From a4239efa7cac31d8dbcc83d0c08778a10e69604b Mon Sep 17 00:00:00 2001
From: Qiang Xue <qiang.xue@gmail.com>
Date: Thu, 18 Jul 2013 08:05:09 -0400
Subject: [PATCH] Fixes #637.

---
 framework/yii/db/ActiveRecord.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/framework/yii/db/ActiveRecord.php b/framework/yii/db/ActiveRecord.php
index 0b413fe..3ad5bd3 100644
--- a/framework/yii/db/ActiveRecord.php
+++ b/framework/yii/db/ActiveRecord.php
@@ -1256,6 +1256,9 @@ class ActiveRecord extends Model
 		$relation = $this->getRelation($name);
 
 		if ($relation->via !== null) {
+			if ($this->getIsNewRecord() || $model->getIsNewRecord()) {
+				throw new InvalidCallException('Unable to link models: both models must NOT be newly created.');
+			}
 			if (is_array($relation->via)) {
 				/** @var $viaRelation ActiveRelation */
 				list($viaName, $viaRelation) = $relation->via;