For a project of mine, I moved app/Resources into resources to keep more in line with the company project structure. On the way I had a few quirks, namely with the routing.

When having the following:

# resources/config/routing.yml
app:
    resource: '../../src/Infrastructure/Action'
    type:     'annotation'

In a regular application, this relative path is being located from app/Resources so it should result in app/Resources/../../src/Infrastructure/Action. Whilst the path does make sense (src/Infrastructure/Action exists), app/Resources does not exist so resolving this path e.g. with realpath() will fail.

One could get around that by using the @AppBundle notation, but this notation is not usable with .. so if AppBundle is not place at a higher level than src/Infrastructure/Action, e.g. when you have src/Infrastructure/Bundle/AppBundle.php, this trick cannot work.

When you get at that point, you either take the path of the least resistance and just create a app/Resources/.gitkeep file and don't care or you are a stubborn sore loser and try to keep going.

So here's how I eventually got around that: First override the file_locator service:

# resources/services.yml
services:
    file_locator:
        class: Symfony\Component\HttpKernel\Config\FileLocator
        arguments:
            - '@kernel'
            - '%kernel.root_dir%/../resources'

I don't know exactly where in the application this service is really used, but I do know it's used very early in the bootstrapping process so this in any case is not enough. Not finding a better solution, I changed:

// app/AppKernel.php

class AppKernel
{
    //...

    /**
     * @inheritdoc
     */
    public function locateResource($name, $dir = null, $first = true)
    {
        if (__DIR__.'/Resources' === $dir) {
            $dir = realpath(__DIR__.'/../resources');
        }
        
        return parent::locateResource($name, $dir, $first);
    }
}

I'm not sure is there something more elegant that could be done neither if this should be documented. If it should let me know where I'll be happy to do a PR about it, if you feel it's not worth it just close the issue.