Should Regex constructor parameter be mandatory?

[weierophinney]

I can obtain a Regex validator from the ValidatorPluginManager like so:

$validatorManager = $container->get('ValidatorManager');
$validator = $validatorManager->get('regex', ['pattern' => '/abcd/i']);

However, if I attempt to obtain a Regex validator without the options (to configure it later) I received a PHP Fatal error:

$validatorManager = $container->get('ValidatorManager');
$validator = $validatorManager->get('regex');
$validator->setPattern('/abcd/i');

PHP Fatal error:  Uncaught ArgumentCountError: Too few arguments to function Zend\Validator\Regex::__construct(), 0 passed in <REDACTED>/vendor/zendframework/zend-servicemanager/src/Factory/InvokableFactory.php on line 30 and exactly 1 expected in <REDACTED>/vendor/zendframework/zend-validator/src/Regex.php:51
Stack trace:
#0 <REDACTED>/vendor/zendframework/zend-servicemanager/src/Factory/InvokableFactory.php(30): Zend\Validator\Regex->__construct()
#1 <REDACTED>/vendor/zendframework/zend-servicemanager/src/ServiceManager.php(758): Zend\ServiceManager\Factory\InvokableFactory->__invoke(Object(Zend\ServiceManager\ServiceManager), 'Zend\\Validator\\...', NULL)
#2 <REDACTED>/vendor/zendframework/zend-servicemanager/src/Servic in <REDACTED>/vendor/zendframework/zend-validator/src/Regex.php on line 51

Both the approaches of passing options to the ValidatorPluginManager and configuring the validator after invocation work fine for all validators except Regex. From what I can tell, the Regex validator is the only one in the zendframework/zend-validator package where the constructor parameter is mandatory:

/**
 * Sets validator options
 *
 * @param  string|Traversable $pattern
 * @throws Exception\InvalidArgumentException On missing 'pattern' parameter
 */
public function __construct($pattern)
{
    // ...
}

For all the other validators the contructor parameters are optional, which is exactly how the AbstractValidator describes it:

/**
 * Abstract constructor for all validators
 * A validator should accept following parameters:
 *  - nothing f.e. Validator()
 *  - one or multiple scalar values f.e. Validator($first, $second, $third)
 *  - an array f.e. Validator(array($first => 'first', $second => 'second', $third => 'third'))
 *  - an instance of Traversable f.e. Validator($config_instance)
 *
 * @param array|Traversable $options
 */
public function __construct($options = null)
{
    // ...
}

Everything works fine using the first approach above, and it may be a deliberate design decision for the Regex contructor parameter to be mandatory, but it appeared out of place to me so I thought it worth mentioning in case this was an oversight.

---

Originally posted by @mrobinsonuk at zendframework/zend-validator#200

[gsteel]

Regex constructor param is mandatory as of #280