Q:

Multiple actions were found on controller after upgrading to mvc4 rc

We have been using mvc webapi beta and are trying to upgrade to the rc.  
We have the following routes (only constraint is to verify that {id} is an integer):
"Api Verb with SubAction"   api/{controller}/{id}/{action}
"Api Verb with Id"          api/{controller}/{id}
"Api Verb without Id"       api/{controller}
"Api Action with Id"        api/{controller}/{action}/{id}
"Api Action without Id"     api/{controller}/{action}

And the following controller actions
public IList<PaymentMethodViewModel> GetList()
{}

public HttpResponseMessage Get(Guid id)
{}

[ActionName("Details")]
public IList<RecurrenceModel> GetDetails(Guid id)
{}

api/mycontroller, api/mycontroller/1, api/mycontroller/1/details all returned correctly in the beta.  However, after upgrading to MVC4 RC api/mycontroller/1, api/mycontroller/1/details return "Multiple actions were found that match the request:"

A:

Yes I had similar problems and failed to find a proper reason. It is obviously due to the changes to the routing implementation but the code for it is quite hefty and I didn't have the time to go over it yet.
Given that it will continue to evolve at this pace, it may be best to depend on built-in routing mechanism only for default {controller}/{id} style of routing and AttributeRouting for anything else.

