jchen5 opened a new pull request, #42007: URL: https://github.com/apache/spark/pull/42007
### What changes were proposed in this pull request? `null IN (empty list)` incorrectly evaluates to null, when it should evaluate to false. (The reason it should be false is because a IN (b1, b2) is defined as a = b1 OR a = b2, and an empty IN list is treated as an empty OR which is false. This is specified by ANSI SQL.) Many places in Spark execution (In, InSet, InSubquery) and optimization (OptimizeIn, NullPropagation) implemented this wrong behavior. This is a longstanding correctness issue which has existed since null support for IN expressions was first added to Spark. This PR fixes the optimization rules OptimizeIn and NullPropagation, which followed the preexisting, incorrect execution behavior. The execution fixes will be in the next PR. The behavior is under a flag, which will be available to revert to the legacy behavior if needed. This flag is set to disable the new behavior until all of the fix PRs are complete. See [this doc](https://docs.google.com/document/d/15ttcB3OjGx5_WFKHB2COjQUbFHj5LrfNQv_d26o-wmI/edit) for more information. ### Why are the changes needed? Fix wrong SQL semantics ### Does this PR introduce _any_ user-facing change? Not yet, but will fix wrong SQL semantics when enabled ### How was this patch tested? Add unit tests and sql tests. -- 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]
