Impruve ChangeUserName

Author: 6543

models/user.go

@@ -913,19 +913,19 @@ func ChangeUserName(u *User, newUserName string) (err error) {
 		return err
 	}
 
-	isExist, err := IsUserExist(0, newUserName)
-	if err != nil {
-		return err
-	} else if isExist {
-		return ErrUserAlreadyExist{newUserName}
-	}
-
 	sess := x.NewSession()
 	defer sess.Close()
 	if err = sess.Begin(); err != nil {
 		return err
 	}
 
+	isExist, err := isUserExist(sess, 0, newUserName)
+	if err != nil {
+		return err
+	} else if isExist {
+		return ErrUserAlreadyExist{newUserName}
+	}
+
 	if _, err = sess.Exec("UPDATE `repository` SET owner_name=? WHERE owner_name=?", newUserName, u.Name); err != nil {
 		return fmt.Errorf("Change repo owner name: %v", err)
 	}