Ticket #34894: patch_34894.diff

django/db/models/sql/query.py

@@ -988 +988 @@
         }
 
         # 2. Rename the alias in the internal table/alias datastructures.
-        for old_alias, new_alias in change_map.items():
-            if old_alias not in self.alias_map:
+        # - The order of insertion in alias_map has great importance for
+        #   future iterations, so we need to rebuild it in the original order.
+        # - alias_data must be relabeled if it contains a change to do in
+        #   alias_data.parent_alias, even if its alias does not change.
+        # - Cached property base_table need to change if necessary.
+        base_table_cached = self.__dict__.get("base_table", None)
+        old_alias_map, self.alias_map = self.alias_map, {}
+        for old_alias, alias_data in old_alias_map.items():
+            if old_alias not in change_map:
+                self.alias_map[old_alias] = (
+                    alias_data.relabeled_clone(change_map)
+                    if alias_data.parent_alias in change_map
+                    else alias_data
+                )
                 continue
-            alias_data = self.alias_map[old_alias].relabeled_clone(change_map)
-            self.alias_map[new_alias] = alias_data
+            new_alias = change_map[old_alias]
+            if old_alias == base_table_cached:
+                self.__dict__["base_table"] = new_alias
+            self.alias_map[new_alias] = alias_data.relabeled_clone(change_map)
             self.alias_refcount[new_alias] = self.alias_refcount[old_alias]
             del self.alias_refcount[old_alias]
-            del self.alias_map[old_alias]
 
             table_aliases = self.table_map[alias_data.table_name]
             for pos, alias in enumerate(table_aliases):

tests/queries/test_query.py

@@ -89 +89 @@
         self.assertIsNone(lookup.lhs.lhs.alias)
         self.assertEqual(lookup.lhs.lhs.target, Author._meta.get_field("name"))
 
+    def test_change_aliases_alias_map_order(self):
+        query = Query(Item)
+        # force to create a join between Item and Author
+        query.add_q(Q(creator__num__gt=2))
+        # force to initialize all joins and caches
+        sql = str(query)
+        order = [
+            "item_alias" if alias == Item._meta.db_table else alias
+            for alias in list(query.alias_map)
+        ]
+        query.change_aliases({
+            Item._meta.db_table: "item_alias",
+        })
+        self.assertEqual(list(query.alias_map), order)
+
+    def test_change_aliases_nested_joins(self):
+        query = Query(Item)
+        # force to create a join between Item and Author
+        query.add_q(Q(creator__num__gt=2))
+        # force to initialize all joins and caches
+        sql = str(query)
+        self.assertEqual(query.alias_map[Author._meta.db_table].parent_alias, Item._meta.db_table)
+        query.change_aliases({
+            Item._meta.db_table: "item_alias",
+        })
+        self.assertEqual(query.alias_map[Author._meta.db_table].parent_alias, "item_alias")
+
+    def test_change_aliases_base_table(self):
+        query = Query(Item)
+        # force to create a join between Item and Author
+        query.add_q(Q(creator__num__gt=2))
+        # force to initialize all joins and caches
+        sql = str(query)
+        self.assertEqual(query.base_table, Item._meta.db_table)
+        query.change_aliases({
+            Item._meta.db_table: "item_alias",
+        })
+        self.assertEqual(query.base_table, "item_alias")
+
     def test_negated_nullable(self):
         query = Query(Item)
         where = query.build_where(~Q(modified__lt=datetime(2017, 1, 1)))