Class deprecation via class loader

[beberlei]

Instead of complicated in file approaches, we could provide a deprecation class loader that just checks and triggers deprecations and then delegates autoloading further to Composer.

This could hook into Composer as a plugin and generate a map of deprecated classes from all installed packages, and then in your code you would only prepend the autoloader:

if ($isDevMode) {
    spl_autoload_register(['DeprecationLoader', 'loadClass'], true, true);
}

[nicolas-grekas]

Please don't do this in this lib, that'd be past its domain to me.
This concern is better delegated to frameworks.

[beberlei]

@nicolas-grekas the reason is that the if (false) or so approach for deprecating classes breaks for some of our users with preloading and we are looking to deprecate old classes a different way.

See doctrine/persistence#97