Antlr no viable alternative at input when the keyword is POINT - antlr4

Question

import org.antlr.v4.runtime.tree.ParseTree;
import org.apache.shardingsphere.sql.parser.core.parser.SQLParserExecutor;
import org.junit.Test;
import javax.xml.bind.SchemaOutputResolver;
public class T1 {
#Test
public void t1() {
ParseTree parseTree = new SQLParserExecutor("MySQL", "insert into T_NAME (POINT) values (?)").execute().getRootNode();
}
}
This code will report the following error:
line 1:20 no viable alternative at input '(POINT'
When I use other column names, it’s all right, but POINT doesn’t work. Why?
Java project, pom.xml:
<dependency>
<groupId>org.apache.shardingsphere</groupId>
<artifactId>sharding-jdbc-spring-namespace</artifactId>
<version>4.1.1</version>
</dependency>

Answer 1

I suspect that all (MySQL), or more, keywords would trigger this error (POLYGON probably also produces this error). The grammar probably is trying to match an identifier, but since the input POINTS is already matched as a keyword, it fails to match it properly.
Something like this:
insert_stat
: INSERT INTO? table_name '(' column_names ')' ...
;
column_names
: IDENTIFIER ( ',' IDENTIFIER )*
;
Looking at the Github issue, one of the maintainers indicated that the 5.0.0-alpha properly handles this, meaning they probably did something like this to fix it:
insert_stat
: INSERT INTO? table_name '(' column_names ')' ...
;
column_names
: identifier ( ',' identifier )*
;
identifier
: IDENTIFIER
| POINT
| POLYGON
| ...
;
I.e.: they extended the set of valid identifiers inside the parser.

Answer 2

Thanks for #Bart's comment Here. This bug has been fixed from 5.0.0-alpha.
BTW, ShardingSphere supports many mainstream RDBMS, like MySQL, PostgreSQL, SQLServer and Oracle. Therefore you will see a great many g4 files in this repo. Ideally, these definitions in Antlr g4 file are expected to be aligned with the corresponding official SQL docs. So if there is any mismatch, please report that at ISSUES. Thanks a lot.