srowen commented on a change in pull request #26654: [SPARK-30009][CORE][SQL] Support different floating-point Ordering for Scala 2.12 / 2.13 URL: https://github.com/apache/spark/pull/26654#discussion_r351515871
########## File path: core/src/main/scala-2.13/org/apache/spark/util/OrderingUtil.scala ########## @@ -0,0 +1,34 @@ +/* + * 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.util + +/** + * This class only exists to bridge the difference between Scala 2.12 and Scala 2.13's + * support for floating-point ordering. It is implemented separately for both as there + * is no method that exists in both for comparison. + * + * It functions like Ordering.Double.TotalOrdering in Scala 2.13, which matches java.lang.Double + * rather than Scala 2.12's Ordering.Double in handling of NaN. Review comment: It does, for `compare`. The superclass `Ordering` then defines operations like `lt`, `lteq`, etc in terms of `compare`. But 2.12 `Ordering.Double` overrides them to use operations like `<`, `<=`. As far as I can tell it presents a consistent total ordering via `compare` already (as it appears `java.lang.Double.compare` does), but its comparisons aren't consistent with how NaNs behave in `lt`, etc. Then again... perhaps neither is Java. Its `Comparators.natural()` would work consistently, but the comparisons don't match the Java operators. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
