Funky javac crash: java.lang.AssertionError: xClassName at com.sun.tools.javac.jvm.ClassWriter.xClassName(ClassWriter.java:358)

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1

I’m exploring how hard/easy it would be to migrate a huge working Maven build of the opendaylight.org community to Gradle, and after getting over some simple initial problems (gradle init was missing dependencies from parent POM?!) am hitting a pretty cool javac crash, see below.

Anyone should be able to reproduce it easily like this:

git clone https://github.com/vorburger/infrautils.git
git checkout gradle
./gradlew build

https://bugs.openjdk.java.net/browse/JDK-8068951 makes me think this could be somehow related to a type annotation from org.eclipse.jdt:org.eclipse.jdt.annotation:2.1.0 … but it’s interesting that building under Gradle hits this, while it worked with Maven, no?

What would you do with this? It may well be more of an OpenJDK javac bug than Gradle itself, and I could reach out to OpenJDK folks, but they would likely ask for more information how to easily reproduce this without Gradle… Does Gradle do anything funky to javac? Can anyone figure out with more Gradle logging foo which Java file it’s choking on, so that we can see if a pure javac CLI would hit it as well?

> Task :parent:infrautils-testutils:compileJava FAILED
An exception has occurred in the compiler (1.8.0_161). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.AssertionError: xClassName
        at com.sun.tools.javac.jvm.ClassWriter.xClassName(ClassWriter.java:358)
        at com.sun.tools.javac.jvm.ClassWriter.writePool(ClassWriter.java:470)
        at com.sun.tools.javac.jvm.ClassWriter.writeClassFile(ClassWriter.java:1750)
        at com.sun.tools.javac.jvm.ClassWriter.writeClass(ClassWriter.java:1621)
        at com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:746)
        at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1572)
        at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1536)
        at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:901)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:860)
        at com.sun.tools.javac.main.Main.compile(Main.java:523)
        at com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:129)
        at com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:138)
        at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:50)
        at org.gradle.api.internal.tasks.compile.JdkJavaCompiler.execute(JdkJavaCompiler.java:37)
        at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.delegateAndHandleErrors(NormalizingJavaCompiler.java:98)
        at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:51)
        at org.gradle.api.internal.tasks.compile.NormalizingJavaCompiler.execute(NormalizingJavaCompiler.java:37)
        at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:35)
        at org.gradle.api.internal.tasks.compile.CleaningJavaCompilerSupport.execute(CleaningJavaCompilerSupport.java:25)
        at org.gradle.api.tasks.compile.JavaCompile.performCompilation(JavaCompile.java:156)
        at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:141)
        at org.gradle.api.tasks.compile.JavaCompile.compile(JavaCompile.java:114)
        at sun.reflect.GeneratedMethodAccessor592.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
        at org.gradle.api.internal.project.taskfactory.IncrementalTaskAction.doExecute(IncrementalTaskAction.java:50)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:124)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:113)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:95)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:73)
        at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
        at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:59)
        at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
        at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:59)
        at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:101)
        at org.gradle.api.internal.tasks.execution.FinalizeInputFilePropertiesTaskExecuter.execute(FinalizeInputFilePropertiesTaskExecuter.java:44)
        at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:91)
        at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:62)
        at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:59)
        at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
        at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
        at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:256)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:249)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:238)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:663)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:597)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
        at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
        at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
        at java.lang.Thread.run(Thread.java:748)


FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':parent:infrautils-testutils:compileJava'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0.
See https://docs.gradle.org/4.6/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 2s
47 actionable tasks: 32 executed, 15 up-to-date
2

I’ve meanwhile narrowed this down; it’s definitely beeing caused by a usage of org.eclipse.jdt:org.eclipse.jdt.annotation:2.1.0, specifically the use of its NonNull type annotation in a cast, see this commit (which removes the problematic expression, after which gradle passes) from https://github.com/vorburger/infrautils/commits/gradle-javac-cash :

private final AtomicReference<T> eventualValue = new AtomicReference<>();
....
return (@NonNull T) eventualValue.get();

A direct CLI use of javac (without Gradle or Maven) does not hit this. It therefore seems to me that must be caused be something that Gradle is doing with javac. Is there any interest from the Gradle community in me opening a bug issue on GitHub about this? If needed, I could further simplify where this was hit to have a minimal reproducer example project.

3

In the maven world this helped me overcome the stack trace and figure out where the issue really occurs, maybe there is a gradle corollary?
https://issues.apache.org/jira/browse/MCOMPILER-346