gateway-api: Missing serviceName behavior

I had another question on how we should handle errors (sorry for all the spam, but implementing is causing me to think about all these edge cases).

If I have an HTTPRoute like the following example, and one of the forwardTos are invalid (say the service is missing from the cluster). The docs say I should raise a ResolvedRefs condition and the route must be dropped.

My question is should the entire route be dropped or just that Match? If I had multiple matches for other paths, I’d ideally want to keep those serving traffic, but looking to be consistent since setting Admitted: false for a partial route also doesn’t make sense.

The Implementation Guide also says we should strive to serve traffic. I did have a quick conversation on Slack with @hbagdi regarding this (https://kubernetes.slack.com/archives/CR0H13KGA/p1612459180030400), so wanted to see what others thought on how to handle.

If the referent cannot be found, the route must be dropped from the Gateway. The controller should raise the “ResolvedRefs” condition on the Gateway with the “DegradedRoutes” reason. The gateway status for this route should be updated with a condition that describes the error more specifically.

Example:

kind: HTTPRoute
apiVersion: networking.x-k8s.io/v1alpha1
metadata:
  name: http-filter-1
  namespace: projectcontour-roots 
  labels:
    type: http
spec:
  gateways:
    allow: All
  hostnames:
    - local.projectcontour.io
  rules:
  - matches:
      - path:
          type: Prefix
          value: /
      forwardTo:
      - serviceName: validservice    # <--- valid serviceName/match
        port: 80
    - matches:
      - path:
          type: Prefix
          value: /blog
      forwardTo:
      - serviceName: boohiss    # <--- invalid serviceName
        port: 80