Split from T335389

(3) Undo from View history doesn't work? Rollback works as expected.

Steps:

1. As an Autoconfirmed user, go to a function page and make some minor edits, e.g. change Name label or Add labels in another language. Publish edits.
2. Go to "View history" and click on undo - the page will open in editing mode; the url indicates which revision the 'undo' action is going to be applied, e.g. https://wikifunctions.beta.wmflabs.org/w/index.php?title=Z10147&action=edit&undoafter=4410&undo=4411.

However, the page

• doesn't provide diff view
• Publish button is inactive

At this point, users can only manually revert their recent edits ("View history" adds the 'Manual revert' tag).

Note:

• click on any revision in "View history" and the most recent revision will be displayed (e.g. title=Z10147&oldid=4380 and ?title=Z10147&oldid=4411