Yes Takeshi, I agree, I think we can easily fix the warning replacing the * with +, since the two options are not required. I will test this fix and create a PR when it is ready.
Thanks, Marco 2018-05-14 15:08 GMT+02:00 Takeshi Yamamuro <linguin....@gmail.com>: > 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/e3201e165e41f076ec >> 72175af246d12c0da529cf >> 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 >