Dear monks,

I just had a look at the function first in the Module List::Util and found the following code:

sub first (&@) {
  my $code = shift;

  foreach (@_) {
    return $_ if &{$code}();
  }

  undef; # <====== BUG?
}
[download]

In my eyes, the undef; should be replaced by a plain return; to prevent getting a (true!) list with one value (of undef), which in scalar context is true, e.g.

D:\workspace> perl
D:\eclipse\workspace\BDC\lib> perl
use strict;
use warnings;
use Data::Dumper;
use List::Util;

my @list = 1..20;
my @first = List::Util::first { $_ == 21 } @list;
print Dumper( \@first );
if( @first ) {
  print "In scalar-context: true\n";
}
^D
$VAR1 = [
          undef
        ];
In scalar-context: true
[download]

D:\workspace>perl -MList::Util -le "print $List::Util::VERSION"
1.19
[download]

Well, in the POD it is clearly stated that the first element is returned or undef - if not found. But since the syntax looks very similar to map and grep and the like, it might cause trouble without need if someone uses a list instead of a scalar to accept the result.

What do you think about?