Merge Go 1.10+ files

yaml.go

@@ -417,3 +417,10 @@ func jsonToYAMLValue(j interface{}) interface{} {
 	}
 	return j
 }
+
+// DisallowUnknownFields configures the JSON decoder to error out if unknown
+// fields come along, instead of dropping them by default.
+func DisallowUnknownFields(d *json.Decoder) *json.Decoder {
+	d.DisallowUnknownFields()
+	return d
+}

yaml_test.go

@@ -949,3 +949,41 @@ spec:
 		t.Fatalf("expected\n%s\ngot\n%s", string(v2output), v3output)
 	}
 }
+
+func TestUnmarshalWithTags(t *testing.T) {
+	type WithTaggedField struct {
+		Field string `json:"field"`
+	}
+
+	t.Run("Known tagged field", func(t *testing.T) {
+		y := []byte(`field: "hello"`)
+		v := WithTaggedField{}
+		if err := Unmarshal(y, &v, DisallowUnknownFields); err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		if v.Field != "hello" {
+			t.Errorf("v.Field=%v, want 'hello'", v.Field)
+		}
+
+	})
+	t.Run("With unknown tagged field", func(t *testing.T) {
+		y := []byte(`unknown: "hello"`)
+		v := WithTaggedField{}
+		err := Unmarshal(y, &v, DisallowUnknownFields)
+		if err == nil {
+			t.Errorf("want error because of unknown field, got <nil>: v=%#v", v)
+		}
+	})
+
+}
+
+func exampleUnknown() {
+	type WithTaggedField struct {
+		Field string `json:"field"`
+	}
+	y := []byte(`unknown: "hello"`)
+	v := WithTaggedField{}
+	fmt.Printf("%v\n", Unmarshal(y, &v, DisallowUnknownFields))
+	// Ouptut:
+	// unmarshaling JSON: while decoding JSON: json: unknown field "unknown"
+}