Merge pull request #55936 from shiywang/json_test_enhance

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Some test enhance, comments enhance and duplicate code reduce

while I was learning the codebase, found some place could be enhance, not confident about the comments of `Decode`  I changed isn't right.

/assign @sttts   PTAL, thanks

```release-note
NONE
```

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/json/json.go

@@ -98,11 +98,29 @@ func init() {
 	jsoniter.RegisterTypeDecoderFunc("interface {}", decodeNumberAsInt64IfPossible)
 }
 
+// gvkWithDefaults returns group kind and version defaulting from provided default
+func gvkWithDefaults(actual, defaultGVK schema.GroupVersionKind) schema.GroupVersionKind {
+	if len(actual.Kind) == 0 {
+		actual.Kind = defaultGVK.Kind
+	}
+	if len(actual.Version) == 0 && len(actual.Group) == 0 {
+		actual.Group = defaultGVK.Group
+		actual.Version = defaultGVK.Version
+	}
+	if len(actual.Version) == 0 && actual.Group == defaultGVK.Group {
+		actual.Version = defaultGVK.Version
+	}
+	return actual
+}
+
 // Decode attempts to convert the provided data into YAML or JSON, extract the stored schema kind, apply the provided default gvk, and then
-// load that data into an object matching the desired schema kind or the provided into. If into is *runtime.Unknown, the raw data will be
+// load that data into an object matching the desired schema kind or the provided into.
-// extracted and no decoding will be performed. If into is not registered with the typer, then the object will be straight decoded using
+// If into is *runtime.Unknown, the raw data will be extracted and no decoding will be performed.
-// normal JSON/YAML unmarshalling. If into is provided and the original data is not fully qualified with kind/version/group, the type of
+// If into is not registered with the typer, then the object will be straight decoded using normal JSON/YAML unmarshalling.
-// the into will be used to alter the returned gvk. On success or most errors, the method will return the calculated schema kind.
+// If into is provided and the original data is not fully qualified with kind/version/group, the type of the into will be used to alter the returned gvk.
+// If into is nil or data's gvk different from into's gvk, it will generate a new Object with ObjectCreater.New(gvk)
+// On success or most errors, the method will return the calculated schema kind.
+// The gvk calculate priority will be originalData > default gvk > into
 func (s *Serializer) Decode(originalData []byte, gvk *schema.GroupVersionKind, into runtime.Object) (runtime.Object, *schema.GroupVersionKind, error) {
 	if versioned, ok := into.(*runtime.VersionedObjects); ok {
 		into = versioned.Last()
@@ -129,17 +147,7 @@ func (s *Serializer) Decode(originalData []byte, gvk *schema.GroupVersionKind, i
 	}
 
 	if gvk != nil {
-		// apply kind and version defaulting from provided default
+		*actual = gvkWithDefaults(*actual, *gvk)
-		if len(actual.Kind) == 0 {
-			actual.Kind = gvk.Kind
-		}
-		if len(actual.Version) == 0 && len(actual.Group) == 0 {
-			actual.Group = gvk.Group
-			actual.Version = gvk.Version
-		}
-		if len(actual.Version) == 0 && actual.Group == gvk.Group {
-			actual.Version = gvk.Version
-		}
 	}
 
 	if unk, ok := into.(*runtime.Unknown); ok && unk != nil {
@@ -161,17 +169,7 @@ func (s *Serializer) Decode(originalData []byte, gvk *schema.GroupVersionKind, i
 		case err != nil:
 			return nil, actual, err
 		default:
-			typed := types[0]
+			*actual = gvkWithDefaults(*actual, types[0])
-			if len(actual.Kind) == 0 {
-				actual.Kind = typed.Kind
-			}
-			if len(actual.Version) == 0 && len(actual.Group) == 0 {
-				actual.Group = typed.Group
-				actual.Version = typed.Version
-			}
-			if len(actual.Version) == 0 && actual.Group == typed.Group {
-				actual.Version = typed.Version
-			}
 		}
 	}
 

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/json/json_test.go

@@ -94,6 +94,32 @@ func TestDecode(t *testing.T) {
 			expectedObject: &testDecodable{},
 			expectedGVK:    &schema.GroupVersionKind{Kind: "Test", Group: "other", Version: "blah"},
 		},
+		// group version, kind is defaulted
+		{
+			data:           []byte(`{"apiVersion":"other1/blah1"}`),
+			defaultGVK:     &schema.GroupVersionKind{Kind: "Test", Group: "other", Version: "blah"},
+			creater:        &mockCreater{obj: &testDecodable{}},
+			expectedObject: &testDecodable{},
+			expectedGVK:    &schema.GroupVersionKind{Kind: "Test", Group: "other1", Version: "blah1"},
+		},
+		// gvk all provided then not defaulted at all
+		{
+			data:           []byte(`{"kind":"Test","apiVersion":"other/blah"}`),
+			defaultGVK:     &schema.GroupVersionKind{Kind: "Test1", Group: "other1", Version: "blah1"},
+			creater:        &mockCreater{obj: &testDecodable{}},
+			expectedObject: &testDecodable{},
+			expectedGVK:    &schema.GroupVersionKind{Kind: "Test", Group: "other", Version: "blah"},
+		},
+		//gvk defaulting if kind not provided in data and defaultGVK use into's kind
+		{
+			data:           []byte(`{"apiVersion":"b1/c1"}`),
+			into:           &testDecodable{gvk: schema.GroupVersionKind{Kind: "a3", Group: "b1", Version: "c1"}},
+			typer:          &mockTyper{gvk: &schema.GroupVersionKind{Kind: "a3", Group: "b1", Version: "c1"}},
+			defaultGVK:     nil,
+			creater:        &mockCreater{obj: &testDecodable{}},
+			expectedObject: &testDecodable{gvk: schema.GroupVersionKind{Kind: "a3", Group: "b1", Version: "c1"}},
+			expectedGVK:    &schema.GroupVersionKind{Kind: "a3", Group: "b1", Version: "c1"},
+		},
 
 		// accept runtime.Unknown as into and bypass creator
 		{