[SPARK-13277][SQL] ANTLR ignores other rule using the USING keyword

[viirya]

JIRA: https://issues.apache.org/jira/browse/SPARK-13277

There is an ANTLR warning during compilation:

warning(200): org/apache/spark/sql/catalyst/parser/SparkSqlParser.g:938:7: 
Decision can match input such as "KW_USING Identifier" using multiple alternatives: 2, 3

As a result, alternative(s) 3 were disabled for that input

This patch is to fix it.

[viirya]

cc @hvanhovell

[SparkQA]

Test build #51089 has finished for PR 11168 at commit 4cb9d2a.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[hvanhovell]

@viirya thanks for working on this. Do you have an idea what functionality was disabled?

[viirya]

@hvanhovell there are two alternatives to match tableProvider rule:

     tableProvider
     tableOpts?
     (KW_AS selectStatementWithCTE)?

And

(LPAREN columnNameTypeList RPAREN)?
     (p=tableProvider?)
...

Because (LPAREN columnNameTypeList RPAREN) is optional, an input KW_USING Identifier can be matched with both paths. So the warning is emitted and path 1 is chosen and path 2 is disabled. Actually it doesn't affect the functionality we need.

[hvanhovell]

LGTM

[hvanhovell]

Merging to master. Thanks!

[rxin]

Can we add a unit test for this?

[hvanhovell]

We could add a unit test for this specific case. But I am also looking for a way to treat these warnings as compile errors; which would be a lot better.

[rxin]

Yup that's a great idea.