return $value;
   }
   sub match_warn {
              use warnings;
              my $value = shift @_;
              $value =~ s{^(?:aa(bb))?.*}{$1}i;
              return $value;
   }

   print match('aabbcc')."\n";   # 'bb'
   print match('abbcc')."\n";    # ''
       
   print match_warn('aabbcc')."\n";   # 'bb'
   print match_warn('abbcc')."\n";    # Use of uninitialized value $1 
+in substitution iterator
[download]

The way I would have read that is that the capture would contain the empty string, rather than undef and so wouldn't have thrown an unintialized value warning. Is my assumption correct, which would mean that this is a bug (in 5.8.8 and 5.10), or is there a better way to write this regex.

(Note: this regex is a simplified example of a substitution which is intended to retain a part of a string (if the surrounding text matches), and if not, to set the string to the empty string).