CRM-13807 - Add comments and null test

api/v3/utils.php

@@ -307,8 +307,12 @@ function _civicrm_api3_get_DAO($name) {
  */
 function _civicrm_api3_get_BAO($name) {
   $dao = _civicrm_api3_get_DAO($name);
+  if (!$dao) {
+    return NULL;
+  }
   $bao = str_replace("DAO", "BAO", $dao);
   $file = strtr($bao, '_', '/') . '.php';
+  // Check if this entity actually has a BAO. Fall back on the DAO if not.
   return stream_resolve_include_path($file) ? $bao : $dao;
 }
 

tests/phpunit/api/v3/UtilsTest.php

@@ -201,6 +201,8 @@ class api_v3_UtilsTest extends CiviUnitTestCase {
       'Household' => 'CRM_Contact_BAO_Contact',
       // Note this one DOES NOT have a BAO so we expect to fall back on returning the DAO
       'mailing_group' => 'CRM_Mailing_DAO_MailingGroup',
+      // Make sure we get null back with nonexistant entities
+      'civicrm_this_does_not_exist' => NULL,
     );
     foreach ($params as $input => $expected) {
       $result = _civicrm_api3_get_BAO($input);