Controller classes must exist as files (why??)

[uuf6429]

CI is relatively flexible, there's just one tiny major problem:

https://github.com/bcit-ci/CodeIgniter/blob/63d037565dd782795021dcbd3b1ca6f8c8a509e4/system/core/CodeIgniter.php#L355...L361

If a (custom) router returns controller classes that have already been loaded, but perhaps from a different location/namespace, there's no way to make it work. This seems like a very silly limitation.

The code referenced above shouldn't even be loading the class from the filesystem, let alone constructing some file path out of a class name. At the very least, this whole default logic would only make sense after checking class_exists().

---

In short, here's some backward-compatible improved version:

	if (empty($class))
	{
		$e404 = TRUE;
	}
	else
	{
		if (!class_exists($class) && file_exists(APPPATH.'controllers/'.$RTR->directory.$class.'.php') ) {
			require_once(APPPATH.'controllers/'.$RTR->directory.$class.'.php');
		}

PS: class_exists triggers autoloading, in the right scenario, thus avoid the rest of the file-checking-file-loading code.