[CALCITE-4603] Least restrictive type considers only the last element in collections of collections

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.26.0
• Fix Version/s: 1.27.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Sergey Nuyanzin
• Created: 11/May/21 15:40
• Updated: 07/Nov/23 02:34
• Resolved: 17/May/21 18:42

Description

It seems least restrictive always returns the type of the last element from the collection.
For instance for

 select array[array['hello'], array['world'], array['!']] as "array"

least restrictive gives CHAR(1) ARRAY ARRAY instead of CHAR(5) ARRAY ARRAY
for

select map[map[1.1, 2.1], map[1.1, 2.1], map[1, 1], map[1, 1]] as "map";

least restrictive gives ((INTEGER, INTEGER) MAP, (INTEGER, INTEGER) MAP) MAP instead of ((DECIMAL(2, 1), DECIMAL(2, 1)) MAP, (DECIMAL(2, 1), DECIMAL(2, 1)) MAP) MAP
for

select multiset[array['hello'], array['world'], array['!']] as "multiset";

least restrictive gives CHAR(1) ARRAY MULTISET instead of CHAR(5) ARRAY MULTISET

+ a test to reproduce

 @Test
  void testCALCITE4603() {
    SqlTypeFixture f = new SqlTypeFixture();
    SqlTypeFactoryImpl typeFactory = new SqlTypeFactoryImpl(RelDataTypeSystem.DEFAULT);
    int maxPrecision = 10;
    int minPrecision = 1;
    RelDataType leastRestrictive =
        f.typeFactory.leastRestrictive(
            Lists.newArrayList(typeFactory.createTypeWithNullability(
                typeFactory.createArrayType(typeFactory.createTypeWithNullability(
                    typeFactory.createSqlType(SqlTypeName.CHAR, maxPrecision), false), -1), false),
                typeFactory.createTypeWithNullability(
                    typeFactory.createArrayType(typeFactory.createTypeWithNullability(
                        typeFactory.createSqlType(SqlTypeName.CHAR, minPrecision), false), -1), false)));
    assertThat(leastRestrictive.getSqlTypeName(), is(SqlTypeName.ARRAY));
    assertThat(leastRestrictive.getComponentType().getPrecision(), is(maxPrecision));
  }

Issue Links

• is related to: CALCITE-6091 Char that in array or map is truncated if CASE WHEN statement contains null
• links to: GitHub Pull Request #2413