Merge "Don't expire "deferred" attributes in make_transient_to_detached"

doc/build/changelog/unreleased_12/4084.rst

@@ -0,0 +1,8 @@
+.. change::
+    :tags: bug, orm
+    :tickets: 4084
+
+    Fixed issue where the :func:`.make_transient_to_detached` function
+    would expire all attributes on the target object, including "deferred"
+    attributes, which has the effect of the attribute being undeferred
+    for the next refesh, causing an unexpected load of the attribute.

lib/sqlalchemy/orm/session.py

@@ -3037,7 +3037,7 @@ def make_transient_to_detached(instance):
     if state._deleted:
         del state._deleted
     state._commit_all(state.dict)
-    state._expire_attributes(state.dict, state.unloaded)
+    state._expire_attributes(state.dict, state.unloaded_expirable)
 
 
 def object_session(instance):

lib/sqlalchemy/orm/state.py

@@ -610,6 +610,7 @@ class InstanceState(interfaces.InspectionAttr):
     def unmodified_intersection(self, keys):
         """Return self.unmodified.intersection(keys)."""
 
+
         return set(keys).intersection(self.manager).\
             difference(self.committed_state)
 
@@ -625,6 +626,18 @@ class InstanceState(interfaces.InspectionAttr):
             difference(self.committed_state).\
             difference(self.dict)
 
+    @property
+    def unloaded_expirable(self):
+        """Return the set of keys which do not have a loaded value.
+
+        This includes expired attributes and any other attribute that
+        was never populated or modified.
+
+        """
+        return self.unloaded.intersection(
+            attr for attr in self.manager
+            if self.manager[attr].impl.expire_missing)
+
     @property
     def _unloaded_non_object(self):
         return self.unloaded.intersection(

test/orm/test_expire.py

@@ -13,6 +13,7 @@ from sqlalchemy.orm import mapper, relationship, create_session, \
 from sqlalchemy.testing import fixtures
 from test.orm import _fixtures
 from sqlalchemy.sql import select
+from sqlalchemy.orm import make_transient_to_detached
 
 
 class ExpireTest(_fixtures.FixtureTest):
@@ -1035,6 +1036,46 @@ class ExpireTest(_fixtures.FixtureTest):
             .expired_attributes
         assert 'addresses' not in attributes.instance_state(u1).callables
 
+    def test_deferred_expire_w_transient_to_detached(self):
+        orders, Order = self.tables.orders, self.classes.Order
+        mapper(Order, orders, properties={
+            "description": deferred(orders.c.description)
+        })
+
+        s = Session()
+        item = Order(id=1)
+
+        make_transient_to_detached(item)
+        s.add(item)
+        item.isopen
+        assert 'description' not in item.__dict__
+
+    def test_deferred_expire_normally(self):
+        orders, Order = self.tables.orders, self.classes.Order
+        mapper(Order, orders, properties={
+            "description": deferred(orders.c.description)
+        })
+
+        s = Session()
+
+        item = s.query(Order).first()
+        s.expire(item)
+        item.isopen
+        assert 'description' not in item.__dict__
+
+    def test_deferred_expire_explicit_attrs(self):
+        orders, Order = self.tables.orders, self.classes.Order
+        mapper(Order, orders, properties={
+            "description": deferred(orders.c.description)
+        })
+
+        s = Session()
+
+        item = s.query(Order).first()
+        s.expire(item, ['isopen', 'description'])
+        item.isopen
+        assert 'description' in item.__dict__
+
 
 class PolymorphicExpireTest(fixtures.MappedTest):
     run_inserts = 'once'