Add indirect method

callback_query_preload.go

@@ -89,7 +89,7 @@ func (scope *Scope) handleHasOnePreload(field *Field, conditions []interface{})
 
 	// assign find results
 	var (
-		resultsValue       = reflect.Indirect(reflect.ValueOf(results))
+		resultsValue       = indirect(reflect.ValueOf(results))
 		indirectScopeValue = scope.IndirectValue()
 	)
 
@@ -98,7 +98,7 @@ func (scope *Scope) handleHasOnePreload(field *Field, conditions []interface{})
 		if indirectScopeValue.Kind() == reflect.Slice {
 			foreignValues := getValueFromFields(result, relation.ForeignFieldNames)
 			for j := 0; j < indirectScopeValue.Len(); j++ {
-				if indirectValue := reflect.Indirect(indirectScopeValue.Index(j)); equalAsString(getValueFromFields(indirectValue, relation.AssociationForeignFieldNames), foreignValues) {
+				if indirectValue := indirect(indirectScopeValue.Index(j)); equalAsString(getValueFromFields(indirectValue, relation.AssociationForeignFieldNames), foreignValues) {
 					indirectValue.FieldByName(field.Name).Set(result)
 					break
 				}
@@ -125,7 +125,7 @@ func (scope *Scope) handleHasManyPreload(field *Field, conditions []interface{})
 
 	// assign find results
 	var (
-		resultsValue       = reflect.Indirect(reflect.ValueOf(results))
+		resultsValue       = indirect(reflect.ValueOf(results))
 		indirectScopeValue = scope.IndirectValue()
 	)
 
@@ -134,7 +134,7 @@ func (scope *Scope) handleHasManyPreload(field *Field, conditions []interface{})
 			result := resultsValue.Index(i)
 			foreignValues := getValueFromFields(result, relation.ForeignFieldNames)
 			for j := 0; j < indirectScopeValue.Len(); j++ {
-				object := reflect.Indirect(indirectScopeValue.Index(j))
+				object := indirect(indirectScopeValue.Index(j))
 				if equalAsString(getValueFromFields(object, relation.AssociationForeignFieldNames), foreignValues) {
 					objectField := object.FieldByName(field.Name)
 					objectField.Set(reflect.Append(objectField, result))
@@ -163,7 +163,7 @@ func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{
 
 	// assign find results
 	var (
-		resultsValue       = reflect.Indirect(reflect.ValueOf(results))
+		resultsValue       = indirect(reflect.ValueOf(results))
 		indirectScopeValue = scope.IndirectValue()
 	)
 
@@ -172,7 +172,7 @@ func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{
 		if indirectScopeValue.Kind() == reflect.Slice {
 			value := getValueFromFields(result, relation.AssociationForeignFieldNames)
 			for j := 0; j < indirectScopeValue.Len(); j++ {
-				object := reflect.Indirect(indirectScopeValue.Index(j))
+				object := indirect(indirectScopeValue.Index(j))
 				if equalAsString(getValueFromFields(object, relation.ForeignFieldNames), value) {
 					object.FieldByName(field.Name).Set(result)
 				}
@@ -265,7 +265,7 @@ func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface
 
 	if indirectScopeValue.Kind() == reflect.Slice {
 		for j := 0; j < indirectScopeValue.Len(); j++ {
-			object := reflect.Indirect(indirectScopeValue.Index(j))
+			object := indirect(indirectScopeValue.Index(j))
 			fieldsSourceMap[toString(getValueFromFields(object, foreignFieldNames))] = object.FieldByName(field.Name)
 		}
 	} else if indirectScopeValue.IsValid() {

preload_test.go

@@ -611,6 +611,70 @@ func TestNestedPreload9(t *testing.T) {
 	}
 }
 
+type Level1A struct {
+	ID    uint
+	Value string
+}
+
+type Level1B struct {
+	ID      uint
+	Value   string
+	Level2s []*Level2
+}
+
+type Level2 struct {
+	ID        uint
+	Value     string
+	Level1AID sql.NullInt64
+	Level1A   *Level1A
+	Level1BID sql.NullInt64
+	Level1B   *Level1B
+}
+
+func TestNestedPreload10(t *testing.T) {
+	DB.DropTableIfExists(&Level2{})
+	DB.DropTableIfExists(&Level1B{})
+	DB.DropTableIfExists(&Level1A{})
+
+	if err := DB.AutoMigrate(&Level1A{}, &Level1B{}, &Level2{}).Error; err != nil {
+		t.Error(err)
+	}
+
+	level1A := &Level1A{Value: "foo"}
+	if err := DB.Save(&level1A).Error; err != nil {
+		t.Error(err)
+	}
+
+	want := []*Level1B{
+		&Level1B{
+			Value: "bar",
+			Level2s: []*Level2{
+				&Level2{
+					Value:   "qux",
+					Level1A: level1A,
+				},
+			},
+		},
+		&Level1B{
+			Value: "bar 2",
+		},
+	}
+	for _, level1B := range want {
+		if err := DB.Save(level1B).Error; err != nil {
+			t.Error(err)
+		}
+	}
+
+	var got []*Level1B
+	if err := DB.Preload("Level2s.Level1A").Find(&got).Error; err != nil {
+		t.Error(err)
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
+	}
+}
+
 func TestManyToManyPreloadWithMultiPrimaryKeys(t *testing.T) {
 	if dialect := os.Getenv("GORM_DIALECT"); dialect == "" || dialect == "sqlite" {
 		return

scope.go

@@ -16,7 +16,6 @@ type Scope struct {
 	Sql             string
 	SqlVars         []interface{}
 	db              *DB
-	indirectValue   *reflect.Value
 	instanceID      string
 	primaryKeyField *Field
 	skipLeft        bool
@@ -25,14 +24,7 @@ type Scope struct {
 }
 
 func (scope *Scope) IndirectValue() reflect.Value {
-	if scope.indirectValue == nil {
+	return indirect(reflect.ValueOf(scope.Value))
-		value := reflect.Indirect(reflect.ValueOf(scope.Value))
-		if value.Kind() == reflect.Ptr {
-			value = value.Elem()
-		}
-		scope.indirectValue = &value
-	}
-	return *scope.indirectValue
 }
 
 // New create a new Scope without search information

scope_utils.go

@@ -13,7 +13,7 @@ func (scope *Scope) getColumnAsArray(columns []string, values ...interface{}) (r
 		case reflect.Slice:
 			for i := 0; i < indirectValue.Len(); i++ {
 				var result []interface{}
-				var object = reflect.Indirect(indirectValue.Index(i))
+				var object = indirect(indirectValue.Index(i))
 				for _, column := range columns {
 					result = append(result, object.FieldByName(column).Interface())
 				}
@@ -44,7 +44,7 @@ func (scope *Scope) getColumnAsScope(column string) *Scope {
 			results := reflect.New(reflect.SliceOf(reflect.PtrTo(fieldType))).Elem()
 
 			for i := 0; i < indirectScopeValue.Len(); i++ {
-				result := reflect.Indirect(reflect.Indirect(indirectScopeValue.Index(i)).FieldByName(column))
+				result := indirect(indirect(indirectScopeValue.Index(i)).FieldByName(column))
 
 				if result.Kind() == reflect.Slice {
 					for j := 0; j < result.Len(); j++ {

utils.go

@@ -3,6 +3,7 @@ package gorm
 import (
 	"bytes"
 	"fmt"
+	"reflect"
 	"strings"
 	"sync"
 )
@@ -102,6 +103,13 @@ func Expr(expression string, args ...interface{}) *expr {
 	return &expr{expr: expression, args: args}
 }
 
+func indirect(reflectValue reflect.Value) reflect.Value {
+	for reflectValue.Kind() == reflect.Ptr {
+		reflectValue = reflectValue.Elem()
+	}
+	return reflectValue
+}
+
 func toQueryMarks(primaryValues [][]interface{}) string {
 	var results []string