[FIXED] How to check if composer's autoloader is being used?

Issue

I'm developing a certain PHP framework for WordPress, and I want to give my users the option to use composer to install it as a package, or to install it manually. If composer is used, then a psr-4 class autoloader handles everything. If not, then all files must be loaded manually during the framework's bootstrapping process.

Is there a safe way to check whether composer's autoloader is being used in a given WordPress environment?

Currently i'm using:

if( !class_exists('Composer\\Autoload\\ClassLoader') )
{
    // Manually include files if composer is not used.
    require_once 'some/files.php';
}

However, if in a given WordPress environment there is a plugin that uses composer internally, then the above if statement will return true even though other plugins have no access to it.

Solution

The solution, as it turns out, is quite simple. You need to create 2 different bootstrapping files, say manual-bootstrap.php and composer-bootstrap.php. Then add the following lines to composer.json:

"autoload": {
    "files": ["composer-bootstrap.php"]
}

composer-bootstrap.php will only be called if composer is used to load the framework as a dependency. Users that want to load the framework manually will use manual-bootstrap.php instead.

Answered By - Yoav Kadosh