Domain Access & Unique Field

I could make it on rc1 by altering a bit the module with this logic in unique_field_match_value():

  $efq->addTag('unique_field_match');
  if (isset($entity)) { //entity has to be passed as a new argument
    $efq->addMetadata('entity', $entity);
  }

This allows me to do that in my custom module:

/**
 * Implements hook_query_TAG_NAME_alter().
 */
function my_module_query_unique_field_match_alter(QueryAlterableInterface $query) {
  if (module_exists('domain_source')) {
    $entity = $query->getMetaData('entity');
    $base = $query->alterMetaData['base_table'];
    foreach($query->getTables() as $alias => $info) {
      if ($info['table'] == $base) {
        $base_alias = $info['alias'];
        break;
      }
    }
    if (isset($base_alias) && isset($entity->domain_source)) {
      $query->innerJoin('domain_source', 'ds', "%alias.nid = $base_alias.entity_id AND $base_alias.entity_type = 'node'");
      $query->condition('ds.domain_id', $entity->domain_source);
    }
  }
}

Here is a new patch against 7.x.

Unlinke the code in previous comment, I don't rely on the domain_source module which is optional.

Making a better patch, last one had an empty module_exists and no settings options.

Here is an improved patch with added options per content type for scoping.

Hmmm... testing this some more, the join does not actually seem to be executed. Weird, should work.

I'm closing it because the issue was created a long time ago without any further steps.

if you still need it then raise a new one.
thanks