Add sniff for Service Contracts

[kanduvisla]

Rule

According to this page there are some very specific rules for service contracts. For example:

• Valid object types include a fully qualified class name or a fully qualified interface name.
• Any parameters or return values of type array can be denoted by following any of the previous types by an empty set of square brackets []

Wouldn't it make sense to have a sniff for these things?

Reason

I come across a lot of service contracts that don't include FQCN and/or have an array return type instead of FQCN[]. This goes against the rules set by Magento and might also break future (web api) implementations (due to reflection).

Implementation

Not sure at this moment how to implement this, but it seems to me that this can be done with a new sniff.

[kanduvisla]

This is a small POC for a FQCN in the method signature:

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;

class ServiceContractSniff implements Sniff
{
    private const NON_OBJECTS = [
        'int',
        'integer',
        'string',
        'bool',
        'boolean',
        'float',
        'array',
        'object',
        'resource',
    ];

    public function register()
    {
        return [
            T_INTERFACE,
        ];
    }

    public function process(File $phpcsFile, $stackPtr)
    {
        $tokens = $phpcsFile->getTokens();
        if (preg_match('/.*\/Api\/(Data\/)?.*/', $phpcsFile->getFilename()) === 1) {
            foreach ($tokens as $token) {
                if ($token['type'] === 'T_FUNCTION') {
                    for ($index = $token['parenthesis_opener'] + 1; $index < $token['parenthesis_closer']; $index += 1) {
                        if ($tokens[$index]['type'] === 'T_STRING') {
                            $type = $tokens[$index]['content'];
                            if (!in_array($type, self::NON_OBJECTS)) {
                                if (strpos($type, '\\') !== 0 && !class_exists($type)) {
                                    $phpcsFile->addError(
                                        'Parameter "%s" should be referenced as a fully qualified class name',
                                        $stackPtr,
                                        'Found',
                                        $type
                                    );
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

Disclaimer: this is in conjunction with the SlevomatCodingStandard.Namespaces.FullyQualifiedClassNameInAnnotation sniff restricted to the Api-folder