Jim Ferenczi a4e08acdd1 Fix exists query on unmapped field in query_string (#58804)
Since #55785, exists queries rewrite to MatchNoneQueryBuilder when the field is unmapped.
This change also introduced a bug in the `query_string` query, using an unmapped field
like `_exists_:foo` throws an exception if the field is unmapped. This commit avoids the
exception if the query is built outside of an `ExistsQueryBuilder`.

Closes #58737
2020-07-02 21:52:03 +02:00
..
2020-06-17 07:35:08 -04:00