My plugin gets an incompatible dependency version at runtime

Help/Discuss
1

I am the author of editorconfig-gradle-plugin and I am new to gradle. When I add the plugin to to this sample android project https://github.com/ppalaga/android-CardView/tree/180908-antlr-clash the plugin execution fails. Here is the full log:

$ ./gradlew editorconfigCheck --no-daemon --stacktrace
> Configure project :Application 
Configuration 'compile' in project ':Application' is deprecated. Use 'implementation' instead.
The CompileOptions.bootClasspath property has been deprecated and is scheduled to be removed in Gradle 5.0. Please use the CompileOptions.bootstrapClasspath property instead.
        at org.gradle.api.tasks.compile.CompileOptions.setBootClasspath(CompileOptions.java:273)
        at org.gradle.api.tasks.compile.CompileOptions_Decorated.setBootClasspath(Unknown Source)
        at com.android.build.gradle.tasks.factory.JavaCompileConfigAction.execute(JavaCompileConfigAction.java:77)
        at com.android.build.gradle.tasks.factory.JavaCompileConfigAction.execute(JavaCompileConfigAction.java:31)
        at org.gradle.api.internal.tasks.DefaultTaskContainer.create(DefaultTaskContainer.java:148)
        at com.android.build.gradle.internal.TaskContainerAdaptor.create(TaskContainerAdaptor.java:58)
        at com.android.build.gradle.internal.scope.AndroidTaskRegistry.create(AndroidTaskRegistry.java:45)
        at com.android.build.gradle.internal.scope.AndroidTaskRegistry.create(AndroidTaskRegistry.java:87)
        at com.android.build.gradle.internal.TaskManager.createJavacTask(TaskManager.java:1510)
        at com.android.build.gradle.internal.ApplicationTaskManager.addCompileTask(ApplicationTaskManager.java:263)
        at com.android.build.gradle.internal.ApplicationTaskManager.lambda$createTasksForVariantScope$12(ApplicationTaskManager.java:224)
        at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:81)
        at com.android.build.gradle.internal.ApplicationTaskManager.createTasksForVariantScope(ApplicationTaskManager.java:220)
        at com.android.build.gradle.internal.VariantManager.createTasksForVariantData(VariantManager.java:545)
        at com.android.build.gradle.internal.VariantManager.lambda$createAndroidTasks$1(VariantManager.java:355)
        at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:81)
        at com.android.build.gradle.internal.VariantManager.createAndroidTasks(VariantManager.java:351)
        at com.android.build.gradle.BasePlugin.lambda$createAndroidTasks$5(BasePlugin.java:641)
        at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:81)
        at com.android.build.gradle.BasePlugin.createAndroidTasks(BasePlugin.java:636)
        at com.android.build.gradle.BasePlugin.lambda$null$3(BasePlugin.java:555)
        at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:81)
        at com.android.build.gradle.BasePlugin.lambda$createTasks$4(BasePlugin.java:551)
        at org.gradle.internal.event.BroadcastDispatch$ActionInvocationHandler.dispatch(BroadcastDispatch.java:91)
        at org.gradle.internal.event.BroadcastDispatch$ActionInvocationHandler.dispatch(BroadcastDispatch.java:80)
        at org.gradle.internal.event.AbstractBroadcastDispatch.dispatch(AbstractBroadcastDispatch.java:42)
        at org.gradle.internal.event.BroadcastDispatch$SingletonDispatch.dispatch(BroadcastDispatch.java:230)
        at org.gradle.internal.event.BroadcastDispatch$SingletonDispatch.dispatch(BroadcastDispatch.java:149)
        at org.gradle.internal.event.AbstractBroadcastDispatch.dispatch(AbstractBroadcastDispatch.java:58)
        at org.gradle.internal.event.BroadcastDispatch$CompositeDispatch.dispatch(BroadcastDispatch.java:324)
        at org.gradle.internal.event.BroadcastDispatch$CompositeDispatch.dispatch(BroadcastDispatch.java:234)
        at org.gradle.internal.event.ListenerBroadcast.dispatch(ListenerBroadcast.java:140)
        at org.gradle.internal.event.ListenerBroadcast.dispatch(ListenerBroadcast.java:37)
        at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
        at com.sun.proxy.$Proxy23.afterEvaluate(Unknown Source)
        at org.gradle.configuration.project.LifecycleProjectEvaluator.notifyAfterEvaluate(LifecycleProjectEvaluator.java:76)
        at org.gradle.configuration.project.LifecycleProjectEvaluator.doConfigure(LifecycleProjectEvaluator.java:70)
        at org.gradle.configuration.project.LifecycleProjectEvaluator.access$100(LifecycleProjectEvaluator.java:34)
        at org.gradle.configuration.project.LifecycleProjectEvaluator$ConfigureProject.run(LifecycleProjectEvaluator.java:110)
        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.configuration.project.LifecycleProjectEvaluator.evaluate(LifecycleProjectEvaluator.java:50)
        at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:666)
        at org.gradle.api.internal.project.DefaultProject.evaluate(DefaultProject.java:135)
        at org.gradle.execution.TaskPathProjectEvaluator.configure(TaskPathProjectEvaluator.java:35)
        at org.gradle.execution.TaskPathProjectEvaluator.configureHierarchy(TaskPathProjectEvaluator.java:62)
        at org.gradle.configuration.DefaultBuildConfigurer.configure(DefaultBuildConfigurer.java:38)
        at org.gradle.initialization.DefaultGradleLauncher$ConfigureBuild.run(DefaultGradleLauncher.java:249)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$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.initialization.DefaultGradleLauncher.configureBuild(DefaultGradleLauncher.java:167)
        at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:126)
        at org.gradle.initialization.DefaultGradleLauncher.executeTasks(DefaultGradleLauncher.java:109)
        at org.gradle.internal.invocation.GradleBuildController$1.call(GradleBuildController.java:78)
        at org.gradle.internal.invocation.GradleBuildController$1.call(GradleBuildController.java:75)
        at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:152)
        at org.gradle.internal.invocation.GradleBuildController.doBuild(GradleBuildController.java:100)
        at org.gradle.internal.invocation.GradleBuildController.run(GradleBuildController.java:75)
        at org.gradle.tooling.internal.provider.ExecuteBuildActionRunner.run(ExecuteBuildActionRunner.java:28)
        at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
        at org.gradle.tooling.internal.provider.ValidatingBuildActionRunner.run(ValidatingBuildActionRunner.java:32)
        at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner$1.run(RunAsBuildOperationBuildActionRunner.java:43)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$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.launcher.exec.RunAsBuildOperationBuildActionRunner.run(RunAsBuildOperationBuildActionRunner.java:40)
        at org.gradle.tooling.internal.provider.SubscribableBuildActionRunner.run(SubscribableBuildActionRunner.java:51)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:47)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:30)
        at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:39)
        at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:25)
        at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:80)
        at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:53)
        at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:57)
        at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:32)
        at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:36)
        at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:25)
        at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:43)
        at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:29)
        at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:69)
        at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:30)
        at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:59)
        at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:44)
        at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:45)
        at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:30)
        at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:51)
        at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:173)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:291)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:264)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:33)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:257)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:191)
        at org.gradle.launcher.Main.doAction(Main.java:33)
        at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:60)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:37)
        at org.gradle.launcher.GradleMain.main(GradleMain.java:23)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.gradle.wrapper.BootstrapMainStarter.start(BootstrapMainStarter.java:33)
        at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:130)
        at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:48)

> Task :Application:editorconfigCheck FAILED
ANTLR Tool version 4.7 used for code generation does not match the current runtime version 4.5.3ANTLR Runtime version 4.7 used for parser compilation does not match the current runtime version 4.5.3

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':Application:editorconfigCheck'.
> java.lang.ExceptionInInitializerError (no error message)

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

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':Application:editorconfigCheck'.
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)
        at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
        at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)
        at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
        at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:60)
        at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:97)
        at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:87)
        at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
        at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
        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$1.run(DefaultTaskGraphExecuter.java:248)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$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:241)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$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$1.execute(DefaultTaskPlanExecutor.java:98)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:626)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:581)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
        at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
        at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
        at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
Caused by: java.lang.ExceptionInInitializerError
        at org.ec4j.maven.linters.XmlLinter.process(XmlLinter.java:583)
        at org.ec4j.gradle.AbstractEditorconfigTask.perform(AbstractEditorconfigTask.java:176)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:46)
        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.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:780)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:747)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:121)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor$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:110)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92)
        ... 29 more
Caused by: java.lang.UnsupportedOperationException: java.io.InvalidClassException: org.antlr.v4.runtime.atn.ATN; Could not deserialize ATN with UUID 59627784-3be5-417a-b9eb-8131a7286089 (expected aadb8d7e-aeef-4415-ad2b-8204d6cf042e or a legacy UUID).
        at org.antlr.v4.runtime.atn.ATNDeserializer.deserialize(ATNDeserializer.java:153)
        at org.ec4j.maven.linters.xml.XmlParser.<clinit>(XmlParser.java:997)
        ... 44 more
Caused by: java.io.InvalidClassException: org.antlr.v4.runtime.atn.ATN; Could not deserialize ATN with UUID 59627784-3be5-417a-b9eb-8131a7286089 (expected aadb8d7e-aeef-4415-ad2b-8204d6cf042e or a legacy UUID).
        ... 46 more


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

BUILD FAILED in 4s
1 actionable task: 1 executed

The stack trace seems to suggest that the plugin is run with an improper antlr4-runtime version.

Question 1: How can I see the list of libs and their versions my plugin is run with? I tried googling but found only tips for inspecting the classpath of the code in the project that gradle is building. I found nothing for plugin maintainers.

Question 2: How can I figure out where is the bad version of antlr4-runtime coming from? Can I force gradle to use the version my plugin depends on for my plugin somehow?

Thanks

2

Run gradle buildEnvironment to see the buildscript dependencies.

Instead of making your plugin depend on ec4j, resolve ec4j via a Configuration and either fork it or load it into an isolated ClassLoader. You can see that in many of Gradle’s own plugins like the Checkstyle plugin where we load the Checkstyle library only when the task is executed.

3

Thanks Stefan, I kinda understand how your approach is supposed to work at runtime. But I fail to see in the Checkstyle example how should it be compiled.

When I remove org.ec4j.maven:ec4j-linters from build.gradle [1] the project does not compile because the compiler cannot find the classes from org.ec4j.maven:ec4j-linters or its transitive deps.

Should I maybe keep org.ec4j.maven:ec4j-linters in build.gradlebut change its scope from compile to compileOnly?

[1] https://github.com/ppalaga/editorconfig-gradle-plugin/commit/86dffa58acf31a63e9963f530fc444581aa8bf19

4

I think I figured out both the runtime and compile time mechanics for the Checkstyle Gradle plugin. The trick seems to be that the only class depending on the checkstyle lib is CheckstyleInvoker which is groovy and thus does not need to get compiled.

I see that at runtime the CheckstyleInvoker calls checkstyle via Ant using the custom classpath. Could you please give me a hint how to do the same without an ant task? I currently do not have an ant task for Editorconfig and I’d like to avoid implementing only because of this.

5

It looks like I can do roughly what org.gradle.api.internal.project.antbuilder.DefaultIsolatedAntBuilder.execute(Closure) is doing.

The question is still open whether I can have org.ec4j.maven:ec4j-linters as a compileOnly dependency of my plugin in build.gradle.

6

You can use the worker API and use ec4j as a compileOnly dependency, so you can compile the work item against it.

7

@st_oehme, thanks, the Worker API looked promising, but I could not get as far as wished. The main obstacle for me was that to submit my Runnable to WorkerExecutor.submit(Class<? extends Runnable>, Action<? super WorkerConfiguration>), I already need to have my Runnable class loaded.
My Runnable cannot be loaded unless the classes from my custom classpath are available. WorkerExecutor would be much useful for me if it was able to load the Runnable class itself (e.g. by name) using the custom classpath.

8

Your runnable should be part of your plugin. You just need to ensure it doesn’t reference types of the library you’ll call in its fields or any method parameters (otherwise the JVM will try and fail to load those).

9

Having to pass only Serializable params to WorkerConfiguration.params() is utterly impractical. I understand this is inevitable for IsolationMode.PROCESS but I wonder if it is technically necessary also for IsolationMode.CLASSLOADER?

10

In the end I was able to use the worker API. The result is pretty ugly mainly because the Runnable loaded by the isolated class loader did not log properly. My plugin is supposed to output messages to the log. That’s is important both for testing (check that the plugin actually checks also the files having no format violations) and for the users to actually see where the formatting violations are. I also found no simple way to send data back from the worker to the calling task. Hence I ended up misusing RuntimeException’s message field for sending the log messages from the worker back to the caller: https://github.com/ec4j/editorconfig-gradle-plugin/commit/9b6a019a1bac9ccfff91406f5f2c56adc25c1f62#diff-2a3a23b10435dd7c1c77f97e6ba98578R131
I am open for suggestions to improve that hacky solution.

The worker API makes an overall impression to be designed with different goals in mind than to offer a flawless classpath isolation for plugins. Too much overhead (Serializable params?!?!) is needed on the developer side to get such a basic thing working and still, the logging is broken.