There is a misunderstanding of $mech->success - this method only reflects whether the last HTTP response from the server is considered an error or not. It does not reflect whether the last operation on $mech was successful or not. Error checking is usually done by die by WWW::Mechanize::Chrome.

I haven't run your code, but the log output suggests that the form you're looking at has no name:

  say $mech->current_form->{name};    # ??
  # Use of uninitialized value in say at ./5.pluto.pl line 55.
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The form is not great, because it really contains three fields with the same name date, so you will have to fetch the individual fields and explicitly set them:

# largely untested
my @date_fields = $mech->selector('.//*[@name="date"]', node => $self-
+>current_form );
$mech->set_field( $date_fields[1] => $guess );
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In the next version, I'll actually implement the arrayref form of ->set_fields() for values of index larger than one :) But that means breaking my (incompatible) API to restore the WWW::Mechanize API so I'll have to look carefully there.

 $mech->set_fields( $name => [ 'foo', 2 ] );
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