Hi, Martijn. Even if we upgrade scala to 2.12.15 to support Java17, it just fix the compilation of FLINK-25000 <https://issues.apache.org/jira/browse/FLINK-25000> . There is another problem[1] that Scala <=2.13 can't generate jvm11 or higher bytecode version. The flink project target class bytecode version is inconsistent between scala and java source. If we decide to upgrade scala version, how aboout scala 2.12.16, as i know from scala community, the 2.12.16 will backport 2.13 functionilies like jvm11,jvm17 target jvm class support.
[1] https://issues.apache.org/jira/browse/FLINK-27549 Martijn Visser <martijnvis...@apache.org> 于2022年5月20日周五 16:37写道： > Hi everyone, > > I would like to get some opinions from our Scala users, therefore I'm also > looping in the user mailing list. > > Flink currently is tied to Scala 2.12.7. As outlined in FLINK-12461 [1] > there is a binary incompatibility introduced by Scala 2.12.8, which > currently limits Flink from upgrading to a later Scala 2.12 version. > According to the Scala 2.12.8 release notes, "The fix is not binary > compatible: the 2.12.8 compiler omits certain methods that are generated by > earlier 2.12 compilers. However, we believe that these methods are never > used and existing compiled code will continue to work" > > We could still consider upgrading to a later Scala 2.12 version, the latest > one currently being 2.12.15. Next to any benefits that are introduced in > the newer Scala versions, it would also resolve a blocker for Flink to add > support for Java 17 [2]. > > My question to Scala users of Flink and others who have an opinion on this: > * Has any of you already manually compiled Flink with Scala 2.12.8 or > later? > * If so, have you experienced any problems with checkpoint and/or savepoint > incompatibility? > * Would you prefer Flink breaking binary compatibility by upgrading to a > later Scala 2.12 version or would you prefer Flink to stick with Scala > 2.12.7? > > Note: I know there are also questions about Scala 2.13 and Scala 3 support > in Flink; I think that deserves its own discussion thread. > > Best regards, > > Martijn Visser > https://twitter.com/MartijnVisser82 > https://github.com/MartijnVisser > > [1] https://issues.apache.org/jira/browse/FLINK-12461 > [2] https://issues.apache.org/jira/browse/FLINK-25000 > -- Best, Ran Tao
