error page from "OrchardCore.Diagnostics" module isn't presented when [ValidateAntiForgeryToken] attribute is used and validation failed

[lampersky]

Describe the bug

Sometimes, when my "orchantiforgery_" cookie expires, and when login page is still opened in browser, I can't log in, because of AntiforgeryValidationException which is expected behavior, but instead of seeing error page from 'OrchardCore.Diagnostics' I see default one.

You can reproduce the issue by removing "orchantiforgery_" cookie, or by manipulating with html code.

Steps to reproduce the behavior:

1. Make sure 'OrchardCore.Diagnostics' module is enabled,
2. Go to 'https://try.orchardcore.net/Login',
3. Inspect page and change value of '__RequestVerificationToken' input,
4. Click on 'Log in',
5. See default 400 error page.
   

Expected behavior

This error page should be presented to the user:

[sebastienros]

Maybe a middleware order, specific to antiforgery token.

[lampersky]

this issue is related to this change

[hishamco]

@deanmarcussen seems this broken after #3993

[sebastienros]

@lampersky any suggestion on how to fix it? or if the order is the issue?

[lampersky]

@sebastienros when you are applying filter globally it means that every controller will be affected, even our DiagnosticsController and that's why we are observing issue with app.UseStatusCodePagesWithReExecute("/Error/{0}")

The simplest way to fix this issue is just by adding [IgnoreAntiforgeryToken] attribute to DiagnosticsController.
This will prevent antiforgery token validation for re executed requests.

I've just prepared PR