dawidwys commented on a change in pull request #12411:
URL: https://github.com/apache/flink/pull/12411#discussion_r434513273
##########
File path:
flink-table/flink-table-common/src/main/java/org/apache/flink/table/functions/BuiltInFunctionDefinitions.java
##########
@@ -919,7 +920,8 @@
new BuiltInFunctionDefinition.Builder()
.name("cast")
.kind(SCALAR)
- .outputTypeStrategy(TypeStrategies.MISSING)
+ .inputTypeStrategy(SPECIFIC_FOR_CAST)
+
.outputTypeStrategy(nullable(ConstantArgumentCount.to(0),
TypeStrategies.argument(1)))
Review comment:
After an offline discussion we said it's okay as it has very limited
scope. The array approach has the downside that it does not support natively
open ended ranges.
##########
File path:
flink-table/flink-table-common/src/main/java/org/apache/flink/table/types/inference/strategies/CastInputTypeStrategy.java
##########
@@ -0,0 +1,85 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.flink.table.types.inference.strategies;
+
+import org.apache.flink.annotation.Internal;
+import org.apache.flink.table.functions.BuiltInFunctionDefinitions;
+import org.apache.flink.table.functions.FunctionDefinition;
+import org.apache.flink.table.types.DataType;
+import org.apache.flink.table.types.inference.ArgumentCount;
+import org.apache.flink.table.types.inference.CallContext;
+import org.apache.flink.table.types.inference.ConstantArgumentCount;
+import org.apache.flink.table.types.inference.InputTypeStrategy;
+import org.apache.flink.table.types.inference.Signature;
+import org.apache.flink.table.types.logical.LegacyTypeInformationType;
+import org.apache.flink.table.types.logical.LogicalType;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+import static
org.apache.flink.table.types.logical.utils.LogicalTypeCasts.supportsExplicitCast;
+
+/**
+ * {@link InputTypeStrategy} specific for {@link
BuiltInFunctionDefinitions#CAST}.
+ *
+ * <p>It expects two arguments where the type of first one must be castable to
the type of the second
+ * one. The second one must be a type literal.
+ */
+@Internal
+public final class CastInputTypeStrategy implements InputTypeStrategy {
+
+ @Override
+ public ArgumentCount getArgumentCount() {
+ return ConstantArgumentCount.of(2);
+ }
+
+ @Override
+ public Optional<List<DataType>> inferInputTypes(CallContext
callContext, boolean throwOnFailure) {
+ // check for type literal
+ if (!callContext.isArgumentLiteral(1) ||
!callContext.getArgumentValue(1, DataType.class).isPresent()) {
+ return Optional.empty();
Review comment:
nit: throw an exception?
##########
File path:
flink-table/flink-table-common/src/test/java/org/apache/flink/table/types/inference/TypeStrategiesTest.java
##########
@@ -113,37 +113,60 @@
.inputTypes()
.expectErrorMessage("Could not infer an output
type for the given arguments. Untyped NULL received."),
- TestSpec.forStrategy(
- "Infer a row type",
- TypeStrategies.ROW)
+ TestSpec
+ .forStrategy(
+ "Infer a row type",
+ TypeStrategies.ROW)
.inputTypes(DataTypes.BIGINT(),
DataTypes.STRING())
.expectDataType(DataTypes.ROW(
DataTypes.FIELD("f0",
DataTypes.BIGINT()),
DataTypes.FIELD("f1",
DataTypes.STRING())).notNull()
),
- TestSpec.forStrategy(
- "Infer an array type",
- TypeStrategies.ARRAY)
+ TestSpec
+ .forStrategy(
+ "Infer an array type",
+ TypeStrategies.ARRAY)
.inputTypes(DataTypes.BIGINT(),
DataTypes.BIGINT())
.expectDataType(DataTypes.ARRAY(DataTypes.BIGINT()).notNull()),
- TestSpec.forStrategy(
- "Infer a map type",
- TypeStrategies.MAP)
+ TestSpec.
+ forStrategy(
+ "Infer a map type",
+ TypeStrategies.MAP)
.inputTypes(DataTypes.BIGINT(),
DataTypes.STRING().notNull())
.expectDataType(DataTypes.MAP(DataTypes.BIGINT(),
DataTypes.STRING().notNull()).notNull()),
+ TestSpec
+ .forStrategy(
+ "Cascading to nullable type",
+
nullable(explicit(DataTypes.BOOLEAN().notNull())))
+ .inputTypes(DataTypes.BIGINT().notNull(),
DataTypes.VARCHAR(2).nullable())
+ .expectDataType(DataTypes.BOOLEAN().nullable()),
+
+ TestSpec
+ .forStrategy(
+ "Cascading to not null type",
+
nullable(explicit(DataTypes.BOOLEAN().nullable())))
+ .inputTypes(DataTypes.BIGINT().notNull(),
DataTypes.VARCHAR(2).notNull())
+ .expectDataType(DataTypes.BOOLEAN().notNull()),
+
TestSpec.forStrategy(
- "Cascading to nullable type",
-
nullable(explicit(DataTypes.BOOLEAN().notNull())))
+ "Cascading to not null type but only
consider first argument",
+ nullable(ConstantArgumentCount.to(0),
explicit(DataTypes.BOOLEAN().nullable())))
+ .inputTypes(DataTypes.BIGINT().notNull(),
DataTypes.VARCHAR(2).nullable())
+ .expectDataType(DataTypes.BOOLEAN().notNull()),
+
+ TestSpec.forStrategy(
+ "Cascading to null type but only
consider first two argument",
+ nullable(ConstantArgumentCount.to(1),
explicit(DataTypes.BOOLEAN().nullable())))
.inputTypes(DataTypes.BIGINT().notNull(),
DataTypes.VARCHAR(2).nullable())
.expectDataType(DataTypes.BOOLEAN().nullable()),
TestSpec.forStrategy(
- "Cascading to not null type",
-
nullable(explicit(DataTypes.BOOLEAN().nullable())))
- .inputTypes(DataTypes.BIGINT().notNull(),
DataTypes.VARCHAR(2).notNull())
+ "Cascading to not null type but only
consider first two argument",
+
nullable(ConstantArgumentCount.between(1, 2),
explicit(DataTypes.BOOLEAN().nullable())))
Review comment:
bump
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