找不到Silex \\ Route :: setPath（）

Question

I'm working on a new Silex project and am having trouble mounting a route to my Controller providers. I have successfully done this before in another project, but now when I put the following routes in app.php :

$app->mount('/', new CommonController());
$app->mount('/feeds', new FeedsController());
$app->mount('/admin', new AdminController());

I receive a fatal error: Fatal error: Call to undefined method Silex\\Route::setPath() in [root]/vendor/symfony/routing/Symfony/Component/Routing/RouteCollection.php on line 255

EDIT:
The error does not get thrown when I mount the root route. Only when I add /feeds or /admin .
END EDIT

I can't figure out where this might be coming from - I've searched my other working project for this function definition, but it's nowhere to be found in the code. I think I might be missing a library in composer.json but I'm not sure which one it might be - the file is almost identical across both projects:

WORKING composer.json:

{
    "name"        : "lyrixx/Silex-Kitchen-Edition",
    "type"        : "library",
    "description" : "A Silex Edition. This project is a base for your silex applications.",
    "keywords"    : ["framework"],
    "homepage"    : "http://lyrixx.github.com/Silex-Kitchen-Edition/",
    "license"     : "MIT",
    "authors"     : [
        {
            "name"  : "Grégoire Pineau",
            "email" : "lyrixx@lyrixx.info"
        }
    ],
    "repositories": [
        {
            "type": "package",
            "package": {
                "name"    : "twitter/bootstrap",
                "version" : "2.0.4",
                "source"  : {
                    "url"       : "https://github.com/twitter/bootstrap.git",
                    "type"      : "git",
                    "reference" : "v2.0.4"
                }
            }
        }
    ],
    "require": {
        "php"                     : ">=5.3.3",
        "silex/silex"             : "dev-master",
        "twig/twig"               : "1.*",
        "monolog/monolog"         : "1.0.*",
        "symfony/form"            : "2.1.*",
        "symfony/translation"     : "2.1.*",
        "symfony/twig-bridge"     : "2.1.*",
        "symfony/validator"       : "2.1.*",
        "symfony/yaml"            : "2.1.*",
        "symfony/config"          : "2.1.*",
        "kriswallsmith/assetic"   : "1.0.*",
        "twitter/bootstrap"       : "2.0.4",
        "doctrine/dbal"           : "2.2.*",
        "symfony/security"        : "2.1.*",
        "fate/silex-extensions"   : "dev-master",
        "michelf/php-markdown"    : "1.3.*@dev",
        "swiftmailer/swiftmailer" : ">=4.1.2,<4.2-dev"
    },
    "require-dev": {
        "symfony/dom-crawler"   : "2.1.*",
        "symfony/css-selector"  : "2.1.*",
        "symfony/browser-kit"   : "2.1.*"
    },
    "minimum-stability" : "dev",
    "scripts": {
        "post-install-cmd": "Lx\\Composer\\Script::postInstall"
    },
    "autoload": {
        "psr-0": {
            [autoload routes defined here]
        }
    }
}

"BROKEN" composer.json:

{
    "require": {
        "php"                     : ">=5.3.3",
        "silex/silex"             : "dev-master",
        "twig/twig"               : "1.*",
        "monolog/monolog"         : "1.0.*",
        "symfony/form"            : "2.1.*",
        "symfony/translation"     : "2.1.*",
        "symfony/twig-bridge"     : "2.1.*",
        "symfony/validator"       : "2.1.*",
        "symfony/yaml"            : "2.1.*",
        "symfony/config"          : "2.1.*",
        "kriswallsmith/assetic"   : "1.0.*",
        "twitter/bootstrap"       : "2.0.*",
        "doctrine/dbal"           : "2.2.*",
        "fate/silex-extensions"   : "dev-master",
        "swiftmailer/swiftmailer" : ">=4.1.2,<4.2-dev"
    },
    "autoload": {
        "psr-0": {
            [autoload routes defined here]
        }
    }
}

Again, this may not even be the root cause of my issue, just my gut feeling. Can anyone decipher what's going on here?

SECOND EDIT: FeedsController.php

<?php

namespace Controllers;

use Controllers\CommonController;
use Silex\Application;
use Symfony\Component\HttpFoundation\Request;

class FeedsController extends CommonController
{

    public function connect(Application $app)
    {
        $controller = $app['controllers_factory'];

        $controller->get('/', function (Request $request, Application $app)
        {
            return 'Yay!';
        });

        return $controller;
    }
}

Answer 1

I've narrowed the problem down to a bad library in my vendors folder, though I can't be sure which one it is. I copied my correctly working vendors folder to my broken one and everything started working.

I will update this answer once I know what the exact issue was.