[HELIX-702] Fix Some Potential NPE

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: brettkk
• Created: 30/Apr/18 03:42
• Updated: 30/Apr/18 03:42

Description

We have developed a static analysis tool NPEDetector to find some potential NPE. Our analysis shows that some callees may return null in corner case(e.g. node crash , IO exception), some of their callers have  !=null check but some do not have. In this issue we post a patch which can add  !=null  based on existed !=null  check. For example:

Callee ClusterDataCache#getStateModelDef:

public StateModelDefinition getStateModelDef(String stateModelDefRef) {
  if (stateModelDefRef == null) {
    return null;
  }
  return _stateModelDefMap.get(stateModelDefRef);
}

Caller AutoRebalancer#computeNewIdealState have !=null:

StateModelDefinition stateModelDef = clusterData.getStateModelDef(stateModelName);
if (stateModelDef == null) {
  LOG.error("State Model Definition null for resource: " + resourceName);
  throw new HelixException("State Model Definition null for resource: " + resourceName);
}

but another caller DelayedAutoRebalancer#computeNewIdealState does not have !=null check:

StateModelDefinition stateModelDef =
    clusterData.getStateModelDef(currentIdealState.getStateModelDefRef());
LinkedHashMap<String, Integer> stateCountMap =
    stateModelDef.getStateCountMap(activeNodes.size(), replicaCount);

So we will add below code in non-(!=null) caller DelayedAutoRebalancer#computeNewIdealState

if (stateModelDef == null) {
    throw new HelixException("State Model Definition null for resource:" + resourceName);
}

 

But due to we are not very  familiar with HELIX, hope some expert can review it.

Thanks.