[Zodb-checkins] CVS: ZODB3 - NEWS.txt:1.33.6.79

[Tim Peters]

Update of /cvs-repository/ZODB3
In directory cvs.zope.org:/tmp/cvs-serv26821

Modified Files:
      Tag: Zope-2_7-branch
	NEWS.txt 
Log Message:
tpc_finish:  Repair longstanding bugs in subtransaction commit.

Jim (Fulton) discovered this in ZODB 3.4's code, while implementing
savepoint/rollback.  Same bugs have been there at least since ZODB 3.1.


=== ZODB3/NEWS.txt 1.33.6.78 => 1.33.6.79 ===
--- ZODB3/NEWS.txt:1.33.6.78	Wed Apr 27 14:59:48 2005
+++ ZODB3/NEWS.txt	Mon May  2 16:30:26 2005
@@ -1,3 +1,27 @@
+What's new in ZODB3 3.2.9?
+==========================
+Release date: DD-MMM-2005
+
+Subtransactions
+---------------
+
+Doing a subtransaction commit erroneously processed invalidations, which could
+lead to an inconsistent view of the database.  For example, let T be the 
+transaction of which the subtransaction commit was a part.  If T read a 
+persistent object O's state before the subtransaction commit, did not commit 
+new state of its own for O during its subtransaction commit, and O was 
+modified before the subtransaction commit by a different transaction, then the
+subtransaction commit processed an invalidation for O, and the state T read 
+for O originally was discarded in T.  If T went on to access O again, it saw 
+the newly committed (by a different transaction) state for O::
+
+    o_attr = O.some_attribute
+    get_transaction().commit(True)
+    assert o_attr == O.some_attribute
+
+could fail, and despite that T never modifed O.
+
+
 What's new in ZODB3 3.2.8?
 ==========================
 Release date: 27-Apr-2005