Receive only close channel.

[Skarlso]

Hello. I'm seeking some answers.

There is this code in wait.go:

// ContextForChannel provides a context that will be treated as cancelled
// when the provided parentCh is closed. The implementation returns
// context.Canceled for Err() if and only if the parentCh is closed.
func ContextForChannel(parentCh <-chan struct{}) context.Context {
	return channelContext{stopCh: parentCh}
}

var _ context.Context = channelContext{}

// channelContext will behave as if the context were cancelled when stopCh is
// closed.
type channelContext struct {
	stopCh <-chan struct{}
}

func (c channelContext) Done() <-chan struct{} { return c.stopCh }
func (c channelContext) Err() error {
	select {
	case <-c.stopCh:
		return context.Canceled
	default:
		return nil
	}
}

This will never work because the parent channel is declared as receive only channel.

You can't close a receive only channel as closing is a send operation. There are other places where the close channel is declared as receive only. What's the rational there?

[Skarlso]

Nevermind. The passed in channel is bidirectional and IT can be closed:

type namedChannelWrapper struct {
	name string
	once sync.Once
	ch   chan struct{}
}

func (e *namedChannelWrapper) Signal() {
	e.once.Do(func() {
		close(e.ch)
	})
}

func (e *namedChannelWrapper) Signaled() <-chan struct{} {
	return e.ch
}

func (e *namedChannelWrapper) Name() string {
	return e.name
}