[HELIX-563] Throw more meaningful exceptions when AutoRebalanceStrategy#computePartitionAssignment inputs are invalid

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.6.4
• Fix Version/s: 0.6.5
• Assignee: Zhen Zhang
• Reporter: Zhen Zhang
• Created: 21/Jan/15 20:23
• Updated: 17/Mar/15 21:50
• Resolved: 17/Mar/15 21:50

Description

We hit the following NPE when the input for AutoRebalanceStrategy#computePartitionAssignment is invalid:

java.lang.NullPointerException
        at org.apache.helix.controller.strategy.AutoRebalanceStrategy$Node.access$300(AutoRebalanceStrategy.java:571)
        at org.apache.helix.controller.strategy.AutoRebalanceStrategy.computeExistingNonPreferredPlacement(AutoRebalanceStrategy.java:437)
        at org.apache.helix.controller.strategy.AutoRebalanceStrategy.computePartitionAssignment(AutoRebalanceStrategy.java:122)
...

The particular problem is curMapping.keySet() is not a subset of allPartitions in the following code snippet:

AutoRebalanceStrategy strategy = new AutoRebalanceStrategy(.., allPartitions,...)
strategy.computePartitionAssignment(..., curMapping, ...)