cloud-fan commented on code in PR #54126: URL: https://github.com/apache/spark/pull/54126#discussion_r3345608953
########## sql/catalyst/src/main/java/org/apache/spark/sql/connector/catalog/GenerationExpression.java: ########## @@ -0,0 +1,56 @@ +/* + * 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.spark.sql.connector.catalog; + +import org.apache.spark.annotation.Evolving; +import org.apache.spark.sql.connector.expressions.Expression; + +/** + * A class that represents generated column expressions. + * <p> + * Connectors can define generated columns using either a SQL string (Spark SQL dialect) or a more + * portable connector {@link Expression expression}, whose semantics follow the ANSI SQL standard. + * <p> + * If both the SQL string and the expression are provided, Spark first attempts to convert the Review Comment: This contract is copied from `DefaultValue`, but Spark doesn't implement it for generation expressions. `DefaultValue` consumes the connector `Expression` on read in `extractCurrentDefault` (`CatalogV2Util.scala:691`, via `V2ExpressionUtils.toCatalyst`), but the generation read path `v2ColumnToStructField` (`CatalogV2Util.scala:647-657`) never reads `columnGenerationExpression()` at all — a connector-supplied V2 `Expression` is silently ignored on read. Either qualify this to say the `Expression` is currently produced on the write path only (read uses the SQL form), or implement read-path consumption to match `DefaultValue`. Non-blocking. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
