Fatal error in case of invalid value submitted

Works for me! Marking RTBC! Thank you, ilya.no!

I don't think the solution is to pass the value as is if it is wrong, since we do actually need to deal with the fact that the IP address is not a properly formatted range (or if someone had the gall to try to enter a range using asterisks).

The validateIpAddressElement function in IpAddressWidgetBase.php actually depends on there being an exception to validate the form field:

   // Instantiate our IP, will throw \Exception if invalid.
    try {
      $ip_address = new IpAddress($value);
    }
    catch (\Exception $e) {
      // Make error messages a bit more relevant.
      if ($settings['allow_range']) {
        $form_state->setError($element, t('Invalid IP or range.'));
      }
      else {
        $form_state->setError($element, t('Invalid IP.'));
      }
      return;
    }

The question is why the IpAddress function isn't being constructed within that try catch in the validation function on form submission.

As an alternative solution, this patch will change it so we only run the massageFormValues logic if the form has passed validation.

fixed by commit a29b74c under #3247108 — note that @ilya.no proposed the same fix in patch #2 here two years earlier; sickness29's later MR also carried the try/catch and was what ultimately landed.