Fix source type is incorrect error for embedded many to many relationship

association.go

@@ -290,7 +290,9 @@ func (association *Association) Count() int {
 		)
 	}
 
-	query.Model(fieldValue).Count(&count)
+	if err := query.Model(fieldValue).Count(&count).Error; err != nil {
+		association.Error = err
+	}
 	return count
 }
 

join_table_handler.go

@@ -59,6 +59,7 @@ func (s *JoinTableHandler) Setup(relationship *Relationship, tableName string, s
 	s.TableName = tableName
 
 	s.Source = JoinTableSource{ModelType: source}
+	s.Source.ForeignKeys = []JoinTableForeignKey{}
 	for idx, dbName := range relationship.ForeignFieldNames {
 		s.Source.ForeignKeys = append(s.Source.ForeignKeys, JoinTableForeignKey{
 			DBName:            relationship.ForeignDBNames[idx],
@@ -67,6 +68,7 @@ func (s *JoinTableHandler) Setup(relationship *Relationship, tableName string, s
 	}
 
 	s.Destination = JoinTableSource{ModelType: destination}
+	s.Destination.ForeignKeys = []JoinTableForeignKey{}
 	for idx, dbName := range relationship.AssociationForeignFieldNames {
 		s.Destination.ForeignKeys = append(s.Destination.ForeignKeys, JoinTableForeignKey{
 			DBName:            relationship.AssociationForeignDBNames[idx],

join_table_test.go

@@ -80,3 +80,38 @@ func TestJoinTable(t *testing.T) {
 		t.Errorf("Should deleted all addresses")
 	}
 }
+
+func TestEmbeddedMany2ManyRelationship(t *testing.T) {
+	type EmbeddedPerson struct {
+		ID        int
+		Name      string
+		Addresses []*Address `gorm:"many2many:person_addresses;"`
+	}
+
+	type NewPerson struct {
+		EmbeddedPerson
+		ExternalID uint
+	}
+	DB.Exec("drop table person_addresses;")
+	DB.AutoMigrate(&NewPerson{})
+
+	address1 := &Address{Address1: "address 1"}
+	address2 := &Address{Address1: "address 2"}
+	person := &NewPerson{ExternalID: 100, EmbeddedPerson: EmbeddedPerson{Name: "person", Addresses: []*Address{address1, address2}}}
+	if err := DB.Save(person).Error; err != nil {
+		t.Errorf("no error should return when save embedded many2many relationship, but got %v", err)
+	}
+
+	if err := DB.Model(person).Association("Addresses").Delete(address1).Error; err != nil {
+		t.Errorf("no error should return when delete embedded many2many relationship, but got %v", err)
+	}
+
+	association := DB.Model(person).Debug().Association("Addresses")
+	if count := association.Count(); count != 1 || association.Error != nil {
+		t.Errorf("Should found one address, but got %v, error is %v", count, association.Error)
+	}
+
+	if association.Clear(); association.Count() != 0 {
+		t.Errorf("Should deleted all addresses")
+	}
+}

model_struct.go

@@ -219,6 +219,13 @@ func (scope *Scope) GetModelStruct() *ModelStruct {
 								subField.IsPrimaryKey = false
 							}
 						}
+
+						if subField.Relationship != nil && subField.Relationship.JoinTableHandler != nil {
+							if joinTableHandler, ok := subField.Relationship.JoinTableHandler.(*JoinTableHandler); ok {
+								joinTableHandler.Setup(subField.Relationship, joinTableHandler.TableName, reflectType, joinTableHandler.Destination.ModelType)
+							}
+						}
+
 						modelStruct.StructFields = append(modelStruct.StructFields, subField)
 					}
 					continue