Fixed #34421 -- Fixed QuerySet.update() on querysets in descending order by annotations.

django/db/backends/mysql/features.py

@@ -108,6 +108,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
                 "update.tests.AdvancedTests."
                 "test_update_ordered_by_inline_m2m_annotation",
                 "update.tests.AdvancedTests.test_update_ordered_by_m2m_annotation",
+                "update.tests.AdvancedTests.test_update_ordered_by_m2m_annotation_desc",
             },
         }
         if self.connection.mysql_is_mariadb and (

django/db/models/query.py

@@ -1190,11 +1190,18 @@ class QuerySet(AltersData):
         # Inline annotations in order_by(), if possible.
         new_order_by = []
         for col in query.order_by:
-            if annotation := query.annotations.get(col):
+            alias = col
+            descending = False
+            if isinstance(alias, str) and alias.startswith("-"):
+                alias = alias.removeprefix("-")
+                descending = True
+            if annotation := query.annotations.get(alias):
                 if getattr(annotation, "contains_aggregate", False):
                     raise exceptions.FieldError(
                         f"Cannot update when ordering by an aggregate: {annotation}"
                     )
+                if descending:
+                    annotation = annotation.desc()
                 new_order_by.append(annotation)
             else:
                 new_order_by.append(col)