"uninitialized value in concatenation" is initialized and involves no concatenation that I can see.

hesco has asked for the wisdom of the Perl Monks concerning the following question:

I'm confused by this error message, because the values on that line are both defined and I don't see where I am concatenating anything for it to complain about. This functions is supposed to parse an email message and pull out about six or eight fields from the mix to insert into a database.

sub parse_message {
  my $self = shift;
  my $source_email = shift;

  my $found_address = 0;
  my $address_line_count = 0;
  my($name_raw,$city_state_zip);
  my($date,$email,$name,$address1,$address2,$city,$state,$zip);

  my @lines = split($/,$$source_email);
  LINE: foreach my $line (@lines){
    my $regex = '^Date:';
    print STDERR $regex, "\n";
    print STDERR $line,"\n";
    if($line =~ m/$regex/){  # <--- line 98
      $date = $line;
      $date =~ s/^Date: //;
      next LINE;
    } elsif($line =~ m/^From: /){
      # . . . etc. 
    }
  }
  return;
}
[download]

Is giving me output like:

^Date:
        by my-mx.my-host.com (Postfix) with ESMTP id 93B8DD1D6E
Use of uninitialized value in concatenation (.) or string at lib/path/
+to/mymodule.pm line 98.
[download]

Only repeated a dozen or more times for my test email I'm trying to parse.

Any and all ideas are appreciated.

-- Hugh

if( $lal && $lol ) { $life++; }

Comment on "uninitialized value in concatenation" is initialized and involves no concatenation that I can see. Select or Download Code

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Re: "uninitialized value in concatenation" is initialized and involves no concatenation that I can see. by kyle (Abbot) on Jun 26, 2008 at 21:08 UTC
Your undefined value is probably later on in the `elsif` chain. This is a common problem. `my $def1 = 'true'; my $def2 = 'foo'; my $def3 = 'blue'; my $undef1; if ( $def1 =~ /X/ ) { # <-- problem reported here print 'not here'; } elsif ( $def2 =~ /Y/ ) { print 'not here either'; } elsif ( $undef1 =~ /$def3/ ) { # <-- problem exists here print 'oh noes'; } else { print "happiness ensues\n"; }` [download]	[reply] [d/l] [select]
Re: "uninitialized value in concatenation" is initialized and involves no concatenation that I can see. by moritz (Cardinal) on Jun 26, 2008 at 21:38 UTC
BTW one of the nice improvements of perl 5.10 is that it tells you which variable is actually undefined. One more reason for upgrading ;-)	[reply]
Re: "uninitialized value in concatenation" is initialized and involves no concatenation that I can see. by ganeshk (Monk) on Jun 26, 2008 at 21:38 UTC
I suppose it is in this line `print STDERR $line,"\n";` [download] Even I have come across cases where perl slightly miscalculates the line numbers when reporting them in errors or warnings. My guess is because that's the print statement that has a concatenation. So please try to print the Dumper of @lines array and see where the undef comes in that array. Also probably seeing what $/ variable has can help diagnose further. Please also check the documentation for the split method for knowing when it can return an undef in the resulting list. Thanks, Ganesh	[reply] [d/l]
Re: "uninitialized value in concatenation" is initialized and involves no concatenation that I can see. by Anonymous Monk on Jun 27, 2008 at 05:02 UTC
It is almost certainly the 'or string' part of the 'Use of uninitialized value in concatenation (.) or string' message that is pertinent here.	[reply]