Fixed sync bug

src/Jenssegers/Mongodb/Relations/BelongsToMany.php

@@ -170,6 +170,9 @@ class BelongsToMany extends EloquentBelongsToMany {
 
 		$query = $this->newParentQuery();
 
+		// Generate a new related query instance
+		$related = $this->related->newInstance();
+
 		// If associated IDs were passed to the method we will only delete those
 		// associations, otherwise all of the association ties will be broken.
 		// We'll return the numbers of affected rows when we do the deletes.
@@ -189,6 +192,9 @@ class BelongsToMany extends EloquentBelongsToMany {
 		{
 			$query->pull($this->otherKey, $id);
 		}
+		
+		// Remove the relation from the related model
+		$related->pull($this->foreignKey, $this->parent->getKey());
 
 		return count($ids);
 	}

tests/RelationsTest.php

@@ -209,7 +209,10 @@ class RelationsTest extends PHPUnit_Framework_TestCase {
 
         $user = User::with('clients')->find($user->_id);
 
-        // Assert there are now 4 client objects in the relationship
-        $this->assertCount(4, $user->clients);
+        // Assert there are now still 2 client objects in the relationship
+        $this->assertCount(2, $user->clients);
+		// Assert that the new relationships name start with synced
+		$this->assertStringStartsWith('synced', $user->clients[0]->name);
+		$this->assertStringStartsWith('synced', $user->clients[1]->name);
     }
 }