From aac52fdcf8c0cef3b4bc4139a7a7ef72319ca6d1 Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Wed, 11 Feb 2015 17:58:19 +0800
Subject: [PATCH] Fix Preload with slice of pointer

---
 preload.go      | 16 ++++++++++------
 preload_test.go |  8 ++++++++
 scope.go        |  7 ++++++-
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/preload.go b/preload.go
index 1e6c26b3..4e48db53 100644
--- a/preload.go
+++ b/preload.go
@@ -8,7 +8,7 @@ import (
 )
 
 func getFieldValue(value reflect.Value, field string) interface{} {
-	result := value.FieldByName(field).Interface()
+	result := reflect.Indirect(value).FieldByName(field).Interface()
 	if r, ok := result.(driver.Valuer); ok {
 		result, _ = r.Value()
 	}
@@ -25,7 +25,11 @@ func Preload(scope *Scope) {
 	var isSlice bool
 	if scope.IndirectValue().Kind() == reflect.Slice {
 		isSlice = true
-		elem := reflect.New(scope.IndirectValue().Type().Elem()).Elem()
+		typ := scope.IndirectValue().Type().Elem()
+		if typ.Kind() == reflect.Ptr {
+			typ = typ.Elem()
+		}
+		elem := reflect.New(typ).Elem()
 		fields = scope.New(elem.Addr().Interface()).Fields()
 	} else {
 		fields = scope.Fields()
@@ -53,7 +57,7 @@ func Preload(scope *Scope) {
 								objects := scope.IndirectValue()
 								for j := 0; j < objects.Len(); j++ {
 									if equalAsString(getFieldValue(objects.Index(j), primaryName), value) {
-										objects.Index(j).FieldByName(field.Name).Set(result)
+										reflect.Indirect(objects.Index(j)).FieldByName(field.Name).Set(result)
 										break
 									}
 								}
@@ -71,7 +75,7 @@ func Preload(scope *Scope) {
 								value := getFieldValue(result, relation.ForeignKey)
 								objects := scope.IndirectValue()
 								for j := 0; j < objects.Len(); j++ {
-									object := objects.Index(j)
+									object := reflect.Indirect(objects.Index(j))
 									if equalAsString(getFieldValue(object, primaryName), value) {
 										f := object.FieldByName(field.Name)
 										f.Set(reflect.Append(f, result))
@@ -91,7 +95,7 @@ func Preload(scope *Scope) {
 								value := getFieldValue(result, associationPrimaryKey)
 								objects := scope.IndirectValue()
 								for j := 0; j < objects.Len(); j++ {
-									object := objects.Index(j)
+									object := reflect.Indirect(objects.Index(j))
 									if equalAsString(getFieldValue(object, relation.ForeignKey), value) {
 										object.FieldByName(field.Name).Set(result)
 										break
@@ -130,7 +134,7 @@ func (scope *Scope) getColumnAsArray(column string) (primaryKeys []interface{})
 	case reflect.Slice:
 		for i := 0; i < values.Len(); i++ {
 			value := values.Index(i)
-			primaryKeys = append(primaryKeys, value.FieldByName(column).Interface())
+			primaryKeys = append(primaryKeys, reflect.Indirect(value).FieldByName(column).Interface())
 		}
 	case reflect.Struct:
 		return []interface{}{values.FieldByName(column).Interface()}
diff --git a/preload_test.go b/preload_test.go
index 1107f234..2a0e967b 100644
--- a/preload_test.go
+++ b/preload_test.go
@@ -76,4 +76,12 @@ func TestPreload(t *testing.T) {
 	for _, user := range users {
 		checkUserHasPreloadData(user, t)
 	}
+
+	var users2 []*User
+	DB.Where("role = ?", "Preload").Preload("BillingAddress").Preload("ShippingAddress").
+		Preload("CreditCard").Preload("Emails").Find(&users2)
+
+	for _, user := range users2 {
+		checkUserHasPreloadData(*user, t)
+	}
 }
diff --git a/scope.go b/scope.go
index 076fc336..d1b11615 100644
--- a/scope.go
+++ b/scope.go
@@ -101,8 +101,13 @@ func (scope *Scope) PrimaryKeyField() *Field {
 		var indirectValue = scope.IndirectValue()
 
 		clone := scope
+		// FIXME
 		if indirectValue.Kind() == reflect.Slice {
-			clone = scope.New(reflect.New(indirectValue.Type().Elem()).Elem().Interface())
+			typ := indirectValue.Type().Elem()
+			if typ.Kind() == reflect.Ptr {
+				typ = typ.Elem()
+			}
+			clone = scope.New(reflect.New(typ).Elem().Interface())
 		}
 
 		for _, field := range clone.Fields() {