getOrElseGet() with provider as parameter for Property/Provider

[szpak]

Expected Behavior

There are cases where it is handy to return another provider if the current one is empty.

class PitestPluginExtension {
    final SetProperty<String> targetClasses
    final SetProperty<String> targetTests

//get targetClasses or if not use targetClasses 
= extension.targetTests.getOrElseGet(extension.targetClasses) //method name should be enhanced

Current Behavior

Without that it is needed to use ifPresent():

= project.providers.provider {
    if (extension.targetTests.isPresent()) {
        return extension.targetTests.get()
    } else {
        return task.targetClasses.getOrNull()
    }

Similar approach is used in java.util.Optional

[big-guy]

Do you have a little more detail on where/how = extension.targetTests.getOrElseGet(extension.targetClasses) is used?

[szpak]

Sure. If the targetTests parameter is not set by an user in the plugin configuration the value from targetClasses is taken - targetClasses is always set by the plugin logic and is a sensible default value. However, an user might want to narrow the scope of PIT execution to subset of tests. Sample usage in code and the original issue which brought me here.

[big-guy]

OK, in that case, could you just do:

extension.targetTests.convention(extension.targetClasses)

If targetTests is set explicitly, then that value is used.
If targetTests is not set, by convention, you use targetClasses.

[adammurdoch]

Have you looked at Provider.orElse(Provider), added in Gradle 5.6? It does what you're asking for in the description.

[szpak]

OK, in that case, could you just do:

extension.targetTests.convention(extension.targetClasses)

@big-guy I tried it before and with:

task.targetTests.convention(extension.targetClasses)
task.targetTests.set(extension.targetTests)

The second line overrides a default value even if extension.targetTests is a non-set provider. It's SetProperty<String> to maybe a default empty collection causes that? Is it an intended behavior?

---

Have you looked at Provider.orElse(Provider), added in Gradle 5.6? It does what you're asking for in the description.

@adammurdoch Yes, that's exactly what I needed, thanks. I've been looking for that, but maybe my IDE has an earlier Gradle version set, so I missed it.

[szpak]

Yes, that's exactly what I needed, thanks. I've been looking for that, but maybe my IDE has an earlier Gradle version set, so I missed it.

Ok, I missed it as it is named orElse() and return Provider not getOrElse() (which has just plain argument accepted). But, in general it's what I need.