storea is asynchronous and was, therefore, never supposed to return or

raise an exception. It should catch and serialize exceptions raised by
the underlying storage, however, unpicklable exceptions could cause it
to accidentally raise an exception. We now pickle exceptions more
carefully, catching and handling pickling errors.

src/ZEO/StorageServer.py

@@ -83,7 +83,7 @@
 # 
 ##############################################################################
 
-__version__ = "$Revision: 1.16 $"[11:-2]
+__version__ = "$Revision: 1.17 $"[11:-2]
 
 import asyncore, socket, string, sys, cPickle, os
 from smac import SizedMessageAsyncConnection
@@ -418,8 +418,16 @@ class Connection(SizedMessageAsyncConnection):
         else:
             if serial != '\0\0\0\0\0\0\0\0':
                 self.__invalidated.append((oid, version))
-                
-        self.message_output('s'+dump((oid,newserial), 1))
+
+        try: r=dump((oid,newserial), 1)
+        except:
+            # We got a pickling error, must be because the
+            # newserial is an unpicklable exception.
+            r=StorageServerError("Couldn't pickle exception %s" % `newserial`)
+            dump('',1) # clear pickler
+            r=dump((oid, r),1)
+            
+        self.message_output('s'+r)
         return _noreturn
 
     def vote(self, id):