Unbundle the `decorator` dependency, or at least upgrade it

Hi,

In #91 years ago, it was decided to add the decorator to fix a problem. Back then choices was made to not add a new dependency, but really bundle the only decorar file needed. Distributions (in my case Fedora) usually prefer to rely on the actual package than bundled dependencies. Fedora does apply a patch to unbundle decorator, maybe other distro do that too.

Do we still want to avoid dependencies in 2025 ? I have seen other discussions where it was discussed adding a protobuf dependency, which pulls many more dependencies, so isn't ok now to depend on decorator ?

If not, would it make sense at least to upgrade it ? By doing so, you hit the issue that decorator.getargspec has been removed years ago. In python 3 there is now inspect.getfullargspec which is not strictly equivalent but does provide a similar feature. Fedora uses a minimal patch here: https://src.fedoraproject.org/rpms/python-prometheus_client/blob/rawhide/f/0001-Remove-the-bundled-decorator-package.patch#_506 but tries to avoid adding much code, most likely the "real" change is more verbose.

Aucun fichier du dépôt ni aucun test n’est nommé dans l’issue. Commencez par examiner l’implémentation actuelle du décorateur incluse et le patch d’unbundling de Fedora indiqué par le lien, puis déterminez si le projet dépendra du package externe ou conservera une version incluse mise à jour. La tâche est terminée lorsque la stratégie de dépendances choisie fonctionne avec les versions actuelles de Python et que sa compatibilité est couverte par la suite de tests existante.