Let's say API.php contains:
public function test($idSite = null)
Unless the method is called with idSite non-empty, Piwik returns:
<error message="The parameters are not valid. The method called requires 0 parameters. Please check your URL and the method API."/>
why wontfix? it sounds like a bug..
The exception is generated in the check for null parameters. So, I assumed this was by design/intentional.
In , fixes #953 - API doesn't handle default null parameters; remove checkParametersAreNotNull