detected error in assert state machine, regarding receiving preferred assert

tree/assert_.py

@@ -41,7 +41,7 @@ class AssertStateABC(metaclass=ABCMeta):
 
     @staticmethod
     @abstractmethod
-    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric):
+    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric, is_metric_equal):
         """
         Receive Preferred Assert OR State Refresh
 
@@ -134,33 +134,34 @@ class NoInfoState(AssertStateABC):
         """
         @type interface: TreeInterface
         """
+        interface.assert_logger.debug('receivedDataFromDownstreamIf, NI -> W')
+
         interface.set_assert_winner_metric(interface.my_assert_metric())
         interface.set_assert_state(AssertState.Winner)
 
         NoInfoState._sendAssert_setAT(interface)
 
-        #print('receivedDataFromDownstreamIf, NI -> W')
-        interface.assert_logger.debug('receivedDataFromDownstreamIf, NI -> W')
-
     @staticmethod
     def receivedInferiorMetricFromWinner(interface: "TreeInterfaceDownstream"):
         assert False, "this should never ocurr"
 
     @staticmethod
     def receivedInferiorMetricFromNonWinner_couldAssertIsTrue(interface: "TreeInterfaceDownstream"):
+        interface.assert_logger.debug('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, NI -> W')
+
         interface.set_assert_winner_metric(interface.my_assert_metric())
         interface.set_assert_state(AssertState.Winner)
 
         NoInfoState._sendAssert_setAT(interface)
 
-        #print('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, NI -> W')
-        interface.assert_logger.debug('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, NI -> W')
-
     @staticmethod
-    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric):
+    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric, is_metric_equal):
         '''
         @type interface: TreeInterface
         '''
+        if is_metric_equal:
+            return
+        interface.assert_logger.debug('receivedPreferedMetric, NI -> L')
         state_refresh_interval = better_metric.state_refresh_interval
         if state_refresh_interval is None:
             # event caused by Assert Msg
@@ -177,9 +178,6 @@ class NoInfoState(AssertStateABC):
         if interface.could_assert():
             interface.send_prune(holdtime=assert_timer_value)
 
-        #print('receivedPreferedMetric, NI -> L')
-        interface.assert_logger.debug('receivedPreferedMetric, NI -> L')
-
     @staticmethod
     def sendStateRefresh(interface: "TreeInterfaceDownstream", time):
         pass
@@ -190,12 +188,10 @@ class NoInfoState(AssertStateABC):
 
     @staticmethod
     def couldAssertIsNowFalse(interface: "TreeInterfaceDownstream"):
-        #print('couldAssertIsNowFalse, NI -> NI')
         interface.assert_logger.debug('couldAssertIsNowFalse, NI -> NI')
 
     @staticmethod
     def couldAssertIsNowTrue(interface: "TreeInterfaceDownstream"):
-        #print('couldAssertIsNowTrue, NI -> NI')
         interface.assert_logger.debug('couldAssertIsNowTrue, NI -> NI')
 
     @staticmethod
@@ -204,7 +200,6 @@ class NoInfoState(AssertStateABC):
 
     @staticmethod
     def receivedPruneOrJoinOrGraft(interface: "TreeInterfaceDownstream"):
-        #print('receivedPruneOrJoinOrGraft, NI -> NI')
         interface.assert_logger.debug('receivedPruneOrJoinOrGraft, NI -> NI')
 
     def __str__(self) -> str:
@@ -224,10 +219,8 @@ class WinnerState(AssertStateABC):
         """
         @type interface: TreeInterface
         """
-        WinnerState._sendAssert_setAT(interface)
-
-        #print('receivedDataFromDownstreamIf, W -> W')
         interface.assert_logger.debug('receivedDataFromDownstreamIf, W -> W')
+        WinnerState._sendAssert_setAT(interface)
 
     @staticmethod
     def receivedInferiorMetricFromWinner(interface: "TreeInterfaceDownstream"):
@@ -235,16 +228,17 @@ class WinnerState(AssertStateABC):
 
     @staticmethod
     def receivedInferiorMetricFromNonWinner_couldAssertIsTrue(interface: "TreeInterfaceDownstream"):
-        WinnerState._sendAssert_setAT(interface)
-
-        #print('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, W -> W')
         interface.assert_logger.debug('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, W -> W')
+        WinnerState._sendAssert_setAT(interface)
 
     @staticmethod
-    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric):
+    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric, is_metric_equal):
         '''
         @type better_metric: AssertMetric
         '''
+        if is_metric_equal:
+            return
+        interface.assert_logger.debug('receivedPreferedMetric, W -> L')
         state_refresh_interval = better_metric.state_refresh_interval
         if state_refresh_interval is None:
             # event caused by AssertMsg
@@ -258,8 +252,6 @@ class WinnerState(AssertStateABC):
         interface.set_assert_state(AssertState.Loser)
 
         interface.send_prune(holdtime=assert_timer_value)
-        #print('receivedPreferedMetric, W -> L')
-        interface.assert_logger.debug('receivedPreferedMetric, W -> L')
 
     @staticmethod
     def sendStateRefresh(interface: "TreeInterfaceDownstream", state_refresh_interval):
@@ -267,14 +259,13 @@ class WinnerState(AssertStateABC):
 
     @staticmethod
     def assertTimerExpires(interface: "TreeInterfaceDownstream"):
+        interface.assert_logger.debug('assertTimerExpires, W -> NI')
         interface.set_assert_winner_metric(AssertMetric.infinite_assert_metric())
         interface.set_assert_state(AssertState.NoInfo)
 
-        #print('assertTimerExpires, W -> NI')
-        interface.assert_logger.debug('assertTimerExpires, W -> NI')
-
     @staticmethod
     def couldAssertIsNowFalse(interface: "TreeInterfaceDownstream"):
+        interface.assert_logger.debug('couldAssertIsNowFalse, W -> NI')
         interface.send_assert_cancel()
 
         interface.clear_assert_timer()
@@ -282,9 +273,6 @@ class WinnerState(AssertStateABC):
         interface.set_assert_winner_metric(AssertMetric.infinite_assert_metric())
         interface.set_assert_state(AssertState.NoInfo)
 
-        #print('couldAssertIsNowFalse, W -> NI')
-        interface.assert_logger.debug('couldAssertIsNowFalse, W -> NI')
-
     @staticmethod
     def couldAssertIsNowTrue(interface: "TreeInterfaceDownstream"):
         assert False, "this should never ocurr"
@@ -314,26 +302,23 @@ class LoserState(AssertStateABC):
         """
         @type interface: TreeInterface
         """
-        #print('receivedDataFromDownstreamIf, L -> L')
         interface.assert_logger.debug('receivedDataFromDownstreamIf, L -> L')
 
     @staticmethod
     def receivedInferiorMetricFromWinner(interface: "TreeInterfaceDownstream"):
-        LoserState._to_NoInfo(interface)
-
-        #print('receivedInferiorMetricFromWinner, L -> NI')
         interface.assert_logger.debug('receivedInferiorMetricFromWinner, L -> NI')
+        LoserState._to_NoInfo(interface)
 
     @staticmethod
     def receivedInferiorMetricFromNonWinner_couldAssertIsTrue(interface: "TreeInterfaceDownstream"):
-        #print('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, L -> L')
         interface.assert_logger.debug('receivedInferiorMetricFromNonWinner_couldAssertIsTrue, L -> L')
 
     @staticmethod
-    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric):
+    def receivedPreferedMetric(interface: "TreeInterfaceDownstream", better_metric, is_metric_equal):
         '''
         @type better_metric: AssertMetric
         '''
+        interface.assert_logger.debug('receivedPreferedMetric, L -> L')
         state_refresh_interval = better_metric.state_refresh_interval
         if state_refresh_interval is None:
             assert_timer_value = pim_globals.ASSERT_TIME
@@ -344,47 +329,37 @@ class LoserState(AssertStateABC):
         interface.set_assert_winner_metric(better_metric)
         interface.set_assert_state(AssertState.Loser)
 
-        if interface.could_assert():
+        if not is_metric_equal and interface.could_assert():
             interface.send_prune(holdtime=assert_timer_value)
 
-        #print('receivedPreferedMetric, L -> L')
-        interface.assert_logger.debug('receivedPreferedMetric, L -> L')
-
     @staticmethod
     def sendStateRefresh(interface: "TreeInterfaceDownstream", time):
         assert False, "this should never ocurr"
 
     @staticmethod
     def assertTimerExpires(interface: "TreeInterfaceDownstream"):
-        LoserState._to_NoInfo(interface)
-        #print('assertTimerExpires, L -> NI')
         interface.assert_logger.debug('assertTimerExpires, L -> NI')
+        LoserState._to_NoInfo(interface)
 
     @staticmethod
     def couldAssertIsNowFalse(interface: "TreeInterfaceDownstream"):
-        LoserState._to_NoInfo(interface)
-        #print('couldAssertIsNowFalse, L -> NI')
         interface.assert_logger.debug('couldAssertIsNowFalse, L -> NI')
+        LoserState._to_NoInfo(interface)
 
     @staticmethod
     def couldAssertIsNowTrue(interface: "TreeInterfaceDownstream"):
-        LoserState._to_NoInfo(interface)
-        #print('couldAssertIsNowTrue, L -> NI')
         interface.assert_logger.debug('couldAssertIsNowTrue, L -> NI')
+        LoserState._to_NoInfo(interface)
 
     @staticmethod
     def winnerLivelinessTimerExpires(interface: "TreeInterfaceDownstream"):
-        LoserState._to_NoInfo(interface)
-
-        #print('winnerLivelinessTimerExpires, L -> NI')
         interface.assert_logger.debug('winnerLivelinessTimerExpires, L -> NI')
+        LoserState._to_NoInfo(interface)
 
     @staticmethod
     def receivedPruneOrJoinOrGraft(interface: "TreeInterfaceDownstream"):
-        interface.send_assert()
-
-        #print('receivedPruneOrJoinOrGraft, L -> L')
         interface.assert_logger.debug('receivedPruneOrJoinOrGraft, L -> L')
+        interface.send_assert()
 
     @staticmethod
     def _to_NoInfo(interface: "TreeInterfaceDownstream"):

tree/metric.py

@@ -22,6 +22,10 @@ class AssertMetric(object):
     def is_worse(self, other):
         return not self.is_better_than(other)
 
+    def equal_metric(self, other):
+        return self.metric_preference == other.metric_preference and self.metric_preference == other.metric_preference \
+               and self.ip_address == other.ip_address
+
     @staticmethod
     def infinite_assert_metric():
         '''

tree/tree_interface.py

@@ -114,17 +114,18 @@ class TreeInterface(metaclass=ABCMeta):
         pass
 
     def recv_assert_msg(self, received_metric: AssertMetric):
-        if self.my_assert_metric().is_better_than(received_metric):
-            # received inferior assert
-            if self._assert_winner_metric.ip_address == received_metric.ip_address:
-                # received from assert winner
+        if self._assert_winner_metric.is_better_than(received_metric) and \
+                self._assert_winner_metric.ip_address == received_metric.ip_address:
+            # received inferior assert from Assert Winner
             self._assert_state.receivedInferiorMetricFromWinner(self)
-            elif self.could_assert():
-                # received from non assert winner and could_assert
+        elif self.my_assert_metric().is_better_than(received_metric) and self.could_assert():
+            # received inferior assert from non assert winner and could_assert
             self._assert_state.receivedInferiorMetricFromNonWinner_couldAssertIsTrue(self)
-        elif received_metric.is_better_than(self._assert_winner_metric):
+        elif received_metric.is_better_than(self._assert_winner_metric) or \
+                received_metric.equal_metric(self._assert_winner_metric):
             #received preferred assert
-            self._assert_state.receivedPreferedMetric(self, received_metric)
+            equal_metric = received_metric.equal_metric(self._assert_winner_metric)
+            self._assert_state.receivedPreferedMetric(self, received_metric, equal_metric)
 
     def recv_prune_msg(self, upstream_neighbor_address, holdtime):
         if upstream_neighbor_address == self.get_ip():