Fix unmarshaling of nested structs (#340)

Fixes #339

marshal.go

@@ -575,20 +575,22 @@ func (d *Decoder) valueFromTree(mtype reflect.Type, tval *Tree, mval1 *reflect.V
 				}
 
 				found := false
-				for _, key := range keysToTry {
-					exists := tval.Has(key)
-					if !exists {
-						continue
+				if tval != nil {
+					for _, key := range keysToTry {
+						exists := tval.Has(key)
+						if !exists {
+							continue
+						}
+						val := tval.Get(key)
+						fval := mval.Field(i)
+						mvalf, err := d.valueFromToml(mtypef.Type, val, &fval)
+						if err != nil {
+							return mval, formatError(err, tval.GetPosition(key))
+						}
+						mval.Field(i).Set(mvalf)
+						found = true
+						break
 					}
-					val := tval.Get(key)
-					fval := mval.Field(i)
-					mvalf, err := d.valueFromToml(mtypef.Type, val, &fval)
-					if err != nil {
-						return mval, formatError(err, tval.GetPosition(key))
-					}
-					mval.Field(i).Set(mvalf)
-					found = true
-					break
 				}
 
 				if !found && opts.defaultValue != "" {
@@ -626,7 +628,11 @@ func (d *Decoder) valueFromTree(mtype reflect.Type, tval *Tree, mval1 *reflect.V
 
 				// save the old behavior above and try to check structs
 				if !found && opts.defaultValue == "" && mtypef.Type.Kind() == reflect.Struct {
-					v, err := d.valueFromTree(mtypef.Type, tval, nil)
+					tmpTval := tval
+					if !mtypef.Anonymous {
+						tmpTval = nil
+					}
+					v, err := d.valueFromTree(mtypef.Type, tmpTval, nil)
 					if err != nil {
 						return v, err
 					}

marshal_test.go

@@ -2399,3 +2399,41 @@ func TestMarshalLocalTime(t *testing.T) {
 		})
 	}
 }
+
+// test case for issue #339
+func TestUnmarshalSameInnerField(t *testing.T) {
+	type InterStruct2 struct {
+		Test string
+		Name string
+		Age  int
+	}
+	type Inter2 struct {
+		Name         string
+		Age          int
+		InterStruct2 InterStruct2
+	}
+	type Server struct {
+		Name   string `toml:"name"`
+		Inter2 Inter2 `toml:"inter2"`
+	}
+
+	var server Server
+
+	if err := Unmarshal([]byte(`name = "123"
+[inter2]
+name = "inter2"
+age = 222`), &server); err == nil {
+		expected := Server{
+			Name: "123",
+			Inter2: Inter2{
+				Name: "inter2",
+				Age:  222,
+			},
+		}
+		if !reflect.DeepEqual(server, expected) {
+			t.Errorf("Bad unmarshal: expected %v, got %v", expected, server)
+		}
+	} else {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}