"Unsupported class file major version 56" error in JDK 12 build

[plokhotnyuk]

[jsoniter-scala] [error] ## Exception when compiling 5 sources to /home/jenkins/workspace/scala-2.12.x-jdk12-integrate-community-build/target-0.9.16/project-builds/jsoniter-scala-f34d7e137bb3b09515c1eb076c6f60023632077e/jsoniter-scala-core/target/scala-2.12/classes
[jsoniter-scala] [error] Unsupported class file major version 56

Here is a list of projects that are immediately affected by this kind of error in the latest build:

• breeze
• curryhoward
• log4s
• jsoniter-scala
• scala-async
• scala-partest
• scalaz
• utest

[SethTisue]

thanks for the report. I'm not sure what the cause is. I plan to investigate, but I have some other, more pressing community build stuff to attend to first. I've assigned myself the issue so I don't forget.

[SethTisue]

reproducible outside of dbuild, in e.g. scala-async with just compile

the problem is also present with ++2.13.0-M5 but goes away with ++2.13.0-pre-481a78b!. that and the error message strongly suggest that fixing this requires moving to ASM 7, as was done for the 2.13.x series by scala/scala#7384

an existing ticket in this general area: scala/bug#11372

[SethTisue]

hopefully scala/scala#7780 will do the trick

[SethTisue]

it seems very likely that scala/bug#11372 is the only bug here