Don't show Visual diff switcher for diff of suppressed revisions
Open, LowPublicBUG REPORT
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Authored By

	dom_walden
	May 31 2023, 8:02 AM

Description

What is the problem?

When viewing a diff where one of the revisions is suppressed, if you try to switch to the "Visual" diff you see the error:

Invalid response from server

The specified title ($1) does not exist

If Visual diff does not support suppressed revisions, we should probably not show the switcher.

Steps to reproduce problem

Observed behavior: You see an error.

Environment

Wiki(s): https://en.wikipedia.beta.wmflabs.org MediaWiki 1.41.0-alpha (5720e51) 07:27, 31 May 2023. VisualEditor 0.1.2 (4b661a1) 06:21, 31 May 2023.

Screenshots

suppressed_revision_diff.png (701×1 px, 88 KB)

Related Objects

Mentioned In: T346213: Diff content sometimes not displayed correctly when switching to Visual diff fails
Mentioned Here: T171937: Historical visual diff broken for revision deletions
rEVED4b661a1fcda3: Localisation updates from https://translatewiki.net.
rMW5720e517aa50: Merge "Prompt temporary users without upload permissions to log in"

Event Timeline

dom_walden created this task.May 31 2023, 8:02 AM

Restricted Application added a subscriber: Aklapper. · View Herald TranscriptMay 31 2023, 8:02 AM

Maintenance_bot added a project: VisualEditor.May 31 2023, 8:29 AM

It looks like DifferenceEngine.php does not output anything semantic when it is unable to show a revision, so the VE integration doesn't really have anything to look for, other than a lack of diff lines.

Setting to low priority as this is a rare edge case, and the suggested improvement is just a better error message.

If anyone wants to submit a patch, the relevant files are ve.init.mw.DiffPage.init.js in VE and DifferenceEngine.php in core.

Previously: T171937#6857898

ppelberg moved this task from To Triage to Triaged on the VisualEditor board.Jun 29 2023, 3:49 PM

MusikAnimal mentioned this in T346213: Diff content sometimes not displayed correctly when switching to Visual diff fails.Sep 19 2023, 7:46 PM

This is still a problem, although a few things have changed since the initial report:

The switcher is not displayed, but if the previous diff you viewed was in visual mode, then the visual diff mode is still active and causes the error to be shown
The error message now is rest-permission-denied-revision / missing-revision-permission, and it's shown with broken formatting. (It's also the wrong error, it shows even when the viewing user does not have the permission to view the diff.)

User doesn't have access to the requested revision (The revision #483920 belongs to a deleted page. You can [https://en.wikipedia.beta.wmflabs.org/w/index.php?title=Special:Undelete&target=Conflict-title-0.25968288104487747-Iñtërnâtiônàlizætiøn×tamp=20210323161909&diff=prev view it]; details can be found in the [https://en.wikipedia.beta.wmflabs.org/w/index.php?title=Special:Log/delete&page=Conflict-title-0.25968288104487747-Iñtërnâtiônàlizætiøn deletion log].).

Reported at https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#RevDel_Error_Message.

	F57746017: image.png
	Mon, Nov 25, 5:02 PM

Don't show Visual diff switcher for diff of suppressed revisionsOpen, LowPublicBUG REPORTActions