runner: reset RESTMapper after CRD change

As otherwise with a persistent discovery client and/or REST mapper
configuration, newly installed CRDs will not be recognized and cause a
`resource mapping not found for name` error.

Signed-off-by: Hidde Beydals <hidde@hhh.computer>

internal/runner/runner.go

@@ -346,13 +346,23 @@ func (r *Runner) applyCRDs(policy v2.CRDsPolicy, chart *chart.Chart, visitorFunc
 		}
 		r.config.Log("Clearing discovery cache")
 		discoveryClient.Invalidate()
+
+		// Clear the RESTMapper cache, since it will not have the new CRDs.
+		if m, err := r.config.RESTClientGetter.ToRESTMapper(); err == nil {
+			if rm, ok := m.(meta.ResettableRESTMapper); ok {
+				r.config.Log("Clearing RESTMapper cache")
+				rm.Reset()
+			}
+		}
+
 		// Give time for the CRD to be recognized.
 		if err := r.config.KubeClient.Wait(totalItems, 60*time.Second); err != nil {
 			r.config.Log("Error waiting for items: %s", err)
 			return err
 		}
+
 		// Make sure to force a rebuild of the cache.
-		discoveryClient.ServerGroups()
+		_, _ = discoveryClient.ServerGroups()
 	}
 	return nil
 }