Exception in rerouting the Intents when there is a topology change

[NOTE: The ASCII topology below is readable only if you click on "edit"]

1. Switch topology before topology change:

Host2 ----- Switch11---------Switch21

Host1----- Switch12---------Switch22

There are two intents (Multipoint-to-point) in each direction
between Host1 and Host2:
Host2->Switch11>Switch12->Host1
Host1->Switch12>Switch11->Host2

2. The link between Switch11 and Switch12 is removed:

Host2 ----- Switch11---------Switch21

Host1----- Switch12---------Switch22

The two intents are suppose to be rerouted:
Host2->Switch11>Switch21>Switch22->Switch12-->Host1
Host1->Switch12>Switch22>Switch21->Switch11-->Host2

However, during the Intent recomputation/installation, only
the Intent from Host1 to Host2 is installed properly,
because in the mean time the following exception is triggered:

2015-02-13 21:42:05,481 | ERROR | onos-intent-6 | IntentManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Error submitt\
ing batches:
java.lang.NullPointerException
at java.util.ArrayList.addAll(ArrayList.java:577)[:1.8.0_25]
at org.onosproject.net.intent.impl.IntentManager.executeReplacementPhase(IntentManager.java:430)[153:org.onosproject.onos-core-net:1.0.2.SNAPSHOT]
at org.onosproject.net.intent.impl.IntentManager.processIntentUpdate(IntentManager.java:565)[153:org.onosproject.onos-core-net:1.0.2.SNAPSHOT]
at org.onosproject.net.intent.impl.IntentManager.access$800(IntentManager.java:80)[153:org.onosproject.onos-core-net:1.0.2.SNAPSHOT]
at org.onosproject.net.intent.impl.IntentManager$IntentInstallMonitor.buildIntentUpdates(IntentManager.java:786)[153:org.onosproject.onos-core-net:1\
.0.2.SNAPSHOT]
at org.onosproject.net.intent.impl.IntentManager$IntentInstallMonitor.run(IntentManager.java:919)[153:org.onosproject.onos-core-net:1.0.2.SNAPSHOT]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_25]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_25]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_25]
2015-02-13 21:42:05,482 | ERROR | onos-intent-6 | IntentManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Walk the plan\
k, matey...
2015-02-13 21:42:10,413 | INFO | d wheel timer #2 | HostLocationProvider | 129 - org.onosproject.onos-host-provider - 1.0.2.SNAPSHOT | Triggeri\
ng probe on device StoredHost{id=00:0C:29:FF:94:3B/-1, mac=00:0C:29:FF:94:3B, vlan=-1, location=HostLocation

{elementId=of:cc4e240c08000000, portNumber=675}

,\
ipAddresses=[192.168.112.1, 192.168.111.1]}
2015-02-13 21:42:10,446 | INFO | d wheel timer #2 | HostLocationProvider | 129 - org.onosproject.onos-host-provider - 1.0.2.SNAPSHOT | Triggeri\
ng probe on device StoredHost{id=00:0C:29:AF:49:6B/-1, mac=00:0C:29:AF:49:6B, vlan=-1, location=HostLocation

{elementId=of:cc4e240c0c000000, portNumber=673}

,\
ipAddresses=[192.168.121.1]}
2015-02-13 21:42:13,092 | INFO | vlindeva.event-4 | IntentManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Execute 1 ope\
ration(s).
2015-02-13 21:42:14,882 | INFO | d wheel timer #2 | LinkManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Links for con\
nection point ConnectPoint

{elementId=of:cc4e240c0c000000, portNumber=676}

vanished
2015-02-13 21:42:40,512 | INFO | d wheel timer #2 | HostLocationProvider | 129 - org.onosproject.onos-host-provider - 1.0.2.SNAPSHOT | Triggeri\
ng probe on device StoredHost{id=00:0C:29:FF:94:3B/-1, mac=00:0C:29:FF:94:3B, vlan=-1, location=HostLocation

{elementId=of:cc4e240c08000000, portNumber=675}

,\
ipAddresses=[192.168.112.1, 192.168.111.1]}
2015-02-13 21:42:40,544 | INFO | d wheel timer #2 | HostLocationProvider | 129 - org.onosproject.onos-host-provider - 1.0.2.SNAPSHOT | Triggeri\
ng probe on device StoredHost{id=00:0C:29:AF:49:6B/-1, mac=00:0C:29:AF:49:6B, vlan=-1, location=HostLocation

{elementId=of:cc4e240c0c000000, portNumber=673}

,\
ipAddresses=[192.168.121.1]}
2015-02-13 21:42:40,631 | INFO | vlindeva.event-4 | IntentManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Execute 1 ope\
ration(s).
2015-02-13 21:42:42,149 | WARN | onos-intent-9 | IntentManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Install reque\
st timed out: IntentOperations{operations=[IntentOperation{type=SUBMIT, intentId=0x1071, intent=MultiPointToSinglePointIntent{id=0x1071, appId=DefaultApplic\
ationId

{id=5, name=org.onosproject.sdnip}

, selector=DefaultTrafficSelector{criteria=[IPV4_DST

{ip=192.168.2.0/24}

, ETH_TYPE

{ethType=800}

]}, treatment=Default\
TrafficTreatment{instructions=[ETH_DST

{mac=00:0C:29:AF:49:6B}

]}, ingress=[ConnectPoint

{elementId=of:cc4e240c08000000, portNumber=675}

], egress=ConnectPoint

{\ elementId=of:cc4e240c0c000000, portNumber=673}

, constraints=[]}}]}
2015-02-13 21:42:42,662 | ERROR | onos-intent-4 | IntentManager | 153 - org.onosproject.onos-core-net - 1.0.2.SNAPSHOT | Walk the plan\
k, matey...
2015-02-13 21:43:10,613 | INFO | d wheel timer #2 | HostLocationProvider | 129 - org.onosproject.onos-host-provider - 1.0.2.SNAPSHOT | Triggeri\
ng probe on device StoredHost{id=00:0C:29:FF:94:3B/-1, mac=00:0C:29:FF:94:3B, vlan=-1, location=HostLocation

{elementId=of:cc4e240c08000000, portNumber=675}

,\
ipAddresses=[192.168.112.1, 192.168.111.1]}