Differences Symfony ArgumentResolver VS ParamConverter

When writing Symfony Applications we have the choice to use TypeHinting in our Controller Actions. In many cases Symfony provides "magic" parameter conversions which will examine the request and produce a model of the parameter class. This can be achieved by an ArgumentResolver or ParamConverter.

Both are using more or less the same (regarding the result). So which one should we use?

First: ArgumentResolver is the more recent implementation which comes with the latest Symfony Frameworks. For the ParamConverter we need to add a dependency from SensioLabs (the extra bundle). So, this can already be a hint for you to decide which one to use.

Second: A ParamConverter need to be explicitly added as an Attribute or Annotation to your action. ArgumentResolvers work  "in the background". If you don't mind a little more boilerplate code, you can use both. Otherwise use ArgumentResolvers.

Third: ArgumentResovler, even if is now part of Symfony, do not provide the same default implementations as a ParamConverter. For instance there is a ready to use ParamConverter for Doctrine entities. This can be very helpful, especially when you are trying to go fast on a project (probably MVP).