Prefix dependencies with PHP-Scoper

[swissspidy]

All the production dependencies required by Plugin Check are prefixed and stored in vendor-prefixed. This includes:

• afragen/wordpress-plugin-readme-parser
• plugin-check/phpcs-sniffs
• squizlabs/php_codesniffer

This avoids any autoloading conflicts in case another plugin uses the same dependencies.

The plugin's own classes are autoloaded with a new slim autoloader in includes/vendor. No actual dependencies are in there, it's just a classmap.

For afragen/wordpress-plugin-readme-parser there is a special case: if the plugin is running on WordPress.org, the original and unprefixed WordPressdotorg\Plugin_Directory\Readme\Parser is available, so there is a class_exists check to use that one if available.

Unfortunately right now requires dependencies to be prefixed manually by installing PHP-Scoper in that other directory & running composer prefix-dependencies

Fixes #328

[swissspidy]

@ernilambar FWIW the issue is that the latest PHP-Scoper requires PHP 8.2. This could be mitigated by installing that dependency with PHP 8.2 separate from the others, run the prefixing, then downgrade again.

[swissspidy]

@ernilambar I think it's very close now, after having fixed most of the namespace/autoloader issues. The last one seems to be specifically Fatal error: Cannot declare class WordPress\Plugin_Check\Vendor\WordPressVIPMinimum\Sniffs\Sniff, because the name is already in use in /var/www/html/wp-content/plugins/plugin-check/vendor-prefixed/vendor/automattic/vipwpcs/WordPressVIPMinimum/Sniffs/Sniff.php in unit tests. Probably the same thing that also causes some Behat failures.

Don't yet know why because it doesn't really happen to me locally.