"UncheckedIOException: Unable to store input properties" with RegularFileProperty

Hi. I’m migrating the old plugin gradle-pitest-plugin created in the times of Gradle 1.0 to the Provider/Property API and I wonder why I get:

UncheckedIOException: Unable to store input properties for task ‘:pitest’. Property ‘additionalClasspathFile’ with value ‘/home/…/build/pitClasspath’ cannot be serialized.

ClassCastException: class java.io.File cannot be cast to class java.lang.String (java.io.File and java.lang.String are in module java.base of loader ‘bootstrap’)

...
Caused by: org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':pitest'.
	at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:38)
	at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:77)
	at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:55)
	at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
	at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416)
	at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406)
	at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
	at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
	at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
	at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102)
	at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36)
	at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:52)
	at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:43)
	at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:355)
	at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:343)
	at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:336)
	at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:322)
	at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:134)
	at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:129)
	at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:202)
	at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:193)
	at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:129)
	... 3 more
Caused by: org.gradle.api.UncheckedIOException: Unable to store input properties for task ':pitest'. Property 'additionalClasspathFile' with value '/home/foobar/Code/gradle-pitest-plugin/build/nebulatest/info.solidsoft.gradle.pitest.functional.PitestPluginGradleVersionFunctionalSpec/should-run-mutation-analysis-with-Gradle-5-6-1/build/pitClasspath' cannot be serialized.
	at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.lambda$fingerprintInputProperties$2(CaptureStateBeforeExecutionStep.java:140)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution.visitInputProperties(ExecuteActionsTaskExecuter.java:266)
	at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.fingerprintInputProperties(CaptureStateBeforeExecutionStep.java:131)
	at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.createExecutionState(CaptureStateBeforeExecutionStep.java:113)
	at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.execute(CaptureStateBeforeExecutionStep.java:67)
	at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.execute(CaptureStateBeforeExecutionStep.java:47)
	at org.gradle.internal.execution.impl.DefaultWorkExecutor.execute(DefaultWorkExecutor.java:33)
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:140)
	at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:62)
	at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:108)
	at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute(ResolveBeforeExecutionOutputsTaskExecuter.java:67)
	at org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute(ResolveAfterPreviousExecutionStateTaskExecuter.java:46)
	at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:94)
	at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
	at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:95)
	at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57)
	at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56)
	at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36)
	... 24 more
Caused by: java.lang.ClassCastException: class java.io.File cannot be cast to class java.lang.String (java.io.File and java.lang.String are in module java.base of loader 'bootstrap')
	at org.gradle.internal.snapshot.impl.DefaultValueSnapshotter$ValueSnapshotVisitor.managedImmutableValue(DefaultValueSnapshotter.java:283)
	at org.gradle.internal.snapshot.impl.DefaultValueSnapshotter$ValueSnapshotVisitor.managedImmutableValue(DefaultValueSnapshotter.java:224)
	at org.gradle.internal.snapshot.impl.DefaultValueSnapshotter.processValue(DefaultValueSnapshotter.java:151)
	at org.gradle.internal.snapshot.impl.DefaultValueSnapshotter.snapshot(DefaultValueSnapshotter.java:53)
	at org.gradle.internal.execution.steps.CaptureStateBeforeExecutionStep.lambda$fingerprintInputProperties$2(CaptureStateBeforeExecutionStep.java:135)
	... 41 more

for the following code:

@CompileStatic
class PitestTask extends JavaExec {

    @Input
    @OutputFile
    final RegularFileProperty additionalClasspathFile
...
}
task.additionalClasspathFile.set(project.layout.buildDirectory.file("anything"))

Gradle 5.6.1.

How can I set RegularFileProperty to some custom value?

Guys, can I do it in some other way, or it is a bug and I should report it for reference?

When something explodes inside the “internal” package, that sounds like a bug to me.

That being said, I don’t think it makes sense to have both @Input and @OutputFile on the same property and maybe that’s what causing the issue.

Actually, the problem happens because @Input doesn’t work on a RegularFileProvider. However, @InputFile works.

Still a bug IMHO.

I use additionalClasspathFile as @Input to point out that name (location) is important as an input (not its content) and as @OutputFile as my tasks generates that file. I could split it into 2 properties, but it would be an artificial division (just a workaround).

Reported as: https://github.com/gradle/gradle/issues/10690

Ah, makes sense then :slight_smile:

Why do you need the output file name as input though?
If it is for up-to-date checks, this shouldn’t be necessary, is it?
If the output file changes, between runs, the task is considered out-of-date already.