When running PHP Code sniffer with the Magento 2 standard included in the dev tools on my code I receive the Ambiguous type array is NOT recommended warning quite frequently, is there a way to solve the warning?

php vendor/bin/phpcs --warning-severity=1 \ --standard=dev/tests/static/testsuite/Magento/Test/Php/_files/phpcs/ruleset.xml \ -d memory_limit=1024M --encoding=utf-8 --extensions=php,phtml \ vendor/vendorName/moduleName/


  • 24 | WARNING | Ambiguous type "array" for @var is NOT recommended
  • 42 | WARNING | Ambiguous type "array" for @return is NOT recommended
  • 63 | WARNING | Ambiguous type "array" for @return is NOT recommended

Entirely depends on context. The preferred solution would be one of two things (or possibly a combination of both):

  1. If your array is a set of values all having consistent type, specify that sub-type explicitly. For instance, if you have a $param array of \My\Class\Model\Something instances, rather than array $param, your type definition should be \My\Class\Model\Something[] $param.
  2. If your array is not a set of consistent type, but always follows the same pattern (it should!), convert it into an object with a defined interface.

For #2: Say you have an array to hold multiple values for the response:

$response = [
    'message' => 'Success',
    'error' => false,
return $response;

Rather than returning this array (type array), you should turn that into an object:

class Response extends \Magento\Framework\DataObject implements ResponseInterface
    public function setMessage(string $message)
        return $this->setData('message', $message);

    public function getMessage()
        return $this->getData('message');

    public function setError(bool $error)
        return $this->setData('error', $error);

    public function getError()
        return $this->getData('error');

And then use dependency injection to inject a ResponseFactory (as $this->responseFactory), then:

$response = $this->responseFactory->create();
return $response;

And suddenly you have a defined interface, and every bit of code knows that response is going to be an instance of Response, with a message and an error flag, as well as the types of each, and how to get to them.

By defining types, you remove ambiguity and the possibility of anomalous behavior.

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