[CALCITE-5948] Use explicit casting if element type in ARRAY/MAP does not equal derived component type

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.35.0
• Fix Version/s: 1.36.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Ran Tao
• Reporter: Ran Tao
• Created: 21/Aug/23 15:21
• Updated: 16/Nov/23 16:08
• Resolved: 09/Oct/23 15:30

Description

First, we need to reach a consensus to allow types of the same family to coexist in multiset such as array and map.

It means the form like `array(1, cast(2 as tinyint))` is correct(the LeastRestrictiveType is Integer). However, this function validate success in calcite but it failed in runtime, exception stack is:

java.lang.ClassCastException: class java.lang.Byte cannot be cast to class java.lang.Integer
    at org.apache.calcite.avatica.util.AbstractCursor$IntAccessor.getInt(AbstractCursor.java:522)
    at org.apache.calcite.avatica.util.AbstractCursor$ArrayAccessor.convertValue(AbstractCursor.java:1396)
    at org.apache.calcite.avatica.util.AbstractCursor$ArrayAccessor.getObject(AbstractCursor.java:1377)
    at org.apache.calcite.avatica.util.AbstractCursor$ArrayAccessor.getArray(AbstractCursor.java:1432)
    at org.apache.calcite.avatica.util.AbstractCursor$ArrayAccessor.getString(AbstractCursor.java:1444)
    at org.apache.calcite.avatica.AvaticaResultSet.getString(AvaticaResultSet.java:241)
    at org.apache.calcite.util.JdbcTypeImpl$10.get(JdbcTypeImpl.java:112)
    at org.apache.calcite.util.JdbcTypeImpl$10.get(JdbcTypeImpl.java:109)
    at org.apache.calcite.sql.test.ResultCheckers.compareResultSetWithMatcher(ResultCheckers.java:248)
    at org.apache.calcite.sql.test.ResultCheckers$MatcherResultChecker.checkResult(ResultCheckers 

 

And `map[1, 1, 2, cast(1 as tinyint)]` is correct but calcite throw exception:

java.lang.AssertionError: Expected query to throw exception, but it did not; query [values (map[1, 1, 2, cast(1 as tinyint)])]; expected [Parameters must be of the same type]
	at org.apache.calcite.sql.test.SqlTests.checkEx(SqlTests.java:240)	at org.apache.calcite.sql.test.AbstractSqlTester.assertExceptionIsThrown(AbstractSqlTester.java:111)	at org.apache.calcite.test.SqlOperatorFixtureImpl.checkQueryFails(SqlOperatorFixtureImpl.java:174) 

 

std ArrayConstructor.

public class SqlArrayValueConstructor extends SqlMultisetValueConstructor {
  public SqlArrayValueConstructor() {
    super("ARRAY", SqlKind.ARRAY_VALUE_CONSTRUCTOR);
  }

  @Override public RelDataType inferReturnType(SqlOperatorBinding opBinding) {
    RelDataType type =
        getComponentType(
            opBinding.getTypeFactory(),
            opBinding.collectOperandTypes());
    --> we need explicit cast here
    requireNonNull(type, "inferred array element type");
    return SqlTypeUtil.createArrayType(
        opBinding.getTypeFactory(), type, false);
  }
} 

std map constructor:

public class SqlMapValueConstructor extends SqlMultisetValueConstructor {
  public SqlMapValueConstructor() {
    super("MAP", SqlKind.MAP_VALUE_CONSTRUCTOR);
  }

  @Override public RelDataType inferReturnType(SqlOperatorBinding opBinding) {
    Pair<@Nullable RelDataType, @Nullable RelDataType> type =
        getComponentTypes(
            opBinding.getTypeFactory(), opBinding.collectOperandTypes());
     --> we need explicit cast here   
     return SqlTypeUtil.createMapType(
        opBinding.getTypeFactory(),
        requireNonNull(type.left, "inferred key type"),
        requireNonNull(type.right, "inferred value type"),
        false);
  }
}

Issue Links

• contains: CALCITE-4850 Wrong result retrieving from ARRAY with mixed INTEGER and DECIMAL elements
• is blocked by: CALCITE-5960 CAST failed if SqlTypeFamily of targetType is NULL
• relates to: CALCITE-5976 Function ARRAY_PREPEND/ARRAY_APPEND/ARRAY_INSERT gives exception when inserted element type not equals array component type
• links to: GitHub Pull Request #3395