fix bug

Author: ziaratban

src/ActiveQuery.php

@@ -93,6 +93,16 @@ public function init()
         $this->trigger(self::EVENT_INIT);
     }
 
+    /**
+     * returns mongodb connection object from `modelClass` if `$db` is null otherwise returns `$db`
+     * @param null|Connection your custom connection object
+     * @return Connection returns a connection object base on input
+    */
+    protected function finalConObj($db){
+        $modelClass = $this->modelClass;
+        return $db === null ? $modelClass::getDb() : $db;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -133,7 +143,7 @@ public function prepare()
      */
     public function all($db = null)
     {
-        return parent::all($db === null ? $this->modelClass::GetDb() : null);
+        return parent::all($this->finalConObj($db));
     }
 
     /**
@@ -146,7 +156,7 @@ public function all($db = null)
      */
     public function one($db = null)
     {
-        $row = parent::one($db === null ? $this->modelClass::GetDb() : null);
+        $row = parent::one($this->finalConObj($db));
         if ($row !== false) {
             $models = $this->populate([$row]);
             return reset($models) ?: null;
@@ -167,7 +177,7 @@ public function one($db = null)
      */
     public function modify($update, $options = [], $db = null)
     {
-        $row = parent::modify($update, $options, $db === null ? $this->modelClass::GetDb() : null);
+        $row = parent::modify($update, $options, $this->finalConObj($db));
         if ($row !== null) {
             $models = $this->populate([$row]);
             return reset($models) ?: null;
@@ -182,15 +192,12 @@ public function modify($update, $options = [], $db = null)
      */
     public function getCollection($db = null)
     {
-        /* @var $modelClass ActiveRecord */
-        if ($db === null) {
-            $db = $this->modelClass::getDb();
-        }
         if ($this->from === null) {
-            $this->from = $this->modelClass::collectionName();
+            $modelClass = $this->modelClass;
+            $this->from = $modelClass::collectionName();
         }
 
-        return $db->getCollection($this->from);
+        return $this->finalConObj($db)->getCollection($this->from);
     }
 
     /**