refactor(*): make "not found" error message user-friendly

Signed-off-by: Pavel Eremeev <selslack@users.noreply.github.com>

pkg/kube/client.go

@@ -333,9 +333,15 @@ func (c *Client) Update(namespace string, originalReader, targetReader io.Reader
 		}
 
 		originalInfo := original.Get(info)
+
+		// Resource exists in the current cluster state, but not in the current helm configuration
+		// See: https://github.com/helm/helm/issues/1193 for more info
 		if originalInfo == nil {
-			kind := info.Mapping.GroupVersionKind.Kind
-			return fmt.Errorf("no %s with the name %q found", kind, info.Name)
+			return fmt.Errorf(
+				"%s %q is not managed by Helm; delete the resource from the current cluster state to let Helm manage it",
+				info.Mapping.GroupVersionKind.Kind,
+				info.Name,
+			)
 		}
 
 		if err := updateResource(c, info, originalInfo.Object, force, recreate); err != nil {

pkg/kube/client_test.go

@@ -224,6 +224,43 @@ func TestUpdate(t *testing.T) {
 	}
 }
 
+func TestUpdateNonManagedResourceError(t *testing.T) {
+	actual := newPodList("starfish")
+	current := newPodList()
+	target := newPodList("starfish")
+
+	tf := cmdtesting.NewTestFactory()
+	defer tf.Cleanup()
+
+	tf.UnstructuredClient = &fake.RESTClient{
+		NegotiatedSerializer: unstructuredSerializer,
+		Client: fake.CreateHTTPClient(func(req *http.Request) (*http.Response, error) {
+			p, m := req.URL.Path, req.Method
+			t.Logf("got request %s %s", p, m)
+			switch {
+			case p == "/namespaces/default/pods/starfish" && m == "GET":
+				return newResponse(200, &actual.Items[0])
+			default:
+				t.Fatalf("unexpected request: %s %s", req.Method, req.URL.Path)
+				return nil, nil
+			}
+		}),
+	}
+
+	c := &Client{
+		Factory: tf,
+		Log:     nopLogger,
+	}
+
+	if err := c.Update(v1.NamespaceDefault, objBody(&current), objBody(&target), false, false, 0, false); err != nil {
+		if err.Error() != "Pod \"starfish\" is not managed by Helm; delete the resource from the current cluster state to let Helm manage it" {
+			t.Fatal(err)
+		}
+	} else {
+		t.Fatalf("error expected")
+	}
+}
+
 func TestBuild(t *testing.T) {
 	tests := []struct {
 		name      string