On the Gradle user guide, there is a section about hidden tasks: https://docs.gradle.org/current/userguide/more_about_tasks.html#sec:hidden_tasks

Gradle doesn’t support marking a task as private.

However, tasks will only show up when running

:tasks

if

task.group

is set or no other task depends on it.

So for the code example:

tasks.register("helloTask") {
    println("Hello")
}

I understand this task doesn’t show up in

./gradlew tasks

because no group has been assigned to it. However since the docs say “or no other task depends on it”, since there are no tasks depending on this task then shouldn’t it still show in

./gradlew tasks

?

Sounds like it. You should open an issue. Either the implementation is broken, or the docs are wrong