Ensure attribute keys used for bulk update pk set

Fixed bug in :meth:`.Session.bulk_update_mappings` where an alternate-named
primary key attribute would not track properly into the UPDATE statement.

Change-Id: I33e9140f45827772768fa548adcfeb4dbfc2208d
Fixes: #3849

2 files changed, 11 insertions, 1 deletions

diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 60848097c..87f2a24b0 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -2020,6 +2020,16 @@ class Mapper(InspectionAttr):
         )
 
     @_memoized_configured_property
+    def _pk_attr_keys_by_table(self):
+        return dict(
+            (
+                table,
+                frozenset([self._columntoproperty[col].key for col in pks])
+            )
+            for table, pks in self._pks_by_table.items()
+        )
+
+    @_memoized_configured_property
     def _server_default_cols(self):
         return dict(
             (
diff --git a/lib/sqlalchemy/orm/persistence.py b/lib/sqlalchemy/orm/persistence.py
index 2bc189c1d..bf51a2a83 100644
--- a/lib/sqlalchemy/orm/persistence.py
+++ b/lib/sqlalchemy/orm/persistence.py
@@ -522,7 +522,7 @@ def _collect_update_commands(
                 (propkey_to_col[propkey]._label, state_dict.get(propkey))
                 for propkey in
                 set(propkey_to_col).
-                intersection(mapper._pk_keys_by_table[table])
+                intersection(mapper._pk_attr_keys_by_table[table])
             )
         else:
             pk_params = {}