11. How to perform EntityFieldQuery for entities with more than one OG audience field

This is here to document an alternative way to perform EntityFieldQuery for entities with more than one OG audience field.

• Bug description: og_query_og_membership_alter is defective and affects EntityFieldQuery
• Related D7 issue: Cannot make an EntityFieldQuery using two OG fields as condition
• Solution based on Comment 12 of the D7 issue

Instead of:

    $query = new EntityFieldQuery();
    $result_will_fail = $query
      ->entityCondition('entity_type', 'node')
      ->propertyCondition('type', $node->type)
      ->fieldCondition('og_group1_ref', 'target_id', $group1->nid)
      ->fieldCondition('og_group2_ref', 'target_id', $group2->nid)
      ->execute();

Use:

    $query = new EntityFieldQuery();
    $result1 = $query
      ->entityCondition('entity_type', 'node')
      ->propertyCondition('type', $node->type)
      ->fieldCondition('og_group1_ref', 'target_id', $group1->nid)
      ->execute();

    $query = new EntityFieldQuery();
    $result2 = $query
      ->entityCondition('entity_type', 'node')
      ->propertyCondition('type', $node->type)
      ->fieldCondition('og_group2_ref', 'target_id', $group2->nid)
      ->execute();

    $result_ids = array_intersect(array_keys($result1['node']), array_keys($result2['node']));

Of course, be sure to check that $result1['node'] and $result2['node'] are set before the array_intersect.