[FLINK-12461] Document binary compatibility situation with Scala beyond 2.12.8

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Workaround
• Affects Version/s: 1.8.0
• Fix Version/s: 1.12.2, 1.13.0
• Component/s: API / Scala
• Labels: pull-request-available
• Assignee: Aljoscha Krettek
• Reporter: Gaël Renoux
• Created: 09/May/19 07:51
• Updated: 20/May/22 09:28
• Resolved: 28/Jan/21 13:18

Description

When using 1.8 with Scala 2.12.8 and trying to parse a scala.Map (not a java.util.Map), I get a: java.lang.ClassNotFoundException: scala.math.Ordering$$anon$9

To reproduce:

• start with the Scala Maven archetype (org.apache.flink:flink-quickstart-scala:1.8.0)
• in the POM, set the scala.version to 2.12.8 and the scala.binary.version to 2.12
• in StreamingJob, add: env.fromElements[Map[String, Int]]()

It works with Scala 2.12.7 (well, without putting anything in the job, it fails with "No operators defined in streaming topology", which is expected).

I suspect this is linked to the binary incompatiblity of 2.12.8 with 2.12.7 (see the release note of 2.12.8), so compiling Flink with 2.12.8 instead of 2.12.7 might be enough (although it might stop working with 2.12.7?)

Issue Links

• causes: FLINK-20969 Update Scala 2.12 version to 2.12.15
• links to: GitHub Pull Request #14639
• links to: GitHub Pull Request #14780