Merge "dont use uninstrument event to dispose registry entry"

5 files changed, 14 insertions, 9 deletions

diff --git a/lib/sqlalchemy/orm/__init__.py b/lib/sqlalchemy/orm/__init__.py
index 13626fb21..7f2c61a05 100644
--- a/lib/sqlalchemy/orm/__init__.py
+++ b/lib/sqlalchemy/orm/__init__.py
@@ -253,8 +253,13 @@ def clear_mappers():
     """
     with mapperlib._CONFIGURE_MUTEX:
         while _mapper_registry:
-            mapper, b = _mapper_registry.popitem()
-            mapper.dispose()
+            try:
+                mapper, b = _mapper_registry.popitem()
+            except KeyError:
+                # weak registry, item could have been collected
+                pass
+            else:
+                mapper.dispose()
 
 
 joinedload = strategy_options.joinedload._unbound_fn
diff --git a/lib/sqlalchemy/orm/decl_api.py b/lib/sqlalchemy/orm/decl_api.py
index 41cc88112..70fffa295 100644
--- a/lib/sqlalchemy/orm/decl_api.py
+++ b/lib/sqlalchemy/orm/decl_api.py
@@ -454,7 +454,7 @@ class registry(object):
         self.metadata = lcl_metadata
         self.constructor = constructor
 
-    def _dispose_declarative_artifacts(self, cls):
+    def _dispose_cls(self, cls):
         clsregistry.remove_class(cls.__name__, cls, self._class_registry)
 
     def generate_base(
diff --git a/lib/sqlalchemy/orm/decl_base.py b/lib/sqlalchemy/orm/decl_base.py
index 644e4aff6..0e0c79b1f 100644
--- a/lib/sqlalchemy/orm/decl_base.py
+++ b/lib/sqlalchemy/orm/decl_base.py
@@ -189,12 +189,6 @@ class _MapperConfig(object):
             init_method=registry.constructor,
         )
 
-        event.listen(
-            cls_,
-            "class_uninstrument",
-            registry._dispose_declarative_artifacts,
-        )
-
     def set_cls_attribute(self, attrname, value):
 
         manager = instrumentation.manager_of_class(self.cls)
diff --git a/lib/sqlalchemy/orm/events.py b/lib/sqlalchemy/orm/events.py
index 0349c445c..29a509cb9 100644
--- a/lib/sqlalchemy/orm/events.py
+++ b/lib/sqlalchemy/orm/events.py
@@ -67,6 +67,11 @@ class InstrumentationEvents(event.Events):
 
         def listen(target_cls, *arg):
             listen_cls = target()
+
+            # if weakref were collected, however this is not something
+            # that normally happens.   it was occurring during test teardown
+            # between mapper/registry/instrumentation_manager, however this
+            # interaction was changed to not rely upon the event system.
             if listen_cls is None:
                 return None
 
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 821c8a3c8..296ddf385 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1293,6 +1293,7 @@ class Mapper(
             and self.class_manager.is_mapped
             and self.class_manager.mapper is self
         ):
+            self.class_manager.registry._dispose_cls(self.class_)
             instrumentation.unregister_class(self.class_)
 
     def _configure_pks(self):