projectsConfigured(":buildSrc", ":b")
            buildModelCreated()
            modelsCreated(":", ":a")
        }

        outputContains("Callback before root project 'root'")
        outputContains("Callback before project ':a'")
        outputContains("Callback before project ':b'")


        when:
        withIsolatedProjects()
        def model2 = runBuildAction(new FetchCustomModelForEachProject())

    }

    /**
     * Registers a callback to be called just before the service represented by this provider is stopped.
     * The callback runs even if the service wasn't created.
     * This provider is used as a callback argument.
     * <p>
     * The service will only be stopped after completing all registered callbacks.
     *
     * @param stopAction the callback
     */

// when the tags change.
type TagWatcher interface {
	Run(stopCh <-chan struct{})
	HasSynced() bool
	AddHandler(handler TagHandler)
	GetMyTags() sets.String
}

// TagHandler is a callback for when the tags revision change.
type TagHandler func(sets.String)

type tagWatcher struct {
	revision string
	handlers []TagHandler

	queue    controllers.Queue