use strict;
use Data::Dumper;

while (<DATA>)
{
  chomp;
  my @rec;
  # was - foreach (split /"(.*,.*)"|,/) ...
  foreach (split /"((?:\\"|.)*?)"|,/) { push @rec, $_ if $_ }
  print Dumper(\@rec);
}

__DATA__
1,"Hello, world",This is good,2
121212,"Simpson, Bart",Springfield,"Roger"
121212,"2\" tape, \"white",springfield,"Roger"
121212,"Simpson \", Bart",Springfield,"Roger"

##</code><code>##

$VAR1 = [
          '1',
          'Hello, world',
          'This is good',
          '2'
        ];
$VAR1 = [
          '121212',
          'Simpson, Bart',
          'Springfield',
          'Roger'
        ];
$VAR1 = [
          '121212',
          '2\\" tape, \\"white',
          'springfield',
          'Roger'
        ];
$VAR1 = [
          '121212',
          'Simpson \\", Bart',
          'Springfield',
          'Roger'
        ];

##</code><code>##

use strict;
use Data::Dumper;

while (<DATA>)
{
    chomp;
    my @rec;
    foreach (split /"(.*?)(?:(?<!")"(?!")|(?<="")"(?!"))|,/)
        { s/""/"/g, push @rec, $_ if $_ }
    print Dumper(\@rec);
}

__DATA__
1,"Hello, world",This is good,2
121212,"Simpson, Bart",Springfield,"Roger"
121212,"2"" tape, ""white",springfield,"Roger"
121212,"Simpson "", Bart",Springfield,"Roger"
121212,"2""",springfield,"Roger"
##</code><code>##

$VAR1 = [
          '1',
          'Hello, world',
          'This is good',
          '2'
        ];
$VAR1 = [
          '121212',
          'Simpson, Bart',
          'Springfield',
          'Roger'
        ];
$VAR1 = [
          '121212',
          '2" tape, "white',
          'springfield',
          'Roger'
        ];
$VAR1 = [
          '121212',
          'Simpson ", Bart',
          'Springfield',
          'Roger'
        ];
$VAR1 = [
          '121212',
          '2"',
          'springfield',
          'Roger'
        ];