entity_translation_prepare_element() needlessly clones $form_state

entity_translation_prepare_element() currently clones the $form_state array and passes it to field_attach_form(). field_attach_form() will proxy to many other hooks within the system, some of whom alter the form_state for their later use. All of this is attached to the clone entity_translation_prepare_element() creates, but the $form_state is passed by reference to entity_translation_prepare_element() meaning Drupal intends to get whatever changes were made to form_state there back out for the rest of the system.

Inline Entity Form and perhaps other modules (paragraphs?, field_collection?) do EXACTLY this. IEF in particular adds settings to the form_state for later use during its submit. These values are missing as the code currently stands and cause a cascade of errors that ultimately result in a db error. Simply NOT cloning the $form_state and passing it as normal to field_attach_form() seems to solve this. Obviously some testing is probably in order, but I wanted to get more eyeballs on this, so please, take a look.

Eclipse