How to handle incorrect ROOT_URL for gitea.com

[wxiaoguang]

After the PR (background #19345)

• Show messages for users if the ROOT_URL is wrong, show JavaScript errors #18971

Now if users visit www.gitea.com, they will see the prompt.

I think the prompt is correct at the moment.

A real case: if users log into www.gitea.com, then many URLs are pointing to gitea.com, then if they try to visit it, they are still not logged-in on gitea.com because the cookie is not shared between these two domains.

This problem becomes more serious because some forms and ajax requests are using absolute URL to gitea.com, users may lose their work if they try to submit request to gitea.com from www.gitea.com.

And that's one of the reasons why some users complain that their work are lost, see screenshot 2, the URL in form is absolute.

Then the question is: how to continue? IMO the proper way is to make www.gitea.com redirect users to gitea.com at the moment.

Screenshot 1, incorrect ROOT_URL

Screenshot 2, the absolute URL in form

[lunny]

We always need to redirect www.gitea.com to gitea.com