rules_scala support for JDK 21

[gergelyfabian]

When running rules_scala (trying to compile some Scala code) with JDK 21, I receive the following exception:

Exception in thread "main" java.lang.UnsupportedOperationException: The Security Manager is deprecated and will be removed in a future release
	at java.base/java.lang.System.setSecurityManager(System.java:429)
	at io.bazel.rulesscala.worker.Worker.persistentWorkerMain(Worker.java:47)
	at io.bazel.rulesscala.worker.Worker.workerMain(Worker.java:39)
	at io.bazel.rulesscala.scalac.ScalacWorker.main(ScalacWorker.java:36)

Reproduced on Linux with:

# WORKSPACE:
# Idea from: https://gist.github.com/ghostbear/b0aa3bf1a323b38be98bb1a66db65b41
# Link can be found at: https://www.azul.com/downloads/?package=jdk#zulu
remote_java_repository(
    name = "java_21_repository",
    prefix = "zulujdk",
    sha256 = "bf4842dd3a17cfe85523be5848b5ec3bc3d811afc74feab791befa4c895c4449",
    strip_prefix = "zulu21.30.15-ca-jdk21.0.1-linux_x64",
    target_compatible_with = ["@platforms//os:linux"],
    urls = ["https://cdn.azul.com/zulu/bin/zulu21.30.15-ca-jdk21.0.1-linux_x64.tar.gz"],
    version = "21",
)

register_toolchains("//tools/jdk:java21_toolchain_definition")

# //tools/jdk:BUILD

default_java_toolchain(
    name = "java21_toolchain",
    configuration = DEFAULT_TOOLCHAIN_CONFIGURATION,
    java_runtime = "@java_21_repository//:jdk",
    javacopts = DEFAULT_JAVACOPTS,
    # jvm_opts needs to stay this one also for Java 11, it seems to be common for Java 9+ versions.
    # It includes e.g. Java module system options.
    jvm_opts = BASE_JDK9_JVM_OPTS,
    source_version = "21",
    target_version = "21",
    visibility = ["//visibility:public"],
)

[gergelyfabian]

Seems this exception is starting with JDK 18 (before it was only a warning):

https://bz.apache.org/bugzilla/show_bug.cgi?id=65381

[gergelyfabian]

Trying to localize this, it seems to occur when trying to compile any Scala code (tried scala_macro_library).

[gergelyfabian]

Reproduction: https://github.com/gergelyfabian/bazel-scala-example/tree/java_21

bazel build //...

The following changes are necessary in .bazelrc, to ensure this is reproducible:

build --java_language_version=21
build --java_runtime_version=21
build --tool_java_language_version=21
build --tool_java_runtime_version=21

[gergelyfabian]

Even when running on Java 17, when first using rules_scala (and it gets built), there is a warning:

INFO: From Building external/io_bazel_rules_scala/src/java/io/bazel/rulesscala/worker/libworker.jar (1 source file) [for tool]:
external/io_bazel_rules_scala/src/java/io/bazel/rulesscala/worker/Worker.java:48: warning: [removal] SecurityManager in java.lang has been deprecated and marked for removal
        new SecurityManager() {
            ^
external/io_bazel_rules_scala/src/java/io/bazel/rulesscala/worker/Worker.java:47: warning: [removal] setSecurityManager(SecurityManager) in System has been deprecated and marked for removal
    System.setSecurityManager(
          ^

[gergelyfabian]

Related to #1425.

[gergelyfabian]

The workaround from #1425 works. just need to add -Djava.security.manager=allow to the scala_toolchain:

scala_toolchain(
    name = "my_toolchain_impl",
    # ...
    scalac_jvm_flags = [
        "-Djava.security.manager=allow",
    ],
    # ...
)

[gergelyfabian]

The workaround fixes bazel build //... in my example project, but bazel coverage //... still fails with the same error:

	at java.base/java.lang.System.setSecurityManager(System.java:429)
	at io.bazel.rulesscala.worker.Worker.persistentWorkerMain(Worker.java:47)
	at io.bazel.rulesscala.worker.Worker.workerMain(Worker.java:39)
	at io.bazel.rulesscala.coverage.instrumenter.JacocoInstrumenter.main(JacocoInstrumenter.java:27)

[gergelyfabian]

If scalafmt is enabled, it will also fail:

Exception in thread "main" java.lang.UnsupportedOperationException: The Security Manager is deprecated and will be removed in a future release
	at java.base/java.lang.System.setSecurityManager(System.java:429)
	at io.bazel.rulesscala.worker.Worker.persistentWorkerMain(Worker.java:47)
	at io.bazel.rulesscala.worker.Worker.workerMain(Worker.java:39)
	at io.bazel.rules_scala.scalafmt.ScalafmtWorker$.main(ScalafmtWorker.scala:14)
	at io.bazel.rules_scala.scalafmt.ScalafmtWorker.main(ScalafmtWorker.scala)

[gergelyfabian]

Note: JDK 21 does not work with Scala 2.12.17, after upgrading to Scala 2.12.18 it works (with the above limitations):

https://github.com/scala/scala/releases/tag/v2.12.18

[gergelyfabian]

I could fix scalafmt by changing phase_scalafmt (is there anything exposed so that I wouldn't have to do that?):

            ctx.actions.run(
                arguments = ["--jvm_flag=-Dfile.encoding=UTF-8", "--jvm_flag=-Djava.security.manager=allow", _format_args(ctx, src, file)],
                executable = ctx.executable._fmt,
                outputs = [file],
                inputs = [ctx.file.config, src],
                execution_requirements = {"supports-workers": "1"},
                mnemonic = "ScalaFmt",
            )

[gergelyfabian]

For coverage, changed phase_coverage to:

        ctx.actions.run(
            mnemonic = "JacocoInstrumenter",
            inputs = [input_jar],
            outputs = [output_jar],
            executable = ctx.attr._code_coverage_instrumentation_worker.files_to_run,
            execution_requirements = {"supports-workers": "1"},
            arguments = ["--jvm_flag=-Djava.security.manager=allow", args],
        )

[gergelyfabian]

Uploaded my temporary fixes here: https://github.com/bazelbuild/rules_scala/compare/master...gergelyfabian:rules_scala:jdk_21?expand=1

[gergelyfabian]

One more thing that will need to get fixed I guess, when running coverage:

java.io.IOException: Error while analyzing com/.../.../DummyClazz.class.uninstrumented.
	at org.jacoco.core.analysis.Analyzer.analyzerError(Analyzer.java:163)
	at org.jacoco.core.analysis.Analyzer.analyzeClass(Analyzer.java:134)
	at com.google.testing.coverage.JacocoCoverageRunner.analyzeStructure(JacocoCoverageRunner.java:187)
	at com.google.testing.coverage.JacocoCoverageRunner.create(JacocoCoverageRunner.java:129)
	at com.google.testing.coverage.JacocoCoverageRunner$2.run(JacocoCoverageRunner.java:568)
Caused by: java.lang.IllegalArgumentException: Unsupported class file major version 65
	at com.google.testing.coverage.jarjar.org.objectweb.asm.ClassReader.<init>(ClassReader.java:199)
	at com.google.testing.coverage.jarjar.org.objectweb.asm.ClassReader.<init>(ClassReader.java:180)
	at com.google.testing.coverage.jarjar.org.objectweb.asm.ClassReader.<init>(ClassReader.java:166)
	at org.jacoco.core.internal.instr.InstrSupport.classReaderFor(InstrSupport.java:280)
	at org.jacoco.core.analysis.Analyzer.analyzeClass(Analyzer.java:107)
	at org.jacoco.core.analysis.Analyzer.analyzeClass(Analyzer.java:132)

[gergelyfabian]

Found the following related issue: bazelbuild/rules_java#141

It seems may need to retry this after upgrading to Bazel 7.