Available methods in gradle closure

Question

How do we know what available methods are in Gradle Closures? E.g.:

task greeting {
    dependsOn greeting0

    doLast {
        println("hi")
    }
}

In the above closure passed into task greeting, where do the Gradle specific dependsOn & doLast come from?

Both dependsOn and doLast are Task methods. However, if we take a look at the Project doc, the closure is only a simple Groovy Closure.

Answer 1

As an example, here's a Groovy DSL script which shows what's going on (I hope)

class Example {

    def missingMethod(String name, args) {
        println name
    }
    
    static run(Closure cl) {
        def project = new Project()
        cl.delegate = project
        cl.resolveStrategy = Closure.DELEGATE_FIRST
        cl.call()
    }
}

class Project {

    def task(taskDefinition) {
        def task = new Task()
        taskDefinition[0].delegate = task
        taskDefinition[0].resolveStrategy = Closure.DELEGATE_FIRST
        taskDefinition[0].call()
    }

    def and(String what) {
        println "Project $what"
    }
    
    def methodMissing(String name, args) {
        args
    }
}

class Task {

    def say(String what) {
        println "Task $what"
    }
}

// So now we can "run" a script
Example.run {

    task woo {
        say "hello" // From task
        and "world" // From project
    }
}

This prints

Task hello
Project world