NullPointerException when executing "select YEAR(JOINEDAT) + MONTH(JOINEDAT) from EMPS"

[Roger Shi]

Hi all,

When play with the tutorial dataset, I add one row in table EMPS. The JOINNDAT 
values is NULL in that row. By runing the SQL “select YEAR(JOINEDAT) + 
MONTH(JOINEDAT) from EMPS”, I get the following error:

java.lang.NullPointerException
                at Baz$1$1.current(Unknown Source)
                at 
org.apache.calcite.linq4j.Linq4j$EnumeratorIterator.next(Linq4j.java:672)
                at 
org.apache.calcite.avatica.util.IteratorCursor.next(IteratorCursor.java:46)
                at 
org.apache.calcite.avatica.AvaticaResultSet.next(AvaticaResultSet.java:239)
                at sqlline.IncrementalRows.hasNext(IncrementalRows.java:65)
                at sqlline.TableOutputFormat.print(TableOutputFormat.java:33)
                at sqlline.SqlLine.print(SqlLine.java:1648)
                at sqlline.Commands.execute(Commands.java:834)
                at sqlline.Commands.sql(Commands.java:733)
                at sqlline.SqlLine.dispatch(SqlLine.java:795)
                at sqlline.SqlLine.begin(SqlLine.java:668)
                at sqlline.SqlLine.start(SqlLine.java:373)
                at sqlline.SqlLine.main(SqlLine.java:265)

The generated code is:

return new org.apache.calcite.linq4j.AbstractEnumerable(){
    public org.apache.calcite.linq4j.Enumerator<Long> enumerator() {
      return new org.apache.calcite.linq4j.Enumerator<Long>(){
          public final org.apache.calcite.linq4j.Enumerator<Object[]> 
inputEnumerator = interpreter.enumerator();
          public void reset() {
            inputEnumerator.reset();
          }

          public boolean moveNext() {
            return inputEnumerator.moveNext();
          }

          public void close() {
            inputEnumerator.close();
          }

          public Object current() {
            final Integer inp9_ = (Integer) ((Object[]) 
inputEnumerator.current())[9];
            final int v = inp9_.intValue();
            return inp9_ == null ? (Long) null : 
Long.valueOf(org.apache.calcite.avatica.util.DateTimeUtils.unixDateExtract(org.apache.calcite.avatica.util.TimeUnitRange.YEAR,
 v) + 
org.apache.calcite.avatica.util.DateTimeUtils.unixDateExtract(org.apache.calcite.avatica.util.TimeUnitRange.MONTH,
 v));
          }

        };
}

  };

The highlight line should be the root cause. The main logic is generated in 
org.apache.calcite.adapter.enumerable.RexImpTable#implementNullSemantics.

It seems the highlight line escapes the null value check. What’s the right 
design here? I’d like to have a try to fix it.

Thanks,
Roger