[MAPREDUCE-3344] o.a.h.mapreduce.Reducer since 0.21 blindly casts to ReduceContext.ValueIterator

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.21.0, 0.22.0, 0.23.0, 0.23.1, 2.0.0-alpha
• Fix Version/s: 0.23.1
• Labels: critical-0.22.0
• Target Version/s: 0.21.0, 0.22.0, 0.23.0, 0.23.1
• Hadoop Flags: Reviewed
• Assignee: Brock Noland
• Reporter: Brock Noland
• Created: 04/Nov/11 02:01
• Updated: 10/Mar/15 04:32
• Resolved: 07/Nov/11 20:18

Description

0.21 mapreduce.Reducer introduced a blind cast to ReduceContext.ValueIterator. There should an instanceof check around this block to ensure we don't throw a CastClassException:

       // If a back up store is used, reset it
      ((ReduceContext.ValueIterator)
          (context.getValues().iterator())).resetBackupStore();