RuntimeError in Devise::InvitationsController#create, Could not find a valid mapping for nil

Question

I am using devise_invitable gem in my rails 5 application. Every time after submitting the "Send an Invitation" button, I get the error RuntimeError in Devise::InvitationsController#create, Could not find a valid mapping for nil

Here is the code of application_controller.rb file:

class ApplicationController < ActionController::Base
    protect_from_forgery with: :exception
    before_action :configure_permitted_parameters, if: :devise_controller?

    def authenticate_inviter!
        unless current_user.role=='Manager'
            if current_user.role == "Developer"
                redirect_to root_path, :alert => "Access Denied! Only Manager Can Add New Developer"
            end
            super
        end
    end
    protected
    def configure_permitted_parameters
        added_attrs = [ :email, :password, :password_confirmation ]
        devise_parameter_sanitizer.permit :sign_up, keys: added_attrs
        devise_parameter_sanitizer.permit :account_update, keys: added_attrs
        devise_parameter_sanitizer.permit :accept_invitation, keys: [:email]
    end
end

Here is the Code of User.rb:

class User < ApplicationRecord
    include DeviseInvitable::Inviter
    devise :invitable, :database_authenticatable, :registerable,
     :recoverable, :rememberable, :validatable
end

Here is Route.rb

Rails.application.routes.draw do
    devise_for :users
    root 'dashboard#index'
end

Here is all routes:

                       Prefix Verb   URI Pattern                                                                              Controller#Action
         new_user_session GET    /users/sign_in(.:format)                                                                 devise/sessions#new
             user_session POST   /users/sign_in(.:format)                                                                 devise/sessions#create
     destroy_user_session DELETE /users/sign_out(.:format)                                                                devise/sessions#destroy
        new_user_password GET    /users/password/new(.:format)                                                            devise/passwords#new
       edit_user_password GET    /users/password/edit(.:format)                                                           devise/passwords#edit
            user_password PATCH  /users/password(.:format)                                                                devise/passwords#update
                          PUT    /users/password(.:format)                                                                devise/passwords#update
                          POST   /users/password(.:format)                                                                devise/passwords#create
 cancel_user_registration GET    /users/cancel(.:format)                                                                  devise_invitable/registrations#cancel
    new_user_registration GET    /users/sign_up(.:format)                                                                 devise_invitable/registrations#new
   edit_user_registration GET    /users/edit(.:format)                                                                    devise_invitable/registrations#edit
        user_registration PATCH  /users(.:format)                                                                         devise_invitable/registrations#update
                          PUT    /users(.:format)                                                                         devise_invitable/registrations#update
                          DELETE /users(.:format)                                                                         devise_invitable/registrations#destroy
                          POST   /users(.:format)                                                                         devise_invitable/registrations#create
   accept_user_invitation GET    /users/invitation/accept(.:format)                                                       devise/invitations#edit
   remove_user_invitation GET    /users/invitation/remove(.:format)                                                       devise/invitations#destroy
      new_user_invitation GET    /users/invitation/new(.:format)                                                          devise/invitations#new
          user_invitation PATCH  /users/invitation(.:format)                                                              devise/invitations#update
                          PUT    /users/invitation(.:format)                                                              devise/invitations#update
                          POST   /users/invitation(.:format)                                                              devise/invitations#create
                     root GET    /                                                                                        dashboard#index
       rails_service_blob GET    /rails/active_storage/blobs/:signed_id/*filename(.:format)                               active_storage/blobs#show
rails_blob_representation GET    /rails/active_storage/representations/:signed_blob_id/:variation_key/*filename(.:format) active_storage/representations#show
       rails_disk_service GET    /rails/active_storage/disk/:encoded_key/*filename(.:format)                              active_storage/disk#show
update_rails_disk_service PUT    /rails/active_storage/disk/:encoded_token(.:format)                                      active_storage/disk#update
     rails_direct_uploads POST   /rails/active_storage/direct_uploads(.:format)                                           active_storage/direct_uploads#create

• I haven't created any custom invitations controller.

• I just run the following to setup and configure devise_invitable

  gem 'devise_invitable'

  bundle install

  rails generate devise_invitable:install

  rails generate devise_invitable User

  rails db:migrate

  rails generate devise_invitable:views

  restart the rails server

Here is the picture of the complete error: see the picture of the complete error

How can I get rid of this problem. Please help me

Answer 1

Finally I have solved this issue by the help of Scambra

I have just changed the logic of my Application Controller

From:

def authenticate_inviter!
    unless current_user.role=='Manager'
        if current_user.role == "Developer"
            redirect_to root_path, :alert => "Access Denied! Only Manager Can Add New Developer"
        end
        super
    end
end

To:

def authenticate_inviter!
      if current_user.role == "Developer"
          redirect_to root_path, :alert => "Access Denied! Only Manager Can Add New Developer"
      end
      super
end