Compile dependency on artifact with classifier throws NPE

Hi.

If I express a dependency with a Maven classifier like this

compile group: "com.example.ocb", name: "ocb", version: project.theVersion, classifier: "classes" {
   // transitive = false
}

then gradle throws an NPE when trying to resolve the depedency:

:clean UP-TO-DATE
:automated-testing-framework:clean UP-TO-DATE
:testng-support:clean
:testng-support:compileJava
:testng-support:processResources UP-TO-DATE
:testng-support:classes
:testng-support:jar
:automated-testing-framework:compileJava
  FAILURE: Build failed with an exception.
  * What went wrong:
Could not resolve all dependencies for configuration ':automated-testing-framework:compile'.
> Could not download artifact 'com.example.ocb:ocb:9.7-SNAPSHOT:task ':automated-testing-framework:classes'@jar'
   > java.lang.NullPointerException (no error message)
  * Try:
Run with --info or --debug option to get more log output.
  * Exception is:
org.gradle.api.artifacts.ResolveException: Could not resolve all dependencies for configuration ':automated-testing-framework:compile'.
 at org.gradle.api.internal.artifacts.ivyservice.ErrorHandlingArtifactDependencyResolver.wrapException(ErrorHandlingArtifactDependencyResolver.java:48)
 at org.gradle.api.internal.artifacts.ivyservice.ErrorHandlingArtifactDependencyResolver.access$000(ErrorHandlingArtifactDependencyResolver.java:27)
 at org.gradle.api.internal.artifacts.ivyservice.ErrorHandlingArtifactDependencyResolver$ErrorHandlingResolvedConfiguration.getFiles(ErrorHandlingArtifactDependencyResolver.java:81)
 at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration$ConfigurationFileCollection.getFiles(DefaultConfiguration.java:460)
 at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration.getFiles(DefaultConfiguration.java:203)
 at org.gradle.api.internal.artifacts.configurations.DefaultConfiguration_Decorated.getFiles(Unknown Source)
 at org.gradle.api.internal.file.collections.DefaultFileCollectionResolveContext$FileTreeConverter.convertInto(DefaultFileCollectionResolveContext.java:191)
 at org.gradle.api.internal.file.collections.DefaultFileCollectionResolveContext.doResolve(DefaultFileCollectionResolveContext.java:103)
 at org.gradle.api.internal.file.collections.DefaultFileCollectionResolveContext.resolveAsFileTrees(DefaultFileCollectionResolveContext.java:75)
 at org.gradle.api.internal.file.collections.DefaultFileCollectionResolveContext$FileTreeConverter.convertInto(DefaultFileCollectionResolveContext.java:182)
 at org.gradle.api.internal.file.collections.DefaultFileCollectionResolveContext.doResolve(DefaultFileCollectionResolveContext.java:98)
 at org.gradle.api.internal.file.collections.DefaultFileCollectionResolveContext.resolveAsFileTrees(DefaultFileCollectionResolveContext.java:75)
 at org.gradle.api.internal.file.CompositeFileCollection$1.resolve(CompositeFileCollection.java:88)
 at org.gradle.api.internal.file.CompositeFileCollection.getSourceCollections(CompositeFileCollection.java:143)
 at org.gradle.api.internal.file.CompositeFileTree.getSourceCollections(CompositeFileTree.java:30)
 at org.gradle.api.internal.file.CompositeFileCollection.getFiles(CompositeFileCollection.java:38)
 at org.gradle.api.internal.file.AbstractFileCollection.iterator(AbstractFileCollection.java:60)
 at org.gradle.api.internal.changedetection.DefaultFileSnapshotter.snapshot(DefaultFileSnapshotter.java:42)
 at org.gradle.api.internal.changedetection.InputFilesChangedUpToDateRule.create(InputFilesChangedUpToDateRule.java:35)
 at org.gradle.api.internal.changedetection.CompositeUpToDateRule.create(CompositeUpToDateRule.java:35)
 at org.gradle.api.internal.changedetection.DefaultTaskArtifactStateRepository$HistoricExecution.calcCurrentState(DefaultTaskArtifactStateRepository.java:80)
 at org.gradle.api.internal.changedetection.DefaultTaskArtifactStateRepository$HistoricExecution.isUpToDate(DefaultTaskArtifactStateRepository.java:88)
 at org.gradle.api.internal.changedetection.DefaultTaskArtifactStateRepository$TaskArtifactStateImpl.isUpToDate(DefaultTaskArtifactStateRepository.java:128)
 at org.gradle.api.internal.changedetection.ShortCircuitTaskArtifactStateRepository$ShortCircuitArtifactState.isUpToDate(ShortCircuitTaskArtifactStateRepository.java:77)
 at org.gradle.api.internal.changedetection.FileCacheBroadcastTaskArtifactStateRepository$1.isUpToDate(FileCacheBroadcastTaskArtifactStateRepository.java:37)
 at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:44)
 at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:57)
 at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:41)
 at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:51)
 at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:52)
 at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:42)
 at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:247)
 at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.executeTask(DefaultTaskPlanExecutor.java:52)
 at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.processTask(DefaultTaskPlanExecutor.java:38)
 at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:30)
 at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:83)
 at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:29)
 at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:61)
 at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23)
 at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:67)
 at org.gradle.api.internal.changedetection.TaskCacheLockHandlingBuildExecuter$1.run(TaskCacheLockHandlingBuildExecuter.java:31)
 at org.gradle.cache.internal.DefaultCacheAccess$2.create(DefaultCacheAccess.java:118)
 at org.gradle.cache.internal.DefaultCacheAccess.useCache(DefaultCacheAccess.java:133)
 at org.gradle.cache.internal.DefaultCacheAccess.useCache(DefaultCacheAccess.java:116)
 at org.gradle.cache.internal.DefaultPersistentDirectoryStore.useCache(DefaultPersistentDirectoryStore.java:129)
 at org.gradle.api.internal.changedetection.DefaultTaskArtifactStateCacheAccess.useCache(DefaultTaskArtifactStateCacheAccess.java:79)
 at org.gradle.api.internal.changedetection.TaskCacheLockHandlingBuildExecuter.execute(TaskCacheLockHandlingBuildExecuter.java:29)
 at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:61)
 at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23)
 at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:67)
 at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
 at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:61)
 at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:54)
 at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:158)
 at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradleLauncher.java:113)
 at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:81)
 at org.gradle.launcher.cli.ExecuteBuildAction.run(ExecuteBuildAction.java:38)
 at org.gradle.launcher.exec.InProcessGradleLauncherActionExecuter.execute(InProcessGradleLauncherActionExecuter.java:39)
 at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:45)
 at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:42)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:24)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.StartStopIfBuildAndStop.execute(StartStopIfBuildAndStop.java:33)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.ReturnResult.execute(ReturnResult.java:34)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:70)
 at org.gradle.launcher.daemon.server.exec.ForwardClientInput$2.call(ForwardClientInput.java:68)
 at org.gradle.util.Swapper.swap(Swapper.java:38)
 at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:68)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:60)
 at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:61)
 at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy$1.run(StartBuildOrRespondWithBusy.java:45)
 at org.gradle.launcher.daemon.server.DaemonStateCoordinator.runCommand(DaemonStateCoordinator.java:185)
 at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy.doBuild(StartBuildOrRespondWithBusy.java:49)
 at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:34)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.HandleStop.execute(HandleStop.java:36)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.CatchAndForwardDaemonFailure.execute(CatchAndForwardDaemonFailure.java:32)
 at org.gradle.launcher.daemon.server.exec.DaemonCommandExecution.proceed(DaemonCommandExecution.java:126)
 at org.gradle.launcher.daemon.server.exec.DefaultDaemonCommandExecuter.executeCommand(DefaultDaemonCommandExecuter.java:52)
 at org.gradle.launcher.daemon.server.DefaultIncomingConnectionHandler$ConnectionWorker.handleCommand(DefaultIncomingConnectionHandler.java:142)
 at org.gradle.launcher.daemon.server.DefaultIncomingConnectionHandler$ConnectionWorker.run(DefaultIncomingConnectionHandler.java:116)
 at org.gradle.internal.concurrent.DefaultExecutorFactory$StoppableExecutorImpl$1.run(DefaultExecutorFactory.java:66)
Caused by: org.gradle.api.internal.artifacts.ivyservice.ivyresolve.ArtifactResolveException: Could not download artifact 'com.example.ocb:ocb:9.7-SNAPSHOT:task ':automated-testing-framework:classes'@jar'
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.LazyDependencyToModuleResolver$ErrorHandlingArtifactResolver.resolve(LazyDependencyToModuleResolver.java:61)
 at org.gradle.api.internal.artifacts.ivyservice.ResolvedArtifactFactory$1$1.create(ResolvedArtifactFactory.java:38)
 at org.gradle.api.internal.artifacts.ivyservice.ResolvedArtifactFactory$1$1.create(ResolvedArtifactFactory.java:36)
 at org.gradle.cache.internal.DefaultCacheAccess.useCache(DefaultCacheAccess.java:133)
 at org.gradle.cache.internal.DefaultPersistentDirectoryStore.useCache(DefaultPersistentDirectoryStore.java:125)
 at org.gradle.api.internal.artifacts.ivyservice.DefaultCacheLockingManager.useCache(DefaultCacheLockingManager.java:49)
 at org.gradle.api.internal.artifacts.ivyservice.ResolvedArtifactFactory$1.create(ResolvedArtifactFactory.java:36)
 at org.gradle.api.internal.artifacts.ivyservice.ResolvedArtifactFactory$1.create(ResolvedArtifactFactory.java:34)
 at org.gradle.api.internal.artifacts.DefaultResolvedArtifact.getFile(DefaultResolvedArtifact.java:117)
 at org.gradle.api.internal.artifacts.ivyservice.DefaultLenientConfiguration.getFiles(DefaultLenientConfiguration.java:126)
 at org.gradle.api.internal.artifacts.ivyservice.DefaultLenientConfiguration.getFilesStrict(DefaultLenientConfiguration.java:101)
 at org.gradle.api.internal.artifacts.ivyservice.DefaultResolvedConfiguration.getFiles(DefaultResolvedConfiguration.java:48)
 at org.gradle.api.internal.artifacts.ivyservice.SelfResolvingDependencyResolver$1.getFiles(SelfResolvingDependencyResolver.java:57)
 at org.gradle.api.internal.artifacts.ivyservice.ErrorHandlingArtifactDependencyResolver$ErrorHandlingResolvedConfiguration.getFiles(ErrorHandlingArtifactDependencyResolver.java:79)
 ... 90 more
Caused by: java.lang.NullPointerException
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.DependencyResolverAdapter.downloadFailed(DependencyResolverAdapter.java:95)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.DependencyResolverAdapter.download(DependencyResolverAdapter.java:71)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CacheLockingModuleVersionRepository$2.create(CacheLockingModuleVersionRepository.java:59)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CacheLockingModuleVersionRepository$2.create(CacheLockingModuleVersionRepository.java:57)
 at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:188)
 at org.gradle.cache.internal.DefaultPersistentDirectoryStore.longRunningOperation(DefaultPersistentDirectoryStore.java:133)
 at org.gradle.api.internal.artifacts.ivyservice.DefaultCacheLockingManager.longRunningOperation(DefaultCacheLockingManager.java:57)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CacheLockingModuleVersionRepository.download(CacheLockingModuleVersionRepository.java:57)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.CachingModuleVersionRepository.download(CachingModuleVersionRepository.java:221)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.IvyContextualiser$1.invoke(IvyContextualiser.java:44)
 at $Proxy36.download(Unknown Source)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.UserResolverChain$ModuleVersionRepositoryBackedArtifactResolver.resolve(UserResolverChain.java:163)
 at org.gradle.api.internal.artifacts.ivyservice.ivyresolve.LazyDependencyToModuleResolver$ErrorHandlingArtifactResolver.resolve(LazyDependencyToModuleResolver.java:59)
 ... 103 more
    BUILD FAILED
  Total time: 1.478 secs

If I express the dependency like this

compile group: "com.example.ocb", name: "ocb", version: project.theVersion, classifier: "classes"

no NPE is thrown.

Took me a while to figure out what was going on.

Can one not have an empty config block for dependencies with classifiers?

Thanks.