From 7005a9a42fdf46fbd6925c995300c01ae56995f9 Mon Sep 17 00:00:00 2001
From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Fri, 3 Oct 2008 03:39:52 +0000
Subject: [PATCH] - Adjustment to Session's post-flush accounting of newly
 "clean" objects to better protect against operating on objects as they're
 asynchronously gc'ed. [ticket:1182]

---
 CHANGES                       |  4 ++++
 lib/sqlalchemy/orm/session.py | 23 ++++++++++++-----------
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/CHANGES b/CHANGES
index c129c06529..c5ddb12301 100644
--- a/CHANGES
+++ b/CHANGES
@@ -46,6 +46,10 @@ CHANGES
       
     - Some adjustments to Session.identity_map's weak referencing
       behavior to reduce asynchronous GC side effects.
+    
+    - Adjustment to Session's post-flush accounting of newly
+      "clean" objects to better protect against operating on
+      objects as they're asynchronously gc'ed. [ticket:1182]
       
 - sql
     - column.in_(someselect) can now be used as a columns-clause
diff --git a/lib/sqlalchemy/orm/session.py b/lib/sqlalchemy/orm/session.py
index d4d512034e..387f5a28d6 100644
--- a/lib/sqlalchemy/orm/session.py
+++ b/lib/sqlalchemy/orm/session.py
@@ -1026,19 +1026,20 @@ class Session(object):
 
     def _register_newly_persistent(self, state):
         mapper = _state_mapper(state)
-        instance_key = mapper._identity_key_from_state(state)
 
-        if state.key is None:
-            state.key = instance_key
-        elif state.key != instance_key:
-            # primary key switch
-            self.identity_map.remove(state)
-            state.key = instance_key
-
-        obj = state.obj()
         # prevent against last minute dereferences of the object
-        # TODO: identify a code path where state.obj() is None
+        obj = state.obj()
         if obj is not None:
+
+            instance_key = mapper._identity_key_from_state(state)
+
+            if state.key is None:
+                state.key = instance_key
+            elif state.key != instance_key:
+                # primary key switch
+                self.identity_map.remove(state)
+                state.key = instance_key
+
             if state.key in self.identity_map and not self.identity_map.contains_state(state):
                 self.identity_map.remove_key(state.key)
             self.identity_map.add(state)
@@ -1435,7 +1436,7 @@ class Session(object):
         except:
             transaction.rollback()
             raise
-
+        
         flush_context.finalize_flush_changes()
 
         if not objects:
-- 
2.47.3