IIUC, since the `lateral View*` matches an empty string in optional blocks,
antlr shows such a warning;
fromClause
: FROM relation (',' relation)* (pivotClause | lateralView*)?
;
http://www.antlr.org/api/JavaTool/org/antlr/v4/tool/ErrorType.html#EPSILON_OPTIONAL
On Mon, May 14, 2018 at 9:47 PM, Sean Owen <sro...@gmail.com> wrote:
> I don't know anything about it directly, but seems like it would have been
> caused by https://github.com/apache/spark/commit/
> e3201e165e41f076ec72175af246d12c0da529cf
> The "?" in fromClause is what's generating the warning, and it may be
> ignorable.
>
> On Mon, May 14, 2018 at 12:38 AM Reynold Xin <r...@databricks.com> wrote:
>
>> Just saw this in one of my PR that's doc only:
>>
>> [error] warning(154): SqlBase.g4:400:0: rule fromClause contains an optional
>> block with at least one alternative that can match an empty string
>>
>>
>>
>>
--
---
Takeshi Yamamuro
