tree 232585d73e684129362f348ebf2f02e43a9e3784
parent ef51104f7f2181dba4bb73fb5d7ae8611fa76ee9
author Alice Fan <fan309@gmail.com> 1570560803 -0700
committer Impala Public Jenkins <impala-public-jenkins@cloudera.com> 1573170966 +0000

IMPALA-9023: Fix IllegalStateException in SimplifyConditionalsRule

For 'case' function, if left WHEN condition is true, SimplifyConditionalsRule
will cast the THEN result-expression to original expression's type before return
result. In this Jira, we would like to remove the cast function for two reasons:
1. SimplifyConditionalsRule only applys to analyzed expression, which means
expression has already been casted to compatible type before it reaches the
expression rewrite step.
2. The cast function will cause IllegalStateException when 'CASE WHEN TRUE'
appearing in the where conjunction. For example:
Query: select * from functional.alltypessmall where case when true then id < 50 END
ERROR: IllegalStateException: null

Testing:
- Added e2e test to exprs.test
- Added unit test to ExprRewriteRulesTest
- Added unit test to ExprRewriterTest

Change-Id: I640d577200e76121c72685e4aaba1ef312a2d8b4
Reviewed-on: http://gerrit.cloudera.org:8080/14540
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>