It is a change request to clean up message from the time before links in the summary. I even believe I wrote something similar in Bugzilla… ;)

The title can be changed if anyone has a serious problem with it.

I noticed that wikibase-entity-summary-restore has a similar issue in which the revision number isn't a link. It also lacks the link to the revision author's talk page. This is what it is currently:

Restore revision $3 by [[Special:Contributions/$4|{{GENDER:$4|$4}}]]

Would it make sense to make wikibase-entity-summary-restore consistent with wikibase-entity-summary-undo? I didn't find another ticket covering this.

Change #1080752 had a related patch set uploaded (by Audrey Penven; author: Audrey Penven):

[mediawiki/extensions/Wikibase@master] Add link to revision in undo + restore summaries

https://gerrit.wikimedia.org/r/1080752

IMHO:

• Let’s add the user talk link to the restore message. The current versions of the restore and undo messages were both introduced in the same change (by @matej_suchanek – ping, in case he wants to comment ^^), with the user talk link for undo but no link for restore. The undo message was meant to replace a previous message from MediaWiki core, which had (and still has) the talk page link, while the restore message replaced an earlier message in Wikibase (introduced in 2012) which didn’t have the talk page link, so I think that’s why the messages are the way they are – but the lack of a link in the old Wikibase restore message was probably not intentional.
• The link in the undo message should link to Special:Diff, not Special:Redirect/revision, since the edit is about undoing that diff, not about the rest of the contents as they were in that old revision.
• The link in the restore message, on the other hand, should link to Special:Redirect/revision (or Special:Permalink), since the edit is about restoring the full contents of that revision.

In T194402#10237108, @Lucas_Werkmeister_WMDE wrote:

the restore message replaced an earlier message in Wikibase (introduced in 2012) which didn’t have the talk page link, so I think that’s why the messages are the way they are

Other than yours, I have no explanation for it.

• The link in the undo message should link to Special:Diff, not Special:Redirect/revision, since the edit is about undoing that diff, not about the rest of the contents as they were in that old revision.
• The link in the restore message, on the other hand, should link to Special:Redirect/revision (or Special:Permalink), since the edit is about restoring the full contents of that revision.

+1

Change #1080752 merged by jenkins-bot:

[mediawiki/extensions/Wikibase@master] Add link to revision in undo + restore summaries

https://gerrit.wikimedia.org/r/1080752

Given that we want to save database space, why is the word revision needed here?

Why not just "Undo [[Special:Redirect/revision/$3|$3]] by [[Special:Contributions/$4|{{GENDER:$4|$4}}]] ([[User talk:$4|talk]])"?

The transformation happens on-the-fly, it has no impact on the database storage. I wonder if "Undo 123456789 ..." can be understood by everyone.