Add additional methods for reflections that have attributes

Description

All currently attributable reflections have a single method relating to attributes.

getAttributes(?string $name = null, int $flags = 0): array

Additional methods for dealing with attributes would be a nice improvement and would simplify common approaches. I'm proposing the following methods.

getAttribute

Get a single instance of ReflectionAttribute, following the same rules as getAttributes, minus the fact that $name is required.

getAttribute(string $name, int $flags = 0): ?ReflectionAttribute

If more than one attribute matches, an exception should be thrown.

hasAttribute

Functionally identical to getAttribute, except it will return true if one or more matches are found, otherwise it returns false.

hasAttribute(string $name, int $flags = 0): bool

getNumberOfAttributes

Again, follows the same rules as getAttributes, but will return the number found. This particular method is based on the ReflectionFunctionAbstract::getNumberOfParameters method.

getNumberOfAttributes(?string $name = null, int $flags = 0): int

Commencez par localiser les implémentations existantes de getAttributes pour les réflexions auxquelles des attributs peuvent être associés, ainsi que les tests ReflectionAttribute associés. Utilisez ReflectionFunctionAbstract::getNumberOfParameters comme précédent de référence, puis vérifiez la correspondance, les flags, la gestion des doublons et les valeurs de retour des méthodes proposées pour tous les types de réflexion auxquels des attributs peuvent être associés.