- Patch #851748 by Stevel: weird logic in SelectQuery::addField().

includes/database/select.inc

@@ -1125,14 +1125,14 @@ public function addField($table_alias, $field, $alias = NULL) {
     }
 
     // If that's already in use, try the table name and field name.
-    if (!empty($this->tables[$alias])) {
+    if (!empty($this->fields[$alias])) {
       $alias = $table_alias . '_' . $field;
     }
 
     // If that is already used, just add a counter until we find an unused alias.
     $alias_candidate = $alias;
     $count = 2;
-    while (!empty($this->tables[$alias_candidate])) {
+    while (!empty($this->fields[$alias_candidate])) {
       $alias_candidate = $alias . '_' . $count++;
     }
     $alias = $alias_candidate;

modules/simpletest/tests/database_test.test

@@ -1543,6 +1543,16 @@ class DatabaseSelectTestCase extends DatabaseTestCase {
     sort($sorted_ids_second_set);
     $this->assertEqual($sorted_ids_second_set, $sorted_ids, t('After sorting the second random list, the result matches the sorted version of the first random list.'));
   }
+
+  /**
+   * Test that aliases are renamed when duplicates.
+   */
+  function testSelectDuplicateAlias() {
+    $query = db_select('test', 't');
+    $alias1 = $query->addField('t', 'name', 'the_alias');
+    $alias2 = $query->addField('t', 'age', 'the_alias');
+    $this->assertNotIdentical($alias1, $alias2, 'Duplicate aliases are renamed.');
+  }
 }
 
 /**