php 调试利器： debug_backtrace

debug_backtrace是一个bug工具，如果加入到某个类函数里面，那么可以看到调用这个函数的类方法，依次上推，直至index.php
下面是我打印的一个yii2组件的日志：

public function actionBootstrap($app){
    
    $d = debug_backtrace();
    foreach($d as $e){
      $function = $e['function'];
      $class = $e['class'];
      $file = $e['file'];
      $line = $e['line'];
      echo $file.'('.$line.'),'.
      $class.'::'.$function.'()<br/>';
    }
    echo '<br/><br/>';

输出的日志为：

(),fecshop\services\Store::actionBootstrap()
/www/web/develop/fecshop/vendor/fancyecommerce/fecshop/services/Service.php(58),::call_user_func_array()
/www/web/develop/fecshop/vendor/fancyecommerce/fecshop/components/Store.php(22),fecshop\services\Service::__call()
/www/web/develop/fecshop/vendor/fancyecommerce/fecshop/components/Store.php(22),fecshop\services\Store::bootstrap()
/www/web/develop/fecshop/vendor/yiisoft/yii2/base/Application.php(316),fecshop\components\Store::bootstrap()
/www/web/develop/fecshop/vendor/yiisoft/yii2/web/Application.php(66),yii\base\Application::bootstrap()
/www/web/develop/fecshop/vendor/yiisoft/yii2/base/Application.php(267),yii\web\Application::bootstrap()
/www/web/develop/fecshop/vendor/yiisoft/yii2/base/Object.php(107),yii\base\Application::init()
/www/web/develop/fecshop/vendor/yiisoft/yii2/base/Application.php(206),yii\base\Object::__construct()
/www/web/develop/fecshop/appfront/web/index.php(44),yii\base\Application::__construct()

这样就可以记录出来这个函数被调用的位置。