@Classpath and up-to-date

Help/Discuss
1

I have the following task, which is never up-to-date:

@CacheableTask
public abstract class VerifyDependenciesTask extends DefaultTask {
	private final Property<Configuration> runtimeDependencies;

	...

	@Inject
	public VerifyDependenciesTask(ExtensionDescriptor config) {
		final JavaPluginExtension javaPluginExtension = getProject().getExtensions().getByType( JavaPluginExtension.class );
		final SourceSetContainer sourceSets = javaPluginExtension.getSourceSets();
		final SourceSet mainSourceSet = sourceSets.getByName( SourceSet.MAIN_SOURCE_SET_NAME );
		final ConfigurationContainer configurations = getProject().getConfigurations();

		runtimeDependencies = getProject().getObjects().property( Configuration.class );
		runtimeDependencies.set( configurations.getByName( mainSourceSet.getRuntimeClasspathConfigurationName() ) );
	}

	@Classpath
	public Provider<Configuration> getRuntimeDependencies() {
		return runtimeDependencies;
	}

	...
}

Am I using @Classpath incorrectly?

2

Does the task declare any outputs? If not, then it will never be up-to-date.

3

Thanks @Chris_Dore

That’s a bit disappointing. I have to create a completely useless output file just to get up-to-date checking to work. Well, useless outside of this Gradle requirement, anyway

4

No you don’t have to declare an output.
You just have to tell Gradle that it is ok to have no output and be up-to-date.
Just use outputs.upToDateWhen { true } and your task is able to be up-to-date without any actual outputs.

Btw. if you run with -i, Gradle tells you why a task is out of date like “no output defined”.

1 Like
5

And the task is still triggered when its inputs change? Wow, that would be perfect!

6

Exactly . . . . . . .

7

I was unaware the you could return true and get this behaviour. I was under the impression that returning true was effectively a NOP. Thanks for the info.