Add a message to the 404 page to indicate it may be a permission issue

Zendesk: https://gitlab.zendesk.com/agent/tickets/15943

We display a 404 page when users don't have permission to a project to avoid leaking information about projects/groups. It could be advantageous to add an ambiguous message to the 404 page saying 'it either doesn't exist or you don't have permission to view the resource'. This would be similar to what we do for password reset: 'If your account exists in our system, you will receive a message'. We are descriptive but avoid disclosing whether the account exists.

cc/ @JobV @DouweM What do you think?

@dblessing Good idea

mentioned in merge request gitlab-foss!4174 (closed)

Reassigned to @lbennett

Assignee removed

any news on this ?

@lbennett Can we open this for a Community Contribution in GitLab FOSS to add?

We can discuss on the content of the display message here beforehand, but it would make a nice first contribution for someone Thanks!

added feature proposal in GitLab FOSS ~1208338 labels

@markglenfletcher Sounds like a great idea. :)

added Community Contribution in GitLab FOSS label

Looks like we mean Accepting Merge Requests in GitLab FOSS? Since I don't see a contribution yet

Thanks.

What should we use for this ambiguous message? Along the same lines of the password reset email we could use:

"The resource that you are attempting to access does not exist or you don't have the necessary permissions to view it"

@markglenfletcher is this how it should be?

@brancho Yes. Let's go with that text. Would you like to create a Merge Request to add it?

That probably won't make any difference to me though. Since I already know what 404 means, so I would only read the heading but only because the words are large and I would see it anyway. Yet, I would still assume it's missing, not because I might not able to read it.

I suggest we also change the heading. Maybe something like:

404

This page could not be found or you don't have the permission.

mentioned in merge request gitlab-foss!13982 (merged)

@godfat I changed the title, added the message and created a merge request @markglenfletcher

assigned to @brancho

changed milestone to %10.0 in gitlab-foss

moved from gitlab-foss#17467 (moved)