raminqaf commented on code in PR #29073: URL: https://github.com/apache/flink/pull/29073#discussion_r3924823272
########## flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/AbstractVariantToConstructedCastRule.java: ########## @@ -0,0 +1,71 @@ +/* + * 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.planner.functions.casting; + +import org.apache.flink.table.types.logical.LogicalType; +import org.apache.flink.types.variant.Variant; + +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.methodCall; + +/** + * Base class for the rules that cast a {@link + * org.apache.flink.table.types.logical.LogicalTypeRoot#VARIANT} to a constructed target, imposing a + * schema on a variant. A constructed cast is the scalar cast applied to every leaf plus a shape + * check at each level, so the recursion bottoms out at the same scalar cast the primitive and + * string rules perform and no new leaf semantics are introduced. + * + * <p>A constructed cast can always fail, on a shape mismatch, an unreadable leaf, or a missing + * {@code NOT NULL} field, so {@code TRY_CAST} wraps the whole value and returns {@code NULL} for + * any failure rather than a partial result. + */ +abstract class AbstractVariantToConstructedCastRule<OUT> + extends AbstractNullAwareCodeGeneratorCastRule<Variant, OUT> { + + protected AbstractVariantToConstructedCastRule(CastRulePredicate predicate) { + super(predicate); + } + + @Override + public boolean canFail(LogicalType inputLogicalType, LogicalType targetLogicalType) { + return true; + } + + /** + * Treats a variant that stores a JSON {@code null} as a {@code NULL} input, so a top-level JSON + * null casts to SQL {@code NULL} before any shape check runs. Only applied for a nullable + * target: a {@code NOT NULL} result cannot carry {@code NULL}, so a null-valued variant then + * fails the shape check as a regular mismatch. Review Comment: Replaced all the JSON to VARIANT ########## flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/functions/casting/VariantToArrayCastRule.java: ########## @@ -0,0 +1,171 @@ +/* + * 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.planner.functions.casting; + +import org.apache.flink.table.data.ArrayData; +import org.apache.flink.table.data.GenericArrayData; +import org.apache.flink.table.planner.codegen.CodeGenUtils; +import org.apache.flink.table.runtime.functions.VariantCastUtils; +import org.apache.flink.table.types.logical.ArrayType; +import org.apache.flink.table.types.logical.LogicalType; +import org.apache.flink.table.types.logical.LogicalTypeRoot; +import org.apache.flink.types.variant.Variant; + +import static org.apache.flink.table.planner.codegen.CodeGenUtils.newName; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.constructorCall; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.methodCall; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.newArray; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.staticCall; +import static org.apache.flink.table.planner.functions.casting.CastRuleUtils.strLiteral; + +/** + * {@link LogicalTypeRoot#VARIANT} to {@link LogicalTypeRoot#ARRAY} cast rule. + * + * <p>The variant must be an array, otherwise the cast fails. Each element is itself a variant and + * casts to the target element type by the full {@code VARIANT}-to-element rule, recursively. An + * element that stores a JSON {@code null} maps to SQL {@code NULL} when the element type is + * nullable and fails the cast when it is {@code NOT NULL}. The exception is a {@code VARIANT} + * element type: there the element cast is the identity, so a JSON {@code null} element is kept as a + * variant null rather than downgraded to SQL {@code NULL}. + */ +class VariantToArrayCastRule extends AbstractVariantToConstructedCastRule<ArrayData> { + + static final VariantToArrayCastRule INSTANCE = new VariantToArrayCastRule(); + + private VariantToArrayCastRule() { + super( + CastRulePredicate.builder() + .predicate( + (input, target) -> + input.is(LogicalTypeRoot.VARIANT) + && target.is(LogicalTypeRoot.ARRAY) + && CastRuleProvider.resolve( + input, + ((ArrayType) target) + .getElementType()) + != null) + .build()); + } + + /* Example generated code for ARRAY<INT>: + + int arraySize$2 = + org.apache.flink.table.runtime.functions.VariantCastUtils.arraySize( + variant$1, "ARRAY<INT>"); + java.lang.Integer[] objArray$3 = new java.lang.Integer[arraySize$2]; + for (int i$4 = 0; i$4 < arraySize$2; i$4++) { + org.apache.flink.types.variant.Variant element$5 = variant$1.getElement(i$4); + if (!element$5.isNull()) { + result$6 = + ((int) org.apache.flink.table.runtime.functions.VariantCastUtils.toIntegral( + element$5, -2147483648L, 2147483647L, "INTEGER")); + objArray$3[i$4] = result$6; + } + } + result$0 = new org.apache.flink.table.data.GenericArrayData(objArray$3); + + A JSON null element leaves the slot null (SQL NULL); a NOT NULL element type emits a throw instead. + + */ + @Override + protected String generateCodeBlockInternal( + CodeGeneratorCastRule.Context context, + String inputTerm, + String returnVariable, + LogicalType inputLogicalType, + LogicalType targetLogicalType) { + final LogicalType elementType = ((ArrayType) targetLogicalType).getElementType(); + final String elementTypeTerm = arrayElementType(elementType); + final String sizeTerm = newName(context.getCodeGeneratorContext(), "arraySize"); + final String arrayTerm = newName(context.getCodeGeneratorContext(), "objArray"); + final String elementTerm = newName(context.getCodeGeneratorContext(), "element"); + + // For a typed element the JSON null is handled in the loop below, so the inner cast is the Review Comment: https://github.com/apache/flink/pull/29073#discussion_r3924823272 -- This is an automated message from the Apache Git Service. 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