Target set methods now check for types

internal/imported_tests/unmarshal_imported_test.go

@@ -421,26 +421,6 @@ func TestErrUnmarshal(t *testing.T) {
 	}
 }
 
-type emptyMarshalTestStruct struct {
-	Title      string                  `toml:"title"`
-	Bool       bool                    `toml:"bool"`
-	Int        int                     `toml:"int"`
-	String     string                  `toml:"string"`
-	StringList []string                `toml:"stringlist"`
-	Ptr        *basicMarshalTestStruct `toml:"ptr"`
-	Map        map[string]string       `toml:"map"`
-}
-
-var emptyTestData = emptyMarshalTestStruct{
-	Title:      "Placeholder",
-	Bool:       false,
-	Int:        0,
-	String:     "",
-	StringList: []string{},
-	Ptr:        nil,
-	Map:        map[string]string{},
-}
-
 var emptyTestToml = []byte(`bool = false
 int = 0
 string = ""
@@ -474,15 +454,30 @@ var emptyTestToml2 = []byte(`title = "Placeholder"
 `)
 
 func TestEmptytomlUnmarshal(t *testing.T) {
+	type emptyMarshalTestStruct struct {
+		Title      string                  `toml:"title"`
+		Bool       bool                    `toml:"bool"`
+		Int        int                     `toml:"int"`
+		String     string                  `toml:"string"`
+		StringList []string                `toml:"stringlist"`
+		Ptr        *basicMarshalTestStruct `toml:"ptr"`
+		Map        map[string]string       `toml:"map"`
+	}
+
+	emptyTestData := emptyMarshalTestStruct{
+		Title:      "Placeholder",
+		Bool:       false,
+		Int:        0,
+		String:     "",
+		StringList: []string{},
+		Ptr:        nil,
+		Map:        map[string]string{},
+	}
+
 	result := emptyMarshalTestStruct{}
 	err := toml.Unmarshal(emptyTestToml, &result)
-	expected := emptyTestData
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(result, expected) {
-		t.Errorf("Bad empty unmarshal: expected %v, got %v", expected, result)
-	}
+	require.NoError(t, err)
+	assert.Equal(t, emptyTestData, result)
 }
 
 func TestEmptyUnmarshalOmit(t *testing.T) {

internal/reflectbuild/reflectbuild.go

@@ -17,19 +17,32 @@ type structFieldGetters map[string]fieldGetter
 
 type target interface {
 	get() reflect.Value
-	set(value reflect.Value)
+	set(value reflect.Value) error
 
 	fmt.Stringer
 }
 
+func isAssignable(t reflect.Type, v reflect.Value) error {
+	if v.Type().AssignableTo(t) {
+		return nil
+	}
+	return fmt.Errorf("cannot assign '%s' ('%s') to a '%s'", v, v.Type(), t)
+}
+
 type valueTarget reflect.Value
 
 func (v valueTarget) get() reflect.Value {
 	return reflect.Value(v)
 }
 
-func (v valueTarget) set(value reflect.Value) {
+func (v valueTarget) set(value reflect.Value) error {
+	rv := reflect.Value(v)
+	err := isAssignable(rv.Type(), value)
+	if err != nil {
+		return err
+	}
 	reflect.Value(v).Set(value)
+	return nil
 }
 
 func (v valueTarget) String() string {
@@ -45,8 +58,13 @@ func (v mapTarget) get() reflect.Value {
 	return v.m.MapIndex(v.index)
 }
 
-func (v mapTarget) set(value reflect.Value) {
+func (v mapTarget) set(value reflect.Value) error {
+	err := isAssignable(v.m.Type().Elem(), value)
+	if err != nil {
+		return err
+	}
 	v.m.SetMapIndex(v.index, value)
+	return nil
 }
 
 func (v mapTarget) String() string {
@@ -413,23 +431,11 @@ func (b *Builder) SetString(s string) error {
 	t := b.top()
 	v := t.get()
 
-	if !v.IsValid() {
-		fmt.Println("============ INVALID ===========")
-		fmt.Println(b.Dump())
-		fmt.Println("==================== ===========")
-	}
-
 	if v.Kind() == reflect.Ptr {
 		v.Set(reflect.ValueOf(&s))
-	} else {
-		err := checkKind(v.Type(), reflect.String)
-		if err != nil {
-			return err
-		}
-
-		v.SetString(s)
+		return nil
 	}
-	return nil
+	return t.set(reflect.ValueOf(s))
 }
 
 // Set the value at the cursor to the given boolean.
@@ -481,8 +487,7 @@ func (b *Builder) SetInt(n int64) error {
 
 func (b *Builder) Set(v reflect.Value) error {
 	t := b.top()
-	t.set(v)
-	return nil
+	return t.set(v)
 }
 
 func checkKindInt(rt reflect.Type) error {