Revert behaviour to not prepend non-root top-level fields in JSON rendering.

This is a partial revert of #638, see discussion in #648.

Author: wenovus

demo/bgp/testdata/bgp-ietf.json

@@ -1,11 +1,11 @@
 {
-   "global": {
+   "openconfig-network-instance:global": {
       "config": {
          "as": 15169,
          "router-id": "192.0.2.42"
       }
    },
-   "neighbors": {
+   "openconfig-network-instance:neighbors": {
       "neighbor": [
          {
             "config": {

ygot/render.go

@@ -951,7 +951,7 @@ func (*RFC7951JSONConfig) IsMarshal7951Arg() {}
 // to JSON described by RFC7951. The supplied args control options corresponding
 // to the method by which JSON is marshalled.
 func ConstructIETFJSON(s ValidatedGoStruct, args *RFC7951JSONConfig) (map[string]interface{}, error) {
-	return structJSON(s, s.ΛBelongingModule(), jsonOutputConfig{
+	return structJSON(s, "", jsonOutputConfig{
 		jType:         RFC7951,
 		rfc7951Config: args,
 	})
@@ -1000,11 +1000,7 @@ func Marshal7951(d interface{}, args ...Marshal7951Arg) ([]byte, error) {
 			indent = string(v)
 		}
 	}
-	var parentMod string
-	if s, ok := d.(ValidatedGoStruct); ok {
-		parentMod = s.ΛBelongingModule()
-	}
-	j, err := jsonValue(reflect.ValueOf(d), parentMod, jsonOutputConfig{
+	j, err := jsonValue(reflect.ValueOf(d), "", jsonOutputConfig{
 		jType:         RFC7951,
 		rfc7951Config: rfcCfg,
 	})

ygot/render_test.go

@@ -2769,15 +2769,15 @@ func TestConstructJSON(t *testing.T) {
 		},
 		inAppendMod: true,
 		wantIETF: map[string]interface{}{
-			"f1": "foo",
-			"config": map[string]interface{}{
+			"f1mod:f1": "foo",
+			"f1mod:config": map[string]interface{}{
 				"f2mod:f6": "mat",
 			},
 			"f2mod:config": map[string]interface{}{
 				"f2":       "bar",
 				"f3mod:f7": "bat",
 			},
-			"f3": map[string]interface{}{
+			"f1mod:f3": map[string]interface{}{
 				"f42mod:config": map[string]interface{}{
 					"f4": "baz",
 				},
@@ -3552,7 +3552,7 @@ func TestEncodeTypedValue(t *testing.T) {
 		},
 		inEnc: gnmipb.Encoding_JSON_IETF,
 		want: &gnmipb.TypedValue{Value: &gnmipb.TypedValue_JsonIetfVal{[]byte(`{
-  "f1": "hello"
+  "f1mod:f1": "hello"
 }`)}},
 	}, {
 		name: "struct val - ietf json different module",
@@ -3858,7 +3858,7 @@ func TestMarshal7951(t *testing.T) {
 		inArgs: []Marshal7951Arg{
 			&RFC7951JSONConfig{AppendModuleName: true},
 		},
-		want: `{"f1":"hello"}`,
+		want: `{"f1mod:f1":"hello"}`,
 	}, {
 		desc: "complex children with module name prepend request",
 		in: &ietfRenderExample{
@@ -3873,22 +3873,22 @@ func TestMarshal7951(t *testing.T) {
 			JSONIndent("  "),
 		},
 		want: `{
-  "enum-list": [
+  "f1mod:enum-list": [
     {
       "config": {
         "key": "foo:VAL_ONE"
       },
       "key": "foo:VAL_ONE"
     }
   ],
-  "f2mod:config": {
-    "f2": "bar"
-  },
-  "mixed-list": [
+  "f1mod:mixed-list": [
     "foo:VAL_ONE",
     "test",
     42
-  ]
+  ],
+  "f2mod:config": {
+    "f2": "bar"
+  }
 }`,
 	}, {
 		desc: "complex children with PrependModuleNameIdentityref=true",
@@ -3935,22 +3935,22 @@ func TestMarshal7951(t *testing.T) {
 			JSONIndent("  "),
 		},
 		want: `{
-  "enum-list": [
+  "f1mod:enum-list": [
     {
       "config": {
         "key": "foo:VAL_ONE"
       },
       "key": "foo:VAL_ONE"
     }
   ],
-  "f2mod:config": {
-    "f2": "bar"
-  },
-  "mixed-list": [
+  "f1mod:mixed-list": [
     "foo:VAL_ONE",
     "test",
     42
-  ]
+  ],
+  "f2mod:config": {
+    "f2": "bar"
+  }
 }`,
 	}}