Server doesn't call serialnos for deleted objects

src/ZEO/ClientStorage.py

@@ -724,7 +724,10 @@ class ClientStorage(object):
         if tbuf.exception:
             raise tbuf.exception
 
+        if tbuf.serials:
             return list(tbuf.serials.items())
+        else:
+            return None
 
     def tpc_transaction(self):
         return self._transaction

src/ZEO/TransactionBuffer.py

@@ -83,7 +83,7 @@ class TransactionBuffer:
         for i in range(self.count):
             oid, data = unpickler.load()
             seen.add(oid)
-            yield oid, data, serials[oid] == ResolvedSerial
+            yield oid, data, serials.get(oid) == ResolvedSerial
 
         # We may have leftover serials because undo
         for oid, serial in serials.items():