When clicking on “Add a role” in the Users administration, I got the following exception:

System.NullReferenceException: Object reference not set to an instance of an object.
at Orchard.Roles.Services.RoleService.GetInstalledPermissions()
at Orchard.Roles.Controllers.AdminController.Create()
at lambda_method(Closure , ControllerBase , Object[] )
at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters)
at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass13.<InvokeActionMethodWithFilters>b__10()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass13.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass13.<>c__DisplayClass15.<InvokeActionMethodWithFilters>b__12()
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)

I found a reported issue which did look similar. It was reported against Orchard CMS 1.7 and was marked as resolved. I am using Orchard CMS 1.7.2. Unfortunately, the issue details neither show in which version it was solved nor what the actual root cause was. Since it was closed by Sébastian who’s an Orchard Core developer and was actually born in the same city as I was, I could have contacted him but in-between I found out what the problem was.

Actually my problem was caused by a module I am working on. When disabling the module, it worked fine and when reactivating it, it is broken again.

The problem was in the Permissions.cs file. There were basically two problems. Basically what Orchard does when you click on “Add a role” is to get all features and their permissions. The two problem I had were:

1. The GetPermissions() method did not returned all permissions I had defined and was returning in GetDefaultStereotypes()
2. ReSharper had suggested me to make the setter for the Feature property private since it was not accessed anywhere.

But fixing the first one alone didn’t solve anything. I guess it was necessary to fix it but the root cause of the problem was the private setter for the Feature property. Once I made it public again it worked fine:

public Feature Feature { get; set; }

So the lesson here is that especially when working with such a system as Orchard CMS you should not blindly implement changes in the visibility of properties or methods suggested by ReSharper/Visual Studio. Since properties and methods are rarely directly referenced, your tools will very often miss some dependencies.