From 0546b59743ec2759051cb921a4dc5f7c31f36e3d Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Wed, 22 Jul 2020 11:28:00 +0800
Subject: [PATCH] Fix save many2many associations with UUID primary key, close
 #3182

---
 callbacks/create.go    |  9 ++++++++-
 tests/postgres_test.go | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/callbacks/create.go b/callbacks/create.go
index eecb80a1..de5bf1f8 100644
--- a/callbacks/create.go
+++ b/callbacks/create.go
@@ -149,10 +149,17 @@ func CreateWithReturning(db *gorm.DB) {
 
 						for rows.Next() {
 						BEGIN:
+							reflectValue := db.Statement.ReflectValue.Index(int(db.RowsAffected))
 							for idx, field := range fields {
-								fieldValue := field.ReflectValueOf(db.Statement.ReflectValue.Index(int(db.RowsAffected)))
+								fieldValue := field.ReflectValueOf(reflectValue)
+
 								if onConflict.DoNothing && !fieldValue.IsZero() {
 									db.RowsAffected++
+
+									if int(db.RowsAffected) >= db.Statement.ReflectValue.Len() {
+										return
+									}
+
 									goto BEGIN
 								}
 
diff --git a/tests/postgres_test.go b/tests/postgres_test.go
index 98302d87..ab47a548 100644
--- a/tests/postgres_test.go
+++ b/tests/postgres_test.go
@@ -37,3 +37,36 @@ func TestPostgres(t *testing.T) {
 		t.Errorf("No error should happen, but got %v", err)
 	}
 }
+
+type Post struct {
+	ID         uuid.UUID `gorm:"primary_key;type:uuid;default:uuid_generate_v4()"`
+	Title      string
+	Categories []*Category `gorm:"Many2Many:post_categories"`
+}
+
+type Category struct {
+	ID    uuid.UUID `gorm:"primary_key;type:uuid;default:uuid_generate_v4()"`
+	Title string
+	Posts []*Post `gorm:"Many2Many:post_categories"`
+}
+
+func TestMany2ManyWithDefaultValueUUID(t *testing.T) {
+	if DB.Dialector.Name() != "postgres" {
+		t.Skip()
+	}
+
+	DB.Migrator().DropTable(&Post{}, &Category{}, "post_categories")
+	DB.AutoMigrate(&Post{}, &Category{})
+
+	post := Post{
+		Title: "Hello World",
+		Categories: []*Category{
+			{Title: "Coding"},
+			{Title: "Golang"},
+		},
+	}
+
+	if err := DB.Create(&post).Error; err != nil {
+		t.Errorf("Failed, got error: %v", err)
+	}
+}