[CALCITE-4409] Improve exception when RelBuilder tries to create a field on a non-struct expression

• Type: Task
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 1.27.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Ruben Q L
• Reporter: Ruben Q L
• Created: 19/Nov/20 15:44
• Updated: 03/Jun/21 22:32
• Resolved: 26/Nov/20 11:24

Description

A simple test like this (to added in RelBuilderTest), where RelBuilder#field(RexNode e, String name) is called and the first parameter's type is not a struct:

  @Test void test() {
    final RelBuilder builder = RelBuilder.create(config().build());
    builder.scan("EMP")
        .project(
            builder.field(builder.field("EMPNO"), "abc"))
        .build();
  }

Fails with a NPE:

java.lang.NullPointerException
	at org.apache.calcite.rel.type.RelDataTypeImpl.getField(RelDataTypeImpl.java:82)
	at org.apache.calcite.rex.RexBuilder.makeFieldAccess(RexBuilder.java:182)
	at org.apache.calcite.tools.RelBuilder.field(RelBuilder.java:502)

This situation could be handled with a more gracefully exit (IllegalArgumentException) and a more useful exception message.

Issue Links

• links to: GitHub Pull Request #2272