Automatic merge from submit-queue
Return 'too old' errors from watch cache via watch stream
Fixes#25151
This PR updates the API server to produce the same results when a watch is attempted with a resourceVersion that is too old, regardless of whether the etcd watch cache is enabled. The expected result is a `200` http status, with a single watch event of type `ERROR`. Previously, the watch cache would deliver a `410` http response.
This is the uncached watch impl:
```
// Implements storage.Interface.
func (h *etcdHelper) WatchList(ctx context.Context, key string, resourceVersion string, filter storage.FilterFunc) (watch.Interface, error) {
if ctx == nil {
glog.Errorf("Context is nil")
}
watchRV, err := storage.ParseWatchResourceVersion(resourceVersion)
if err != nil {
return nil, err
}
key = h.prefixEtcdKey(key)
w := newEtcdWatcher(true, h.quorum, exceptKey(key), filter, h.codec, h.versioner, nil, h)
go w.etcdWatch(ctx, h.etcdKeysAPI, key, watchRV)
return w, nil
}
```
once the resourceVersion parses, there is no path that returns a direct error, so all errors would have to be returned as an `ERROR` event via the ResultChan().
aa8fddb7d9