Field Translation: Possible loss of data

This is a follow up to #1414554: Translation set not being saved properly on the product entity which fixed part of the problem.

Not fixed by the above patch is the problem of translatable fields content being lost when creating(!) a product in a language, other than site-default.

After updating to 1.2 I've revisited the issue and have indentified another culprit in commerce_product_ui.module (line 528) :

-- start reading from the LAST comment (bottom up) --

/**
 * Submit callback for commerce_product_ui_product_form().
 *
 * Checks if translation is enabled for the product and handles language changes.
 * Since this handler may change the language of submitted form values it should
 * be the first submit handler called.
 *
 * @see commerce_product_ui_form_commerce_product_ui_product_form_alter()
 */
function commerce_product_ui_product_form_translation_submit($form, &$form_state) {
  // Get an array of available languages.
  $available_languages = field_content_languages();
  list(, , $bundle) = entity_extract_ids('commerce_product', $form_state['commerce_product']);

  foreach (field_info_instances('commerce_product', $bundle) as $instance) {
    $field_name = $instance['field_name'];
    $field = field_info_field($field_name);
    $previous_language = $form[$field_name]['#language'];

    // Handle a possible language change; new language values are inserted and
    // the previous values are deleted.
    if ($field['translatable'] && $previous_language != $form_state['values']['language']) {
          $form_state['values'][$field_name][$form_state['values']['language']] = $form_state['commerce_product']->{$field_name}[$previous_language]; 


/* 
the above line is causing the problem, as the object $form_state['commerce_product']->{$field_name} is not necessarily available, thus setting the value to 'null'.
Replacing it with the following assignment solves the problem of translatable fields ending up empty:

$form_state['values'][$field_name][$form_state['values']['language']] = $form_state['values'][$field_name][$previous_language];
*/



      $form_state['values'][$field_name][$previous_language] = array();
    }
  }
}

Since I dont know if it is generally save to rely on the values array, rather than the $form_state['commerce_product']->{$field_name} attribute, I've wrapped the whole thing in a conditional, to only use the values array when $form_state['commerce_product']->{$field_name} is not set (which happens to be the case for all translatable fields on my product).

It works well for me, but I can't vouch for this making sense in broader terms.
So if someone with a better understanding of this stuff would like to review, I'd be most happy.