undefined array key error in locale_field_node_form_submit() when moving fields in a hook_form_alter() #6918
Description
Description of the bug
I am using hook_form_alter() to move some fields around the form array, as I need some ajax functionality. My code moves a field from $form['field_name'] to $form['ajax_wrapper']['field_name']. Then just unsets the original $form['field_name'].
locale_field_node_form_submit() function, in locale.module, has this code on line 238:
$previous_langcode = $form[$field_name]['#language'];
which triggers the error because there is not field_name as key of the $form array, as I just unset it.
Besides this error, everything else works as expected. No other backdrop's code complains about a missing key. My ajax is also working.
Using $form['field_name'] = array('#language' => NULL); instead of unsetting the field_name array, in my code, fixes the problem, or even using $form['field_proveidor']['#access'] = FALSE; solves the problem, and the ajax is still working fine.
However, I wonder if it wouldn't be better that locale module just checked the existence of the field_name key before using it. Something like this worked for me:
$previous_langcode = isset($form[$field_name]) ? $form[$field_name]['#language']: '';
Would that be a right approach to address this issue? I am aware that my need is very specific, but, still, the locale module is using a value without any prior checking. Shouldn't this be addressed?