25 is not a valid choice for -java-output-version

[He-Pin]

Compiler version

Scala 3.3.7
Java 25
With Scala maven plugin 4.9.8

Minimized code

Output

[INFO] compiling 17 Scala sources and 7 Java sources to /home/admin/aone-build/tmcp/tmcp-jsonnet/target/classes ...
[ERROR] : 25 is not a valid choice for -java-output-version
[INFO] :   scalac -help  gives more information
[ERROR] one error found

Expectation

It should support 25, because https://docs.scala-lang.org/overviews/jdk-compatibility/overview.html

[WojciechMazur]

Still fails in latest nightly 3.3.8-RC1-bin-20260105-6403a50-NIGHTLY
It's strange becouse JDK 25 list listed in supported backend versions in 3.3.7

scala3/compiler/src/dotty/tools/backend/jvm/BackendUtils.scala

Lines 190 to 191 in 07335bb

	25 -> asm.Opcodes.V25
	)

It also can be found when using scala-cli compile --jvm=25 -S 3.3.7 -O -help

        -java-output-version  Compile code with classes specific to the given
                              version of the Java platform available on the
                              classpath and emit bytecode for this version.
                              Corresponds to -release flag in javac.
                              Choices : 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
                              18, 19, 20, 21, 22, 23, 24, 25

[tgodzik]

It seems I get the same issue with:
scala-cli compile --server=false -O -java-output-version:25 example.scala
but if I remove server=false it works.

val jdkVersion = JDK9Reflectors.runtimeVersionMajor(JDK9Reflectors.runtimeVersion()).intValue() looks to be pointing to the version the compiler was released with.

[tgodzik]

Looks like it was also reproducible with versions prior to 3.8.0. The JDK9Reflectors do not seem to work.

[tgodzik]

Ach, wait it was because of the default Java available on the PATH. Without server=false it was Bloop running on the newest version. My guess is that maven is not actually running JDK 25+.

[He-Pin]

This actually blocks me migrate my project to Java 25, where I have to set the source and target to be 21 now.

[tgodzik]

It works for me in a sample project, when I set java command to use JDK 25: