FEATURE: Allow invites redemption with Omniauth providers.

app/controllers/invites_controller.rb

@@ -8,6 +8,7 @@ class InvitesController < ApplicationController
   skip_before_action :preload_json, except: [:show]
   skip_before_action :redirect_to_login_if_required
 
+  before_action :ensure_invites_allowed, only: [:show, :perform_accept_invitation]
   before_action :ensure_new_registrations_allowed, only: [:show, :perform_accept_invitation]
   before_action :ensure_not_logged_in, only: [:show, :perform_accept_invitation]
 
@@ -168,7 +169,8 @@ class InvitesController < ApplicationController
           name: params[:name],
           password: params[:password],
           user_custom_fields: params[:user_custom_fields],
-          ip_address: request.remote_ip
+          ip_address: request.remote_ip,
+          session: session
         }
 
         attrs[:email] =
@@ -284,6 +286,12 @@ class InvitesController < ApplicationController
 
   private
 
+  def ensure_invites_allowed
+    if SiteSetting.enable_discourse_connect || (!SiteSetting.enable_local_logins && Discourse.enabled_auth_providers.count == 0)
+      raise Discourse::NotFound
+    end
+  end
+
   def ensure_new_registrations_allowed
     unless SiteSetting.allow_new_registrations
       flash[:error] = I18n.t('login.new_registrations_disabled')

app/controllers/users/omniauth_callbacks_controller.rb

@@ -119,7 +119,12 @@ class Users::OmniauthCallbacksController < ApplicationController
   end
 
   def invite_required?
-    SiteSetting.invite_only?
+    if SiteSetting.invite_only?
+      path = Discourse.route_for(@origin)
+      return true unless path
+      return true if path[:controller] != "invites" && path[:action] != "show"
+      !Invite.exists?(invite_key: path[:id])
+    end
   end
 
   def user_found(user)

app/controllers/users_controller.rb

@@ -447,8 +447,6 @@ class UsersController < ApplicationController
     elsif current_user&.staff?
       message = if SiteSetting.enable_discourse_connect
         I18n.t("invite.disabled_errors.discourse_connect_enabled")
-      elsif !SiteSetting.enable_local_logins
-        I18n.t("invite.disabled_errors.local_logins_disabled")
       end
 
       render_invite_error(message)