Purpose of magento\generated\metadata\global.php file and is it safe to delete this file?

Question

I encountered the following issue when I have moved Magento 2 module into production with the command setup:di: compile

Uncaught Error: Call to a member function setActive() on boolean in /opt/bitnami/apps/magento/htdocs/vendor/magento/module-backend/Model/View/Result/Page.php:27\nStack trace: /opt/bitnami/apps/magento/htdocs/generated/code/Magento/Backend/Model/View/Result/Page/Interceptor.php(24): Magento\Backend\Model\View\Result\Page->setActiveMenu('...')

I found a solution to delete magento\generated\metadata\global.php file which worked.

Does anyone know the purpose of global.php file and is it safe to delete it?

Thanks in advance.

Answer 1

As the documentation says

"The code compiler creates generated/metadata/global.php, which is a PHP serialized map of all constructor definitions mixed with object linking configuration defined in di.xml. di.xml is the dependency injection configuration. There is a global app/etc/di.xml and there can one defined for every module ."

Answer 2

I do not recommend to delete the file, as Magento is running in Developer mode without it, as ConfigLoader\Compiled::getFilePath(Area::AREA_GLOBAL) resolves to /generated/metadata/global.php:

 private function getMode()
{
    if (file_exists(ConfigLoader\Compiled::getFilePath(Area::AREA_GLOBAL))) {
        return Compiled::MODE;
    }

    return Developer::MODE;
}

Answer 3

Well looking into M2 core if the global.php is missing it runs the environment in developer mode rather than compiled mode (check vendor/magento/framework/App/EnvironmentFactory.php getMode method). I have no idea what that means in terms of performance and why running in compiled mode causes the error you mentioned since none of this is documented...