fix issue #1946 (#2194)

* fix issue #1946

* fix issue #1946

util/gconv/gconv_struct.go

@@ -534,14 +534,20 @@ func bindVarToReflectValue(structFieldValue reflect.Value, value interface{}, ma
 		structFieldValue.Set(reflectArray)
 
 	case reflect.Ptr:
-		item := reflect.New(structFieldValue.Type().Elem())
-		if err, ok = bindVarToReflectValueWithInterfaceCheck(item, value); ok {
-			structFieldValue.Set(item)
-			return err
-		}
-		elem := item.Elem()
-		if err = bindVarToReflectValue(elem, value, mapping); err == nil {
-			structFieldValue.Set(elem.Addr())
+		if structFieldValue.IsNil() || structFieldValue.IsZero() {
+			// Nil or empty pointer, it creates a new one.
+			item := reflect.New(structFieldValue.Type().Elem())
+			if err, ok = bindVarToReflectValueWithInterfaceCheck(item, value); ok {
+				structFieldValue.Set(item)
+				return err
+			}
+			elem := item.Elem()
+			if err = bindVarToReflectValue(elem, value, mapping); err == nil {
+				structFieldValue.Set(elem.Addr())
+			}
+		} else {
+			// Not empty pointer, it assigns values to it.
+			return bindVarToReflectValue(structFieldValue.Elem(), value, mapping)
 		}
 
 	// It mainly and specially handles the interface of nil value.

util/gconv/gconv_z_unit_all_test.go

@@ -11,6 +11,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/gogf/gf/v2/container/gtype"
 	"github.com/gogf/gf/v2/frame/g"
 	"github.com/gogf/gf/v2/os/gtime"
 	"github.com/gogf/gf/v2/test/gtest"
@@ -1480,3 +1481,76 @@ func Test_Struct_Time_All(t *testing.T) {
 		t.Assert(user.CreateTime.Time.UTC().String(), now.UTC().String())
 	})
 }
+
+func Test_Issue1946(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		type B struct {
+			init *gtype.Bool
+			Name string
+		}
+		type A struct {
+			B *B
+		}
+		a := &A{
+			B: &B{
+				init: gtype.NewBool(true),
+			},
+		}
+		err := gconv.Struct(g.Map{
+			"B": g.Map{
+				"Name": "init",
+			},
+		}, a)
+		t.AssertNil(err)
+		t.Assert(a.B.Name, "init")
+		t.Assert(a.B.init.Val(), true)
+	})
+	// It cannot change private attribute.
+	gtest.C(t, func(t *gtest.T) {
+		type B struct {
+			init *gtype.Bool
+			Name string
+		}
+		type A struct {
+			B *B
+		}
+		a := &A{
+			B: &B{
+				init: gtype.NewBool(true),
+			},
+		}
+		err := gconv.Struct(g.Map{
+			"B": g.Map{
+				"init": 0,
+				"Name": "init",
+			},
+		}, a)
+		t.AssertNil(err)
+		t.Assert(a.B.Name, "init")
+		t.Assert(a.B.init.Val(), true)
+	})
+	// It can change public attribute.
+	gtest.C(t, func(t *gtest.T) {
+		type B struct {
+			Init *gtype.Bool
+			Name string
+		}
+		type A struct {
+			B *B
+		}
+		a := &A{
+			B: &B{
+				Init: gtype.NewBool(),
+			},
+		}
+		err := gconv.Struct(g.Map{
+			"B": g.Map{
+				"Init": 1,
+				"Name": "init",
+			},
+		}, a)
+		t.AssertNil(err)
+		t.Assert(a.B.Name, "init")
+		t.Assert(a.B.Init.Val(), true)
+	})
+}