yaooqinn opened a new pull request #29538: URL: https://github.com/apache/spark/pull/29538
### What changes were proposed in this pull request? This PR fixes the doc error and add a migration guide for datetime pattern. ### Why are the changes needed? This is a bug of the doc that we inherited from JDK https://bugs.openjdk.java.net/browse/JDK-8169482 The SimpleDateFormatter(**F Day of week in month**) we used in 2.x and the DatetimeFormatter(**F week-of-month**) we use now both have the opposite meanings to what they declared in the java docs. And unfortunately, this also leads to silent data change in Spark too. The `week-of-month` is actually the pattern `W` in DatetimeFormatter, which is banned to use in Spark 3.x. If we want to keep pattern `F`, we need to accept the behavior change with proper migration guide and fix the doc in Spark ### Does this PR introduce _any_ user-facing change? <!-- Note that it means *any* user-facing change including all aspects such as the documentation fix. If yes, please clarify the previous behavior and the change this PR proposes - provide the console output, description and/or an example to show the behavior difference if possible. If possible, please also clarify if this is a user-facing change compared to the released Spark versions or within the unreleased branches such as master. If no, write 'No'. --> Yes, doc changed ### How was this patch tested? <!-- If tests were added, say they were added here. Please make sure to add some test cases that check the changes thoroughly including negative and positive cases if possible. If it was tested in a way different from regular unit tests, please clarify how you tested step by step, ideally copy and paste-able, so that other reviewers can test and check, and descendants can verify in the future. If tests were not added, please describe why they were not added and/or why it was difficult to add. --> passing ci doc generating job ---------------------------------------------------------------- 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: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
