404 when viewing "Unpublished" state in the SiteTree history

[gdelavil]

Affected Version

4.7.2 (tested on the Silverstripe demo as well)

Description

When viewing the history of a page and clicking on a state with status Unpublished, the History view hangs (not the whole CMS though, it's still possible to navigate to other pages in the site tree) and the console shows a 404 error. This does not happen for either Saved or Published states.

Unsuccessfully viewing an Unpublished state:

Successfully viewing a Published state:

Successfully viewing Saved states, before and after unpublishing:

I've checked on Slack and I've searched through the existing issues, but this one doesn't seem to have been reported yet.

Steps to Reproduce

1. Create a page
2. Publish it
3. Unpublish
4. Go to History of the page
5. Click on "Unpublished"

A request that looks like https://demo.silverstripe.org/admin/historyviewer/schema/versionForm/7206?RecordVersion=7&RecordClass=Page&RecordID=7206 will return the error {"status":"error","errors":[{"type":"error","code":404}]} (Note that this page will no longer exist, as the Silverstripe demo clears test pages periodically. This issue has been originally found on our code, and we only used the demo page to discard it being a project programming error).

Full request cURL:

curl 'https://demo.silverstripe.org/admin/historyviewer/schema/versionForm/7206?RecordVersion=7&RecordClass=Page&RecordID=7206' \
  -H 'authority: demo.silverstripe.org' \
  -H 'sec-ch-ua: " Not A;Brand";v="99", "Chromium";v="90", "Google Chrome";v="90"' \
  -H 'accept: application/json' \
  -H 'x-formschema-request: auto,schema,state,errors' \
  -H 'sec-ch-ua-mobile: ?0' \
  -H 'user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36' \
  -H 'sec-fetch-site: same-origin' \
  -H 'sec-fetch-mode: cors' \
  -H 'sec-fetch-dest: empty' \
  -H 'referer: https://demo.silverstripe.org/admin/pages/history/show/7206' \
  -H 'accept-language: en-US,en;q=0.9,es;q=0.8,de;q=0.7' \
  -H 'cookie: _ga=GA1.2.122918073.1574992122; intercom-id-c1f8j5ci=75c63a75-85bd-4725-ba27-845bd5e4f2be; __qca=P0-395498613-1610331934619; __cfduid=d726235b256462655c126c233bc127d8d1619999348; _gid=GA1.2.1363369032.1621202636; intercom-session-c1f8j5ci=; PHPSESSID=td2f2rbr7gkn8v1mu6fcr09pi1; _gat=1' \
  --compressed

[NightJar]

This is probably an issue with https://github.com/silverstripe/silverstripe-versioned-admin - I'll transfer the issue there.
Thanks for reporting this so accurately @gdelavil :)

[gdelavil]

Thanks @NightJar ! Credit goes to @ahaleisha for finding it in our project in the first place.