[FLINK-33200] ItemAt Expression validation fail in Table API due to type mismatch

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 1.18.0, 1.17.1
• Component/s: Table SQL / API
• Assignee: Unassigned
• Reporter: Zhenqiu Huang
• Created: 06/Oct/23 23:46
• Updated: 12/Oct/23 09:22

Description

The table schema is defined as below:

public static final DataType DATA_TYPE = DataTypes.ROW(
DataTypes.FIELD("id", DataTypes.STRING()),
DataTypes.FIELD("events", DataTypes.ARRAY(DataTypes.MAP(DataTypes.STRING(), DataTypes.STRING())))
);

public static final Schema SCHEMA = Schema.newBuilder().fromRowDataType(DATA_TYPE).build();

inTable.select(Expressions.$("events").at(1).at("eventType").as("firstEventType")

The validation fail as "eventType" is inferred as BasicTypeInfo.STRING_TYPE_INFO, the table key internally is a StringDataTypeInfo. The validation fail at

case mti: MapTypeInfo[_, _] =>
if (key.resultType == mti.getKeyTypeInfo)

{ ValidationSuccess }

else {
ValidationFailure(
s"Map entry access needs a valid key of type " +
s"'${mti.getKeyTypeInfo}', found '${key.resultType}'.")
}