Please answer these questions before submitting your issue.

What version of gRPC are you using?

1.20.0

What did you expect to see?

I've implemented a custom NameResolver to resolve addresses in Consul (DNS or HTTP). We're pairing this name resolver with the RoundRobinLoadBalancer to provide simple client-side load balancing.

While integration testing, I found that if we return an empty list of addresses in the name resolver, no refresh is ever triggered on the NameResolver (leading to a permanent error of UNAVAILABLE for all calls). If I change the NameResolver implementation to call Listener.onError() instead when no addresses are found, refresh() will eventually be triggered and the problem can resolve itself.

When writing the name resolver, I believe I may have gotten tripped up on this comment (which makes it sound like onAddresses() with an empty list is equivalent to onError()):

For reference, the DNS name resolver doesn't pass an empty list of addresses:

I'm not sure if this is expected behavior and I know this is an experimental API, but wanted to report in case this wasn't the desired behavior.