related with plugin system

main.go

@@ -120,17 +120,17 @@ func (s *DB) Assign(attrs ...interface{}) *DB {
 func (s *DB) First(out interface{}, where ...interface{}) *DB {
 	scope := s.clone().NewScope(out)
 	scope.Search = scope.Search.clone().order(scope.PrimaryKey()).limit(1)
-	return scope.inlineCondition(where).callCallbacks(s.parent.callback.queries).db
+	return scope.inlineCondition(where...).callCallbacks(s.parent.callback.queries).db
 }
 
 func (s *DB) Last(out interface{}, where ...interface{}) *DB {
 	scope := s.clone().NewScope(out)
 	scope.Search = scope.Search.clone().order(scope.PrimaryKey() + " DESC").limit(1)
-	return scope.inlineCondition(where).callCallbacks(s.parent.callback.queries).db
+	return scope.inlineCondition(where...).callCallbacks(s.parent.callback.queries).db
 }
 
 func (s *DB) Find(out interface{}, where ...interface{}) *DB {
-	return s.clone().NewScope(out).inlineCondition(where).callCallbacks(s.parent.callback.queries).db
+	return s.clone().NewScope(out).inlineCondition(where...).callCallbacks(s.parent.callback.queries).db
 }
 
 func (s *DB) Row() *sql.Row {
@@ -150,7 +150,7 @@ func (s *DB) Scan(dest interface{}) *DB {
 func (s *DB) FirstOrInit(out interface{}, where ...interface{}) *DB {
 	c := s.clone()
 	if c.First(out, where...).Error == RecordNotFound {
-		c.NewScope(out).inlineCondition(where).initialize()
+		c.NewScope(out).inlineCondition(where...).initialize()
 	} else {
 		c.NewScope(out).updatedAttrsWithValues(convertInterfaceToMap(s.search.assignAttrs), false)
 	}
@@ -160,7 +160,7 @@ func (s *DB) FirstOrInit(out interface{}, where ...interface{}) *DB {
 func (s *DB) FirstOrCreate(out interface{}, where ...interface{}) *DB {
 	c := s.clone()
 	if c.First(out, where...).Error == RecordNotFound {
-		c.NewScope(out).inlineCondition(where).initialize().callCallbacks(s.parent.callback.creates)
+		c.NewScope(out).inlineCondition(where...).initialize().callCallbacks(s.parent.callback.creates)
 	} else if len(s.search.assignAttrs) > 0 {
 		c.NewScope(out).Set("gorm:update_interface", s.search.assignAttrs).callCallbacks(s.parent.callback.updates)
 	}
@@ -219,8 +219,7 @@ func (s *DB) Model(value interface{}) *DB {
 }
 
 func (s *DB) Related(value interface{}, foreign_keys ...string) *DB {
-	old_data := s.Value
-	return s.do(value).related(old_data, foreign_keys...).db
+	return s.clone().NewScope(s.Value).related(value, foreign_keys...).db
 }
 
 func (s *DB) Pluck(column string, value interface{}) *DB {

scope.go

@@ -94,14 +94,21 @@ func (scope *Scope) PrimaryKeyValue() interface{} {
 }
 
 func (scope *Scope) HasColumn(name string) bool {
+	_, result := scope.FieldByName(name)
+	return result
+}
+
+func (scope *Scope) FieldByName(name string) (interface{}, bool) {
 	data := reflect.Indirect(reflect.ValueOf(scope.Value))
 
 	if data.Kind() == reflect.Struct {
-		return data.FieldByName(name).IsValid()
-	} else if data.Kind() == reflect.Slice {
-		return reflect.New(data.Type().Elem()).Elem().FieldByName(name).IsValid()
+		if field := data.FieldByName(name); field.IsValid() {
+			return field.Interface(), true
 		}
-	return false
+	} else if data.Kind() == reflect.Slice {
+		return nil, reflect.New(data.Type().Elem()).Elem().FieldByName(name).IsValid()
+	}
+	return nil, false
 }
 
 func (scope *Scope) updatedAttrsWithValues(values map[string]interface{}, ignoreProtectedAttrs bool) (results map[string]interface{}, hasUpdate bool) {
@@ -430,3 +437,26 @@ func (scope *Scope) count(value interface{}) *Scope {
 	scope.Err(scope.row().Scan(value))
 	return scope
 }
+
+func (scope *Scope) typeName() string {
+	value := reflect.Indirect(reflect.ValueOf(scope.Value))
+	if value.Kind() == reflect.Slice {
+		return value.Type().Elem().Name()
+	} else {
+		return value.Type().Name()
+	}
+}
+
+func (scope *Scope) related(value interface{}, foreignKeys ...string) *Scope {
+	toScope := scope.New(value)
+
+	for _, foreignKey := range append(foreignKeys, toScope.typeName()+"Id", scope.typeName()+"Id") {
+		if foreignValue, ok := scope.FieldByName(foreignKey); ok {
+			return toScope.inlineCondition(foreignValue).callCallbacks(scope.db.parent.callback.queries)
+		} else if toScope.HasColumn(foreignKey) {
+			sql := fmt.Sprintf("%v = ?", scope.quote(toSnake(foreignKey)))
+			return toScope.inlineCondition(sql, scope.PrimaryKeyValue()).callCallbacks(scope.db.parent.callback.queries)
+		}
+	}
+	return scope
+}

scope_condition.go

@@ -243,7 +243,7 @@ func (scope *Scope) prepareQuerySql() {
 	return
 }
 
-func (scope *Scope) inlineCondition(values []interface{}) *Scope {
+func (scope *Scope) inlineCondition(values ...interface{}) *Scope {
 	if len(values) > 0 {
 		scope.Search = scope.Search.clone().where(values[0], values[1:]...)
 	}