Gradle build improperly fails with "cannot mutate dependencies of configuration ':runtimeOnly'"

[anelosima]

I am attempting to load the project https://github.com/FAForever/downlords-faf-client.

Expected Behavior

The project properly builds.

Current Behavior

An error occurs: The supplied phased action failed with an exception. Could not create task ':fx2jJar'. Cannot mutate the dependencies of configuration ':runtimeOnly' after the configuration's child configuration ':runtimeClasspath' was resolved. After a configuration has been observed, it should not be modified.

With stack trace:

org.gradle.tooling.BuildActionFailureException: The supplied phased action failed with an exception. at org.gradle.tooling.internal.consumer.connection.PhasedActionAwareConsumerConnection.run(PhasedActionAwareConsumerConnection.java:58) at org.gradle.tooling.internal.consumer.connection.ParameterValidatingConsumerConnection.run(ParameterValidatingConsumerConnection.java:62) at org.gradle.tooling.internal.consumer.DefaultPhasedBuildActionExecuter$1.run(DefaultPhasedBuildActionExecuter.java:83) at org.gradle.tooling.internal.consumer.DefaultPhasedBuildActionExecuter$1.run(DefaultPhasedBuildActionExecuter.java:75) at org.gradle.tooling.internal.consumer.connection.LazyConsumerActionExecutor.run(LazyConsumerActionExecutor.java:143) at org.gradle.tooling.internal.consumer.connection.CancellableConsumerActionExecutor.run(CancellableConsumerActionExecutor.java:45) at org.gradle.tooling.internal.consumer.connection.ProgressLoggingConsumerActionExecutor.run(ProgressLoggingConsumerActionExecutor.java:61) at org.gradle.tooling.internal.consumer.connection.RethrowingErrorsConsumerActionExecutor.run(RethrowingErrorsConsumerActionExecutor.java:38) at org.gradle.tooling.internal.consumer.async.DefaultAsyncConsumerActionExecutor$1$1.run(DefaultAsyncConsumerActionExecutor.java:66) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64) at org.gradle.internal.concurrent.AbstractManagedExecutor$1.run(AbstractManagedExecutor.java:48) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) at java.base/java.lang.Thread.run(Thread.java:1583) at org.gradle.tooling.internal.consumer.BlockingResultHandler.getResult(BlockingResultHandler.java:46) at org.gradle.tooling.internal.consumer.DefaultPhasedBuildActionExecuter.run(DefaultPhasedBuildActionExecuter.java:68) at org.gradle.tooling.internal.consumer.DefaultPhasedBuildActionExecuter.run(DefaultPhasedBuildActionExecuter.java:31) at org.eclipse.buildship.core.internal.workspace.EclipseModelUtils.runPhasedModelQuery(EclipseModelUtils.java:111) at org.eclipse.buildship.core.internal.workspace.EclipseModelUtils.runTasksAndQueryCompositeModelWithRuntimInfo(EclipseModelUtils.java:86) at org.eclipse.buildship.core.internal.workspace.EclipseModelUtils.runTasksAndQueryModels(EclipseModelUtils.java:60) at org.eclipse.buildship.core.internal.workspace.DefaultModelProvider.lambda$fetchEclipseProjectAndRunSyncTasks$4(DefaultModelProvider.java:75) at org.eclipse.buildship.core.internal.DefaultGradleBuild$GradleConnectionOperation.runInToolingApi(DefaultGradleBuild.java:337) at org.eclipse.buildship.core.internal.operation.DefaultToolingApiOperationManager$WorkspaceRunnableAdapter.run(DefaultToolingApiOperationManager.java:58) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2505) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2533) at org.eclipse.buildship.core.internal.operation.DefaultToolingApiOperationManager.run(DefaultToolingApiOperationManager.java:39) at org.eclipse.buildship.core.internal.DefaultGradleBuild.withConnection(DefaultGradleBuild.java:127) at org.eclipse.buildship.core.internal.workspace.DefaultModelProvider.lambda$fetchEclipseProjectAndRunSyncTasks$5(DefaultModelProvider.java:75) at com.google.common.cache.LocalCache$LocalManualCache$1.load(LocalCache.java:4860) at com.google.common.cache.LocalCache$LoadingValueReference.loadFuture(LocalCache.java:3551) at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2302) at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2177) at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2068) at com.google.common.cache.LocalCache.get(LocalCache.java:3986) at com.google.common.cache.LocalCache$LocalManualCache.get(LocalCache.java:4855) at org.eclipse.buildship.core.internal.workspace.DefaultModelProvider.getFromCache(DefaultModelProvider.java:98) at org.eclipse.buildship.core.internal.workspace.DefaultModelProvider.executeOperation(DefaultModelProvider.java:90) at org.eclipse.buildship.core.internal.workspace.DefaultModelProvider.fetchEclipseProjectAndRunSyncTasks(DefaultModelProvider.java:72) at org.eclipse.buildship.core.internal.DefaultGradleBuild$SynchronizeOperation.runInToolingApi(DefaultGradleBuild.java:234) at org.eclipse.buildship.core.internal.operation.DefaultToolingApiOperationManager$WorkspaceRunnableAdapter.run(DefaultToolingApiOperationManager.java:58) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2505) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2533) at org.eclipse.buildship.core.internal.operation.DefaultToolingApiOperationManager.run(DefaultToolingApiOperationManager.java:39) at org.eclipse.buildship.core.internal.DefaultGradleBuild$SynchronizeOperation.run(DefaultGradleBuild.java:197) at org.eclipse.buildship.core.internal.DefaultGradleBuild.synchronize(DefaultGradleBuild.java:105) at org.eclipse.buildship.core.internal.workspace.SynchronizationJob.runInToolingApi(SynchronizationJob.java:64) at org.eclipse.buildship.core.internal.workspace.SynchronizationJob.runInToolingApi(SynchronizationJob.java:30) at org.eclipse.buildship.core.internal.operation.ToolingApiJob$1.runInToolingApi(ToolingApiJob.java:54) at org.eclipse.buildship.core.internal.operation.DefaultToolingApiOperationManager$WorkspaceRunnableAdapter.run(DefaultToolingApiOperationManager.java:58) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2505) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2533) at org.eclipse.buildship.core.internal.operation.DefaultToolingApiOperationManager.run(DefaultToolingApiOperationManager.java:39) at org.eclipse.buildship.core.internal.operation.ToolingApiJob.run(ToolingApiJob.java:65) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63) Caused by: org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreationException: Could not create task ':fx2jJar'. at org.gradle.api.internal.tasks.DefaultTaskContainer.taskCreationException(DefaultTaskContainer.java:729) at org.gradle.api.internal.tasks.DefaultTaskContainer.access$600(DefaultTaskContainer.java:78) at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.domainObjectCreationException(DefaultTaskContainer.java:721) at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.tryCreate(DefaultNamedDomainObjectCollection.java:1016) at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.access$1401(DefaultTaskContainer.java:668) at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider$1.run(DefaultTaskContainer.java:694) at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29) at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47) at org.gradle.api.internal.tasks.DefaultTaskContainer$TaskCreatingProvider.tryCreate(DefaultTaskContainer.java:690) at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.calculateOwnValue(DefaultNamedDomainObjectCollection.java:990) at org.gradle.api.internal.provider.AbstractMinimalProvider.getOrNull(AbstractMinimalProvider.java:105) at org.gradle.api.internal.DefaultNamedDomainObjectCollection.findByName(DefaultNamedDomainObjectCollection.java:323) at org.gradle.api.internal.tasks.DefaultTaskContainer.findByName(DefaultTaskContainer.java:572) at org.gradle.api.internal.tasks.DefaultTaskContainer.findByName(DefaultTaskContainer.java:77) at org.gradle.plugins.ide.internal.tooling.GradleProjectBuilder.collectTasks(GradleProjectBuilder.java:99) at org.gradle.plugins.ide.internal.tooling.GradleProjectBuilder.lambda$buildHierarchy$1(GradleProjectBuilder.java:83) at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.fromMutableState(DefaultProjectStateRegistry.java:460) at org.gradle.plugins.ide.internal.tooling.GradleProjectBuilder.buildHierarchy(GradleProjectBuilder.java:82) at org.gradle.plugins.ide.internal.tooling.GradleProjectBuilder.buildForRoot(GradleProjectBuilder.java:53) at org.gradle.plugins.ide.internal.tooling.EclipseModelBuilder.buildAll(EclipseModelBuilder.java:152) at org.gradle.plugins.ide.internal.tooling.EclipseModelBuilder.buildAll(EclipseModelBuilder.java:131) at org.gradle.plugins.ide.internal.tooling.EclipseModelBuilder.buildAll(EclipseModelBuilder.java:90) at org.gradle.tooling.provider.model.internal.DefaultToolingModelBuilderRegistry$BuilderWithParameter.build(DefaultToolingModelBuilderRegistry.java:293) at org.gradle.tooling.provider.model.internal.DefaultToolingModelBuilderRegistry$LockSingleProjectBuilder.lambda$build$0(DefaultToolingModelBuilderRegistry.java:308) at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.lambda$fromMutableState$2(DefaultProjectStateRegistry.java:465) at org.gradle.internal.work.DefaultWorkerLeaseService.withReplacedLocks(DefaultWorkerLeaseService.java:359) at org.gradle.api.internal.project.DefaultProjectStateRegistry$ProjectStateImpl.fromMutableState(DefaultProjectStateRegistry.java:465) at org.gradle.tooling.provider.model.internal.DefaultToolingModelBuilderRegistry$LockSingleProjectBuilder.build(DefaultToolingModelBuilderRegistry.java:308) at org.gradle.tooling.provider.model.internal.DefaultToolingModelBuilderRegistry$BuildOperationWrappingBuilder$1.call(DefaultToolingModelBuilderRegistry.java:341) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:209) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53) at org.gradle.tooling.provider.model.internal.DefaultToolingModelBuilderRegistry$BuildOperationWrappingBuilder.build(DefaultToolingModelBuilderRegistry.java:338) at org.gradle.internal.build.DefaultBuildToolingModelController$AbstractToolingScope.getModel(DefaultBuildToolingModelController.java:87) at org.gradle.internal.buildtree.DefaultBuildTreeModelCreator$DefaultBuildTreeModelController.getModelForScope(DefaultBuildTreeModelCreator.java:148) at org.gradle.internal.buildtree.DefaultBuildTreeModelCreator$DefaultBuildTreeModelController.access$300(DefaultBuildTreeModelCreator.java:70) at org.gradle.internal.buildtree.DefaultBuildTreeModelCreator$DefaultBuildTreeModelController$1.call(DefaultBuildTreeModelCreator.java:86) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:209) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53) at org.gradle.internal.buildtree.DefaultBuildTreeModelCreator$DefaultBuildTreeModelController.getModel(DefaultBuildTreeModelCreator.java:81) at org.gradle.tooling.internal.provider.runner.DefaultBuildController.getModel(DefaultBuildController.java:104) at org.gradle.tooling.internal.consumer.connection.ParameterAwareBuildControllerAdapter.getModel(ParameterAwareBuildControllerAdapter.java:40) at org.gradle.tooling.internal.consumer.connection.UnparameterizedBuildController.getModel(UnparameterizedBuildController.java:116) at org.gradle.tooling.internal.consumer.connection.NestedActionAwareBuildControllerAdapter.getModel(NestedActionAwareBuildControllerAdapter.java:32) at org.eclipse.buildship.core.internal.workspace.CompositeModelQuery.collectRootModels(CompositeModelQuery.java:62) at org.eclipse.buildship.core.internal.workspace.CompositeModelQuery.execute(CompositeModelQuery.java:52) at org.eclipse.buildship.core.internal.workspace.CompositeModelQuery.execute(CompositeModelQuery.java:28) at org.gradle.tooling.internal.consumer.connection.InternalBuildActionAdapter.execute(InternalBuildActionAdapter.java:65) at org.gradle.tooling.internal.provider.runner.AbstractClientProvidedBuildActionRunner$ActionAdapter.executeAction(AbstractClientProvidedBuildActionRunner.java:108) at org.gradle.tooling.internal.provider.runner.AbstractClientProvidedBuildActionRunner$ActionAdapter.runAction(AbstractClientProvidedBuildActionRunner.java:96) at org.gradle.tooling.internal.provider.runner.AbstractClientProvidedBuildActionRunner$ActionAdapter.fromBuildModel(AbstractClientProvidedBuildActionRunner.java:85) at org.gradle.tooling.internal.provider.runner.AbstractClientProvidedBuildActionRunner$ActionAdapter.fromBuildModel(AbstractClientProvidedBuildActionRunner.java:68) at org.gradle.internal.buildtree.DefaultBuildTreeModelCreator.fromBuildModel(DefaultBuildTreeModelCreator.java:67) at org.gradle.internal.cc.impl.barrier.BarrierAwareBuildTreeModelCreator.fromBuildModel$lambda$1(BarrierAwareBuildTreeModelCreator.kt:36) at org.gradle.internal.cc.impl.barrier.VintageConfigurationTimeActionRunner.runConfigurationTimeAction(VintageConfigurationTimeActionRunner.kt:48) at org.gradle.internal.cc.impl.barrier.BarrierAwareBuildTreeModelCreator.fromBuildModel(BarrierAwareBuildTreeModelCreator.kt:35) at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$fromBuildModel$2(DefaultBuildTreeLifecycleController.java:90) at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.lambda$runBuild$4(DefaultBuildTreeLifecycleController.java:120) at org.gradle.internal.model.StateTransitionController.lambda$transition$6(StateTransitionController.java:169) at org.gradle.internal.model.StateTransitionController.doTransition(StateTransitionController.java:266) at org.gradle.internal.model.StateTransitionController.lambda$transition$7(StateTransitionController.java:169) at org.gradle.internal.work.DefaultSynchronizer.withLock(DefaultSynchronizer.java:45) at org.gradle.internal.model.StateTransitionController.transition(StateTransitionController.java:169) at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.runBuild(DefaultBuildTreeLifecycleController.java:117) at org.gradle.internal.buildtree.DefaultBuildTreeLifecycleController.fromBuildModel(DefaultBuildTreeLifecycleController.java:82) at org.gradle.tooling.internal.provider.runner.AbstractClientProvidedBuildActionRunner.runClientAction(AbstractClientProvidedBuildActionRunner.java:42) at org.gradle.tooling.internal.provider.runner.ClientProvidedPhasedActionRunner.run(ClientProvidedPhasedActionRunner.java:58) at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35) at org.gradle.internal.buildtree.ProblemReportingBuildActionRunner.run(ProblemReportingBuildActionRunner.java:54) at org.gradle.launcher.exec.BuildOutcomeReportingBuildActionRunner.run(BuildOutcomeReportingBuildActionRunner.java:83) at org.gradle.tooling.internal.provider.FileSystemWatchingBuildActionRunner.run(FileSystemWatchingBuildActionRunner.java:135) at org.gradle.launcher.exec.BuildCompletionNotifyingBuildActionRunner.run(BuildCompletionNotifyingBuildActionRunner.java:54) at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.lambda$execute$0(RootBuildLifecycleBuildActionExecutor.java:56) at org.gradle.composite.internal.DefaultRootBuildState.run(DefaultRootBuildState.java:131) at org.gradle.launcher.exec.RootBuildLifecycleBuildActionExecutor.execute(RootBuildLifecycleBuildActionExecutor.java:56) at org.gradle.internal.buildtree.InitDeprecationLoggingActionExecutor.execute(InitDeprecationLoggingActionExecutor.java:62) at org.gradle.internal.buildtree.InitProblems.execute(InitProblems.java:36) at org.gradle.internal.buildtree.DefaultBuildTreeContext.execute(DefaultBuildTreeContext.java:40) at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.lambda$execute$0(BuildTreeLifecycleBuildActionExecutor.java:71) at org.gradle.internal.buildtree.BuildTreeState.run(BuildTreeState.java:60) at org.gradle.launcher.exec.BuildTreeLifecycleBuildActionExecutor.execute(BuildTreeLifecycleBuildActionExecutor.java:71) at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$2.call(RunAsBuildOperationBuildActionExecutor.java:65) at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor$2.call(RunAsBuildOperationBuildActionExecutor.java:61) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:209) at org.gradle.internal.operations.DefaultBuildOperationRunner$CallableBuildOperationWorker.execute(DefaultBuildOperationRunner.java:204) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.call(DefaultBuildOperationRunner.java:53) at org.gradle.launcher.exec.RunAsBuildOperationBuildActionExecutor.execute(RunAsBuildOperationBuildActionExecutor.java:61) at org.gradle.launcher.exec.RunAsWorkerThreadBuildActionExecutor.lambda$execute$0(RunAsWorkerThreadBuildActionExecutor.java:36) at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:263) at org.gradle.internal.work.DefaultWorkerLeaseService.runAsWorkerThread(DefaultWorkerLeaseService.java:127) at org.gradle.launcher.exec.RunAsWorkerThreadBuildActionExecutor.execute(RunAsWorkerThreadBuildActionExecutor.java:36) at org.gradle.tooling.internal.provider.continuous.ContinuousBuildActionExecutor.execute(ContinuousBuildActionExecutor.java:110) at org.gradle.tooling.internal.provider.SubscribableBuildActionExecutor.execute(SubscribableBuildActionExecutor.java:64) at org.gradle.internal.session.DefaultBuildSessionContext.execute(DefaultBuildSessionContext.java:46) at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor$ActionImpl.apply(BuildSessionLifecycleBuildActionExecutor.java:92) at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor$ActionImpl.apply(BuildSessionLifecycleBuildActionExecutor.java:80) at org.gradle.internal.session.BuildSessionState.run(BuildSessionState.java:73) at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor.execute(BuildSessionLifecycleBuildActionExecutor.java:62) at org.gradle.internal.buildprocess.execution.BuildSessionLifecycleBuildActionExecutor.execute(BuildSessionLifecycleBuildActionExecutor.java:41) at org.gradle.internal.buildprocess.execution.StartParamsValidatingActionExecutor.execute(StartParamsValidatingActionExecutor.java:57) at org.gradle.internal.buildprocess.execution.StartParamsValidatingActionExecutor.execute(StartParamsValidatingActionExecutor.java:32) at org.gradle.internal.buildprocess.execution.SessionFailureReportingActionExecutor.execute(SessionFailureReportingActionExecutor.java:51) at org.gradle.internal.buildprocess.execution.SessionFailureReportingActionExecutor.execute(SessionFailureReportingActionExecutor.java:39) at org.gradle.internal.buildprocess.execution.SetupLoggingActionExecutor.execute(SetupLoggingActionExecutor.java:47) at org.gradle.internal.buildprocess.execution.SetupLoggingActionExecutor.execute(SetupLoggingActionExecutor.java:31) at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:70) at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:39) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:29) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:35) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.ForwardClientInput.lambda$execute$0(ForwardClientInput.java:40) at org.gradle.internal.daemon.clientinput.ClientInputForwarder.forwardInput(ClientInputForwarder.java:80) at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:37) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:64) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:63) at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:84) at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:37) at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:104) at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:52) at org.gradle.launcher.daemon.server.DaemonStateCoordinator.lambda$runCommand$0(DaemonStateCoordinator.java:321) at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64) at org.gradle.internal.concurrent.AbstractManagedExecutor$1.run(AbstractManagedExecutor.java:47) Caused by: org.gradle.api.InvalidUserCodeException: Cannot mutate the dependencies of configuration ':runtimeOnly' after the configuration's child configuration ':runtimeClasspath' was resolved. After a configuration has been observed, it should not be modified. at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration.validateMutation(DefaultConfiguration.java:1229) at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration.lambda$validateMutationType$0(DefaultConfiguration.java:319) at org.gradle.internal.ImmutableActionSet$SingletonSet.execute(ImmutableActionSet.java:226) at org.gradle.api.internal.DefaultDomainObjectCollection.assertCanMutate(DefaultDomainObjectCollection.java:453) at org.gradle.api.internal.DefaultDomainObjectCollection.add(DefaultDomainObjectCollection.java:273) at org.gradle.api.internal.DelegatingDomainObjectSet.add(DelegatingDomainObjectSet.java:115) at org.gradle.api.internal.artifacts.DefaultDependencySet.add(DefaultDependencySet.java:68) at org.gradle.api.internal.artifacts.DefaultDependencySet.add(DefaultDependencySet.java:35) at org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.doAddRegularDependency(DefaultDependencyHandler.java:198) at org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.doAdd(DefaultDependencyHandler.java:192) at org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.add(DefaultDependencyHandler.java:120) at org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.add(DefaultDependencyHandler.java:114) at io.github.sheikah45.fx2j.gradle.plugin.Fx2jPlugin.lambda$apply$6(Fx2jPlugin.java:99) at org.gradle.api.internal.DefaultMutationGuard$1.execute(DefaultMutationGuard.java:66) at org.gradle.api.internal.DefaultMutationGuard$1.execute(DefaultMutationGuard.java:66) at org.gradle.internal.code.DefaultUserCodeApplicationContext$CurrentApplication$1.execute(DefaultUserCodeApplicationContext.java:124) at org.gradle.api.internal.DefaultCollectionCallbackActionDecorator$BuildOperationEmittingAction$1.run(DefaultCollectionCallbackActionDecorator.java:109) at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:29) at org.gradle.internal.operations.DefaultBuildOperationRunner$1.execute(DefaultBuildOperationRunner.java:26) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:66) at org.gradle.internal.operations.DefaultBuildOperationRunner$2.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:166) at org.gradle.internal.operations.DefaultBuildOperationRunner.execute(DefaultBuildOperationRunner.java:59) at org.gradle.internal.operations.DefaultBuildOperationRunner.run(DefaultBuildOperationRunner.java:47) at org.gradle.api.internal.DefaultCollectionCallbackActionDecorator$BuildOperationEmittingAction.execute(DefaultCollectionCallbackActionDecorator.java:106) at org.gradle.internal.ImmutableActionSet$SetWithManyActions.execute(ImmutableActionSet.java:330) at org.gradle.api.internal.DefaultDomainObjectCollection.doAdd(DefaultDomainObjectCollection.java:280) at org.gradle.api.internal.DefaultNamedDomainObjectCollection.doAdd(DefaultNamedDomainObjectCollection.java:126) at org.gradle.api.internal.DefaultNamedDomainObjectCollection$AbstractDomainObjectCreatingProvider.tryCreate(DefaultNamedDomainObjectCollection.java:1010) ... 144 more

Context

I believe that this error is due to buildship (rather than an issue with the project being built) since building the project using the Gradle CLI works without issue; running each individual task through Gradle directly also works. The project also builds successfully in IntelliJ.

Steps to Reproduce

Download and attempt to build https://github.com/FAForever/downlords-faf-client. The project is very large and producing a minimal working example would be challenging; if it would be helpful, I can do so.

Your Environment

Originally encountered the error using the Eclipse JDTLS with Emacs lsp-mode; the Eclipse IDE produces the same error.