Backport code changes from aosabook#200

MichaelDiBernardo · MichaelDiBernardo · commit 3a1328275459 · 2016-04-09T10:07:42.000-04:00
diff --git a/cluster/cluster.markdown b/cluster/cluster.markdown
@@ -468,7 +468,7 @@ class Replica(Role):
         self.execute_fn = execute_fn
         self.state = state
         self.slot = slot
-        self.decisions = decisions.copy()
+        self.decisions = decisions
         self.peers = peers
         self.proposals = {}
         # next slot num for a proposal (may lead slot)
@@ -983,7 +983,9 @@ class Network(object):
 
     def send(self, sender, destinations, message):
         sender.logger.debug("sending %s to %s", message, destinations)
-        for dest in (d for d in destinations if d in self.nodes):
+        # avoid aliasing by making a closure containing distinct deep copy of
+        # message for each dest
+        def sendto(dest, message):
             if dest == sender.address:
                 # reliably deliver local messages with no delay
                 self.set_timer(sender.address, 0,  
@@ -994,6 +996,8 @@ class Network(object):
                 self.set_timer(dest, delay, 
                                functools.partial(self.nodes[dest].receive, 
                                                  sender.address, message))
+        for dest in (d for d in destinations if d in self.nodes):
+            sendto(dest, copy.deepcopy(message))
     
 ```
 
