Merge pull request #85 from zerosnake0/issue84

fix embedded struct copy

copier.go

@@ -194,27 +194,24 @@ func copier(toValue interface{}, fromValue interface{}, opt Option) (err error)
 					// process for nested anonymous field
 					destFieldNotSet := false
 					if f, ok := dest.Type().FieldByName(name); ok {
-						for idx, x := range f.Index {
-							if x >= dest.NumField() {
-								continue
-							}
+						for idx := range f.Index {
+							destField := dest.FieldByIndex(f.Index[:idx+1])
 
-							destFieldKind := dest.Field(x).Kind()
-							if destFieldKind != reflect.Ptr {
+							if destField.Kind() != reflect.Ptr {
 								continue
 							}
 
-							if !dest.Field(x).IsNil() {
+							if !destField.IsNil() {
 								continue
 							}
-
-							if !dest.Field(x).CanSet() {
+							if !destField.CanSet() {
 								destFieldNotSet = true
 								break
 							}
 
-							newValue := reflect.New(dest.FieldByIndex(f.Index[0 : idx+1]).Type().Elem())
-							dest.Field(x).Set(newValue)
+							// destField is a nil pointer that can be set
+							newValue := reflect.New(destField.Type().Elem())
+							destField.Set(newValue)
 						}
 					}
 

copier_issue84_test.go

@@ -0,0 +1,89 @@
+package copier_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/jinzhu/copier"
+)
+
+type Embedded struct {
+	Field1 string
+	Field2 string
+}
+
+type Embedder struct {
+	Embedded
+	PtrField *string
+}
+
+type Timestamps struct {
+	CreatedAt time.Time `json:"created_at"`
+	UpdatedAt time.Time `json:"updated_at"`
+}
+
+type NotWork struct {
+	ID      string  `json:"id"`
+	UserID  *string `json:"user_id"`
+	Name    string  `json:"name"`
+	Website *string `json:"website"`
+	Timestamps
+}
+
+type Work struct {
+	ID      string  `json:"id"`
+	Name    string  `json:"name"`
+	UserID  *string `json:"user_id"`
+	Website *string `json:"website"`
+	Timestamps
+}
+
+func TestIssue84(t *testing.T) {
+	t.Run("test1", func(t *testing.T) {
+		var embedder Embedder
+		embedded := Embedded{
+			Field1: "1",
+			Field2: "2",
+		}
+		err := copier.Copy(&embedder, &embedded)
+		if err != nil {
+			t.Errorf("unable to copy: %s", err)
+		}
+		if embedder.Field1 != embedded.Field1 {
+			t.Errorf("field1 value is %s instead of %s", embedder.Field1, embedded.Field1)
+		}
+		if embedder.Field2 != embedded.Field2 {
+			t.Errorf("field2 value is %s instead of %s", embedder.Field2, embedded.Field2)
+		}
+	})
+	t.Run("from issue", func(t *testing.T) {
+		notWorkObj := NotWork{
+			ID:      "123",
+			Name:    "name",
+			Website: nil,
+			UserID:  nil,
+			Timestamps: Timestamps{
+				UpdatedAt: time.Now(),
+			},
+		}
+		workObj := Work{
+			ID:      "123",
+			Name:    "name",
+			Website: nil,
+			UserID:  nil,
+			Timestamps: Timestamps{
+				UpdatedAt: time.Now(),
+			},
+		}
+
+		destObj1 := Work{}
+		destObj2 := NotWork{}
+
+		copier.CopyWithOption(&destObj1, &workObj, copier.Option{IgnoreEmpty: true, DeepCopy: false})
+		fmt.Println(destObj1)
+
+		copier.CopyWithOption(&destObj2, &notWorkObj, copier.Option{IgnoreEmpty: true, DeepCopy: false})
+		fmt.Println(destObj2)
+	})
+}