[ZODB-Dev] rasing a ReadConflictError

[Michael Dunstan]

I'm working on a fix for Transience (with the help of Chris). There is 
a condition in the code in which it makes sense to raise a 
ReadConflictError from Transience itself. However it would seem that 
there is some light magic required to ensure that this will survive 
swallowing of the exception. How about putting the magic into the 
__init__ for ReadConflictError?

Here is a patch to try and illustrate what I'm going on about (oh yeah 
- this is Zope-2_7-branch):

Index: Connection.py
===================================================================
RCS file: /cvs-repository/Packages/ZODB/Attic/Connection.py,v
retrieving revision 1.98.4.7
diff -u -r1.98.4.7 Connection.py
--- Connection.py       27 Aug 2004 19:03:42 -0000      1.98.4.7
+++ Connection.py       31 Aug 2004 18:29:54 -0000
@@ -614,8 +614,6 @@
                      # Defer _p_independent() call until state is 
loaded.
                      return 1
                  else:
-                    self.getTransaction().register(obj)
-                    self._conflicts[obj._p_oid] = 1
                      raise ReadConflictError(object=obj)
              else:
                  return 0
Index: POSException.py
===================================================================
RCS file: /cvs-repository/Packages/ZODB/Attic/POSException.py,v
retrieving revision 1.20.4.3
diff -u -r1.20.4.3 POSException.py
--- POSException.py     27 Aug 2004 19:03:42 -0000      1.20.4.3
+++ POSException.py     31 Aug 2004 18:29:54 -0000
@@ -116,6 +116,8 @@
          ConflictError.__init__(self, message="database read conflict 
error",
                                 object=object)
          self.jar = object._p_jar
+        self.jar.getTransaction().register(object)
+        self.jar._conflicts[object._p_oid] = 1

      def ignore(self):
          self.jar._ignore_conflict(self.oid)