Merge pull request kubernetes#104209 from liggitt/automated-cherry-pi…

…ck-of-#104182-upstream-release-1.20

Automated cherry pick of kubernetes#104182: Avoid spurious calls to update/delete validation

staging/src/k8s.io/apiserver/pkg/storage/etcd3/store.go

@@ -301,12 +301,22 @@ func (s *store) GuaranteedUpdate(
 			}
 
 			// It's possible we were working with stale data
+			// Remember the revision of the potentially stale data and the resulting update error
+			cachedRev := origState.rev
+			cachedUpdateErr := err
+
 			// Actually fetch
 			origState, err = getCurrentState()
 			if err != nil {
 				return err
 			}
 			mustCheckData = false
+
+			// it turns out our cached data was not stale, return the error
+			if cachedRev == origState.rev {
+				return cachedUpdateErr
+			}
+
 			// Retry
 			continue
 		}

staging/src/k8s.io/apiserver/pkg/storage/etcd3/store_test.go

@@ -817,6 +817,35 @@ func TestGuaranteedUpdateWithSuggestionAndConflict(t *testing.T) {
 	if updatedPod2.Name != "foo-3" {
 		t.Errorf("unexpected pod name: %q", updatedPod2.Name)
 	}
+
+	// Third, update using a current version as the suggestion.
+	// Return an error and make sure that SimpleUpdate is NOT called a second time,
+	// since the live lookup shows the suggestion was already up to date.
+	attempts := 0
+	updatedPod3 := &example.Pod{}
+	err = store.GuaranteedUpdate(ctx, key, updatedPod3, false, nil,
+		storage.SimpleUpdate(func(obj runtime.Object) (runtime.Object, error) {
+			pod := obj.(*example.Pod)
+			if pod.Name != updatedPod2.Name || pod.ResourceVersion != updatedPod2.ResourceVersion {
+				t.Errorf(
+					"unexpected live object (name=%s, rv=%s), expected name=%s, rv=%s",
+					pod.Name,
+					pod.ResourceVersion,
+					updatedPod2.Name,
+					updatedPod2.ResourceVersion,
+				)
+			}
+			attempts++
+			return nil, fmt.Errorf("validation or admission error")
+		}),
+		updatedPod2,
+	)
+	if err == nil {
+		t.Fatalf("expected error, got none")
+	}
+	if attempts != 1 {
+		t.Errorf("expected 1 attempt, got %d", attempts)
+	}
 }
 
 func TestTransformationFailure(t *testing.T) {