1287527 - Creating an English page that collides with a deleted page results in a 500 error

Status: NEW

Description

[John Whitlock [:jwhitlock]]

What did you do?
================
Create an English page that has the same slug as a deleted page

What happened?
==============
Editing is allowed, but a 500 ISE is returned on saving.  The traceback includes something like:

IntegrityError: (1062, "Duplicate entry 'Web/CSS/-webkit-box-orient-en-US' for key 'wiki_document_slug_68e6ba482859eef0_uniq'")

What should have happened?
==========================
At a minimum, a form error should be returned, informing the user that there is a collision with a deleted document, and to email to site administrators to handle the deleted document. Site administrators could then restore the deleted document, making it available for editing, or purge it, allowing a new document to be created.

A improvement would be detecting if someone has access to purge or restore a document, and giving them links to take those actions.

A further improvement would be a async request to determine if there is a collision with a deleted page, and warning the user before they select save.  This is probably the solution desired by bug 1000320

Is there anything else we should know?
======================================
A recent occurrence was tracked in Sentry:

https://sentry.prod.mozaws.net/operations/mdn-prod/issues/241215/