Incorrectly generated autoload files when installing to a root level directory

[punkstar]

When installing Magento to a root level directory (e.g. /magento) the files generated by Composer contain invalid paths and result in the inability to load Magento\Framework\Component\ComponentRegistrar, bricking the application.

This was discovered when installing Magento into a top level directory inside of a docker container.

The problem appears to be in the generated vendor/composer/autoload_static.php file. The $files property has duplicated file prefixes, e.g:

public static $files = array (
    '07ec02c7e667fdcb3e30c02cc772b743' => __DIR__ . '/..' . __DIR__ . '/../..' . '/framework/registration.php',
    '3d9d6f82d2fa20ee6036e230ae5c2fff' => __DIR__ . '/..' . __DIR__ . '/../..' . '/module-ui/registration.php',
    'fbcc86ec9185efc54c1e806bbb33c954' => __DIR__ . '/..' . __DIR__ . '/../..' . '/module-store/registration.php',

I'd expect these lines to look like the following (and they do, when not using a stupid directory):

public static $files = array (
    '07ec02c7e667fdcb3e30c02cc772b743' => __DIR__ . '/..' . '/magento/framework/registration.php',
    '3d9d6f82d2fa20ee6036e230ae5c2fff' => __DIR__ . '/..' . '/magento/module-ui/registration.php',
    'fbcc86ec9185efc54c1e806bbb33c954' => __DIR__ . '/..' . '/magento/module-store/registration.php',

This may very well be a problem with composer, but I'd like to confirm that Magento isn't doing something to the autoload map generation before heading over there.

Steps to reproduce

Tested with PHP 7.0.3 and 7.0.7:

composer create-project --repository-url=https://repo.magento.com/ \
    magento/project-community-edition \
    /magento
chmod +x /magento/bin/magento
/magento/bin/magento list

Expected result

Magento CLI version 2.0.7

Usage:
 command [options] [arguments]

Options:
 --help (-h)           Display this help message

 ... trimmed out some commands ...

 setup:performance:generate-fixtures       Generates fixtures
 setup:rollback                            Rolls back Magento Application codebase, media and database
 setup:store-config:set                    Installs the store configuration
 setup:uninstall                           Uninstalls the Magento application
 setup:upgrade                             Upgrades the Magento application, DB data, and schema

Actual result

PHP Fatal error:  Uncaught Error: Class 'Magento\Framework\Component\ComponentRegistrar' not found in /magento/vendor/magento/framework/registration.php:7
Stack trace:
#0 /magento/vendor/composer/autoload_real.php(71): require()
#1 /magento/vendor/composer/autoload_real.php(61): composerRequire88e4545d1b520c2793b1dd2b497ba4e0('07ec02c7e667fdc...', '/magento/vendor...')
#2 /magento/vendor/autoload.php(7): ComposerAutoloaderInit88e4545d1b520c2793b1dd2b497ba4e0::getLoader()
#3 /magento/app/autoload.php(21): include('/magento/vendor...')
#4 /magento/app/bootstrap.php(30): require_once('/magento/app/au...')
#5 /magento/bin/magento(15): require('/magento/app/bo...')
#6 {main}
  thrown in /magento/vendor/magento/framework/registration.php on line 7

Fatal error: Uncaught Error: Class 'Magento\Framework\Component\ComponentRegistrar' not found in /magento/vendor/magento/framework/registration.php:7
Stack trace:
#0 /magento/vendor/composer/autoload_real.php(71): require()
#1 /magento/vendor/composer/autoload_real.php(61): composerRequire88e4545d1b520c2793b1dd2b497ba4e0('07ec02c7e667fdc...', '/magento/vendor...')
#2 /magento/vendor/autoload.php(7): ComposerAutoloaderInit88e4545d1b520c2793b1dd2b497ba4e0::getLoader()
#3 /magento/app/autoload.php(21): include('/magento/vendor...')
#4 /magento/app/bootstrap.php(30): require_once('/magento/app/au...')
#5 /magento/bin/magento(15): require('/magento/app/bo...')
#6 {main}
  thrown in /magento/vendor/magento/framework/registration.php on line 7

Known workarounds

1. Don't be an idiot. Don't use a root level directory! 🤔

[wert2all]

As I understand Your issue was fixed into
#meanbee/docker-magento2#25

is it correct?

[punkstar]

@wert2all Yes, that was my work around for the issue.

[BaDos]

Hi @punkstar

Thank you for reporting.
We've created internal ticket MAGETWO-58389 to resolve this issue.