Kotlin-dsl-samples: tasks.withType type parameter constraint is too restrictive

[ilya-g]

I can't configure all verification tasks using withType function in the following way:

tasks.withType<VerificationTask> {
    ignoreFailures = false
}

The VerificationTask is an interface that does not extend Task.

withType is declared as following:

fun <reified S : Any> DomainObjectCollection<in S>.withType(crossinline configuration: S.() -> Unit)

TaskContainer is a DomainObjectCollection<Task>. Therefore only Task and its subtypes can be used as S.

Your Environment

kotlin-dsl embedded in Gradle 4.2

[ilya-g]

I believe in S projection is not appropriate here, because the function doesn't put anything _into_ the collection.

[mkobit]

Another unfortunate thing is, I think in Groovy it just kind of works because Groovy throws out generic information.

tasks.withType(VerificationTask) {
   ignoreFailures = false
}

I haven't tried that, but I think it actually works.

Other types that also impacts are:

• https://docs.gradle.org/current/javadoc/org/gradle/process/JavaForkOptions.html
• https://docs.gradle.org/current/javadoc/org/gradle/process/ProcessForkOptions.html

[bamboo]

I agree. The constraint is inherited from the Gradle API so we first need to change it there:

• https://github.com/gradle/gradle/blob/b0032a8a355379e5868b22d660f8be5cf857168e/subprojects/core-api/src/main/java/org/gradle/api/DomainObjectCollection.java#L44

[eskatos]

Closing in favor of upstream https://github.com/gradle/gradle/issues/4050