Fall back to parent directory if composer.json not found in module directory

[schmengler]

Description

This change allows modules to follow the pds/skeleton standard and have their source code in a src subdirectory of the repository.

Manual testing scenarios

1. create a module with composer.json and registration.php in the root directory and source code in src

   registration.php

   \Magento\Framework\Component\ComponentRegistrar::register(
       \Magento\Framework\Component\ComponentRegistrar::MODULE,
       'Vendor_Module',
       __DIR__ . '/src'
   );
   

   composer.json

     "autoload": {
       "files": [
         "registration.php"
       ],
       "psr-4": {
         "Vendor\\Module\\": "src"
       }
     },
     "suggest": {
       "vendor/module-sample-data": "Sample Data version:1.0.0"
     },
   

2. call bin/magento sampledata:deploy and see if vendor/module-sample-data is going to be installed.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[schmengler]

Another case where Magento reads composer.json files from modules is \Magento\Framework\Module\PackageInfo. This is a bit more complicated to change and test, so it would be a different PR

[fooman]

hey @schmengler love the direction of this PR. It is currently already possible to have the code under src/ with the registration file sitting under src/registration.php and then reference it from a root composer.json file as src/registration.php. The only place where this falls over as you mentioned is in \Magento\Framework\Module\PackageInfo (I currently solve it by providing an alternative src/composer.json which is not ideal).

I had looked into this here #3400. My current thought to solve this across the board would be to add a new optional param to \Magento\Framework\Component\ComponentRegistrar::register() which holds the composer.json file location which can then be used in PackageInfo to find the correct file. If empty it's assumed to be in the same folder as registration.php (aka current behaviour).

[schmengler]

@fooman Good idea with the optional parameter, that would give even more flexibility! Putting registration.php in src was my first approach too but I remember this caused trouble because of assumptions in Magento. Duplicating composer.json is a workaround but that cannot be the solution

[okorshenko]

Hi @schmengler thank you for your contribution. Could you please fix broken static tests. Also we are getting Fatal error with this changes.
PHP Fatal error: Uncaught Error: Cannot instantiate interface Magento\Framework\Filesystem\DriverInterface
Could you please verify your changes. Thank you

[Ctucker9233]

@magento-team can this be ported to 2.2?