aokolnychyi commented on a change in pull request #1986: URL: https://github.com/apache/iceberg/pull/1986#discussion_r551862968
########## File path: spark3-extensions/src/main/scala/org/apache/spark/sql/catalyst/analysis/AssignmentAlignmentSupport.scala ########## @@ -0,0 +1,199 @@ +/* + * 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.catalyst.analysis + +import org.apache.spark.sql.AnalysisException +import org.apache.spark.sql.catalyst.expressions.{Alias, AnsiCast, AttributeReference, Cast, CreateNamedStruct, Expression, ExtractValue, GetStructField, Literal, NamedExpression} +import org.apache.spark.sql.catalyst.plans.logical.{Assignment, LogicalPlan} +import org.apache.spark.sql.internal.SQLConf.StoreAssignmentPolicy +import org.apache.spark.sql.types.{DataType, StructField, StructType} +import scala.collection.mutable + +trait AssignmentAlignmentSupport extends CastSupport { + + private case class ColumnUpdate(ref: Seq[String], expr: Expression) + + /** + * Aligns assignments to match table columns. + * <p> + * This method processes and reorders given assignments so that each target column gets + * an expression it should be set to. If a column does not have a matching assignment, + * it will be set to its current value. For example, if one passes a table with columns c1, c2 + * and an assignment c2 = 1, this method will return c1 = c1, c2 = 1. + * <p> + * This method also handles updates to nested columns. If there is an assignment to a particular + * nested field, this method will construct a new struct with one field updated + * preserving other fields that have not been modified. For example, if one passes a table with + * columns c1, c2 where c2 is a struct with fields n1 and n2 and an assignment c2.n2 = 1, + * this method will return c1 = c1, c2 = struct(c2.n1, 1). + * + * @param table a target table + * @param assignments assignments to align + * @return aligned assignments that match table columns + */ + protected def alignAssignments( + table: LogicalPlan, + assignments: Seq[Assignment]): Seq[Assignment] = { + + val columnUpdates = assignments.map(a => ColumnUpdate(a.key, a.value)) + val outputExprs = applyUpdates(table.output, columnUpdates) + outputExprs.zip(table.output).map { + case (expr, attr) => Assignment(attr, expr) + } + } + + private def applyUpdates( + cols: Seq[NamedExpression], + updates: Seq[ColumnUpdate], + resolver: Resolver = conf.resolver, + namePrefix: Seq[String] = Nil): Seq[Expression] = { + + // iterate through columns at the current level and find which column updates match + cols.map { col => + // find matches for this column or any of its children + val prefixMatchedUpdates = updates.filter(a => resolver(a.ref.head, col.name)) + prefixMatchedUpdates match { + // if there is no exact match and no match for children, return the column as is + case updates if updates.isEmpty => + col + + // if there is an exact match, return the assigned expression + case Seq(update) if isExactMatch(update, col, resolver) => + castIfNeeded(col, update.expr, resolver) + + // if there are matches only for children + case updates if !hasExactMatch(updates, col, resolver) => + col.dataType match { + case StructType(fields) => + applyStructUpdates(col, prefixMatchedUpdates, fields, resolver, namePrefix) + case otherType => + val colName = (namePrefix :+ col.name).mkString(".") + throw new AnalysisException( + "Updating nested fields is only supported for StructType " + + s"but $colName is of type $otherType" + ) + } + + // if there are conflicting updates, throw an exception + // there are two illegal scenarios: + // - multiple updates to the same column + // - updates to a top-level struct and its nested fields (e.g., a.b and a.b.c) + case updates if hasExactMatch(updates, col, resolver) => + val conflictingCols = updates.map(u => (namePrefix ++ u.ref).mkString(".")) + throw new AnalysisException( + "Updates are in conflict for these columns: " + + conflictingCols.distinct.mkString("[", ", ", "]")) Review comment: Done. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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