Major Description
This is a bug introduced by PIG-3342 - Allow conditions in case statement.
If 1) there are an even number of when branches, and 2) there is the else branch, case statement with conditions fails with the following error:
Caused by: org.apache.pig.impl.logicalLayer.validators.TypeCheckerException: ERROR 1057: <line 2, column 14> LOGenerate expression plan can only have one output
This is because the logic of determining whether case statement has the else branch is incorrect. This doesn't happen when conditions are not used in case statement.