[CALCITE-5879] AssertionError during constant reduction of SPLIT expression that returns NULL

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.35.0
• Fix Version/s: 1.36.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Mihai Budiu
• Created: 28/Jul/23 04:44
• Updated: 10/Nov/23 11:34
• Resolved: 03/Aug/23 07:31

Description

The following test, when inserted in RelOptRulesTest, crashes at compilation time with an AssertionFailure:

@Test public void testSplit() {
    final String query = "select split('1|2|3', NULL)";
    sql(query)
        .withFactory(
            t -> t.withOperatorTable(opTab ->
                SqlLibraryOperatorTableFactory.INSTANCE.getOperatorTable(
                    SqlLibrary.BIG_QUERY))) // needed for SPLIT function
        .withRule(CoreRules.PROJECT_REDUCE_EXPRESSIONS)
        .check();
}

The error message and stack trace look like this:

java.lang.AssertionError: Cannot add expression of different type to set:
set type is RecordType(CHAR(5) NOT NULL ARRAY NOT NULL EXPR$0) NOT NULL
expression type is RecordType(CHAR(5) NOT NULL ARRAY EXPR$0) NOT NULL
set is rel#4:LogicalProject.(input=HepRelVertex#3,exprs=[SPLIT('1|2|3', null:NULL)])
expression is LogicalProject(EXPR$0=[null:CHAR(5) NOT NULL ARRAY])
  LogicalValues(tuples=[[{ 0 }]])
Type mismatch:
rowtype of original rel: RecordType(CHAR(5) NOT NULL ARRAY NOT NULL EXPR$0) NOT NULL
rowtype of new rel: RecordType(CHAR(5) NOT NULL ARRAY EXPR$0) NOT NULL
Difference:
EXPR$0: CHAR(5) NOT NULL ARRAY NOT NULL -> CHAR(5) NOT NULL ARRAY

	at org.apache.calcite.plan.RelOptUtil.verifyTypeEquivalence(RelOptUtil.java:394)
	at org.apache.calcite.plan.hep.HepRuleCall.transformTo(HepRuleCall.java:60)

Issue Links

• is related to: CALCITE-5580 Add SPLIT function (enabled in BigQuery library)
• links to: GitHub Pull Request #3344