[CALCITE-2687] Is distinct from could lead to Exceptions in ReduceExpressionRule

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.18.0
• Assignee: Zoltan Haindrich
• Reporter: Zoltan Haindrich
• Created: 20/Nov/18 12:29
• Updated: 27/Feb/24 22:23
• Resolved: 28/Nov/18 05:40

Description

Test:

  @Test
  public void testReduceConstants4() throws Exception {
    HepProgram program = new HepProgramBuilder()
        .addRuleInstance(ReduceExpressionsRule.PROJECT_INSTANCE)
        .addRuleInstance(ReduceExpressionsRule.FILTER_INSTANCE)
        .addRuleInstance(ReduceExpressionsRule.JOIN_INSTANCE)
        .build();

    String sql = "select e.mgr is not distinct from f.mgr from emp e join emp f on (e.mgr=f.mgr) where e.mgr is null";
    sql(sql).with(program)
        .check();
  }

Unfortunately the exception doesn't have a stacktrace by default; just some type:

org.apache.calcite.adapter.enumerable.RexToLixTranslator$AlwaysNull

Translation is not possible at this point: https://github.com/apache/calcite/blob/d32ee5c320938b5c34ce09df2276c9570c27a301/core/src/main/java/org/apache/calcite/adapter/enumerable/RexToLixTranslator.java#L746

the underlying rexNode is:

CAST(null):INTEGER NOT NULL

which is problematic

Issue Links

• is caused by: CALCITE-2675 Type validation error as ReduceExpressionRule fails to preserve type nullability
• links to: PR#929