fix: make findOwners handle custom types better

This change stops the controller from bubbling up an error when it
encounters a Kind that is has not registered in its scheme or an object
that it does not have access to. In these situations, the controller
will now stop climbing the ownership tree instead.

The new behaviour is desireable when an unsupported type (such as one
from a company's in-house operator) is marked as the controller of the
resource that controls the pods themselves.

Author: DWSR

components/migrations.go

@@ -30,6 +30,7 @@ import (
 	kerrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
 	ctrl "sigs.k8s.io/controller-runtime"
@@ -311,11 +312,19 @@ func (_ *migrationsComponent) findOwners(ctx *cu.Context, obj cu.Object) ([]cu.O
 		gvk := schema.FromAPIVersionAndKind(ref.APIVersion, ref.Kind)
 		ownerObj, err := ctx.Scheme.New(gvk)
 		if err != nil {
+			// Gracefully handle kinds that we haven't registered. Useful when a Rollout or Deployment is
+			// owned by someone's in-house operator
+			if runtime.IsNotRegisteredError(err) {
+				break
+			}
 			return nil, errors.Wrapf(err, "error finding object type for owner reference %v", ref)
 		}
 		err = ctx.Client.Get(ctx, types.NamespacedName{Name: ref.Name, Namespace: namespace}, ownerObj)
 		if err != nil {
-			// TODO IMPORTANT If this is a 403, don't bubble up the error. Probably a custom type we don't have access to, just pretend it's not there.
+			// Gracefully handle objects we don't have access to
+			if kerrors.IsForbidden(err) {
+				break
+			}
 			return nil, errors.Wrapf(err, "error finding object type for owner reference %v", ref)
 		}
 		obj = ownerObj.(cu.Object)