This moves a relatively pristine copy of EnsureTypeMeta into knative/pkg. (#157)

controller/helper.go

@@ -0,0 +1,51 @@
+/*
+Copyright 2018 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controller
+
+import (
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+type Callback func(interface{})
+
+func EnsureTypeMeta(f Callback, gvk schema.GroupVersionKind) Callback {
+	apiVersion, kind := gvk.ToAPIVersionAndKind()
+
+	return func(untyped interface{}) {
+		// TODO(mattmoor): Handle deletion.
+		typed, ok := untyped.(runtime.Object)
+		if !ok {
+			return
+		}
+		// We need to populated TypeMeta, but cannot trample the
+		// informer's copy.
+		// TODO(mattmoor): Avoid the copy if TypeMeta is set.
+		copy := typed.DeepCopyObject()
+
+		accessor, err := meta.TypeAccessor(copy)
+		if err != nil {
+			return
+		}
+		accessor.SetAPIVersion(apiVersion)
+		accessor.SetKind(kind)
+
+		// Pass in the mutated copy (accessor is not just a type cast)
+		f(copy)
+	}
+}

controller/helper_test.go

@@ -0,0 +1,87 @@
+/*
+Copyright 2018 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controller
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+
+	. "github.com/knative/pkg/testing"
+)
+
+func TestEnsureTypeMeta(t *testing.T) {
+	gvk := schema.GroupVersionKind{
+		Group:   "foo.bar.com",
+		Version: "v23",
+		Kind:    "Magic",
+	}
+	apiVersion, kind := gvk.ToAPIVersionAndKind()
+
+	tests := []struct {
+		name string
+		obj  interface{}
+		want runtime.Object
+	}{{
+		name: "not a runtime.Object",
+		obj:  struct{}{},
+	}, {
+		name: "called with type meta",
+		obj: &Resource{
+			ObjectMeta: metav1.ObjectMeta{
+				Namespace: "default",
+				Name:      "thing",
+			},
+		},
+		want: &Resource{
+			TypeMeta: metav1.TypeMeta{
+				APIVersion: apiVersion,
+				Kind:       kind,
+			},
+			ObjectMeta: metav1.ObjectMeta{
+				Namespace: "default",
+				Name:      "thing",
+			},
+		},
+	}}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			var cb Callback
+			if test.want != nil {
+				cb = func(got interface{}) {
+					if diff := cmp.Diff(got, test.want); diff != "" {
+						t.Errorf("EnsureTypeMeta = %s", diff)
+					}
+				}
+			} else {
+				cb = func(got interface{}) {
+					t.Errorf("Wanted no call, got %#v", got)
+				}
+			}
+
+			ncb := EnsureTypeMeta(cb, gvk)
+
+			// This should either invoke the callback or not, the
+			// rest of the test is in the configured callback.
+			ncb(test.obj)
+		})
+	}
+}