This is ugly.

The core problem here is that SpecialMobileContributions doesn't extend core's ContribsPager but re-implements it. The relevant code that "fixes" this bug in core is:

/*
 * There may be more than just revision rows. To make sure that we'll only be processing
 * revisions here, let's _try_ to build a revision out of our row (without displaying
 * notices though) and then trying to grab data from the built object. If we succeed,
 * we're definitely dealing with revision data and we may proceed, if not, we'll leave it
 * to extensions to subscribe to the hook to parse the row.
 */
Wikimedia\suppressWarnings();
try {
	$rev = new Revision( $row );
	$validRevision = (bool)$rev->getId();
} catch ( Exception $e ) {
	$validRevision = false;
}
Wikimedia\restoreWarnings();

This code is… not good. Copying into MF seems unclean.

Change 446748 had a related patch set uploaded (by Jforrester; owner: Jforrester):
[mediawiki/extensions/MobileFrontend@master] SpecialMobileContributions: Don't show fake revs, like page move "to" entries

https://gerrit.wikimedia.org/r/446748

Thanks for investigating and submitting the intermediate fix, @Jdforrester-WMF. Once the error's dealt with, Readers Web should look at using ContribsPager rather than duplicating it.

In T199066#4437251, @phuedx wrote:

Thanks for investigating and submitting the intermediate fix, @Jdforrester-WMF. Once the error's dealt with, Readers Web should look at using ContribsPager rather than duplicating it.

Totally, though ContribsPager's code isn't great either. :-(

Change 447612 had a related patch set uploaded (by Jdlrobson; owner: Jdlrobson):
[mediawiki/extensions/MobileFrontend@master] Special:MobileContributions should use ContribsPager

https://gerrit.wikimedia.org/r/447612

Since this has happened before in a different form, I'd like to use this opportunity to entertain using the Pager here given the low amount of errors rather than piling on more hacks. What do you think?

I've written https://gerrit.wikimedia.org/r/#/c/mediawiki/extensions/MobileFrontend/+/447612 but am not sure how to replicate the error right now to check if that alone solves this? Does it?

@Krinkle @Jdforrester-WMF any ideas on how to replicate this locally?

I had a way to reproduce it, but unable to at the moment due to T200269.

I haven't been able to re-create the kind of contribution history that we see on en.wikipedia.org. It might be that the "move" action creates revisions a different way now than it used to in 2010. Or it might be that what we see on enwiki is the result of multiple actions (e.g. the page later being renamed again, or being deleted/re-created or some such).

So aside from the example in the task description that we can test, I'm not sure how to test it on another wiki or locally.

In T199066#4450307, @Krinkle wrote:

I haven't been able to re-create the kind of contribution history that we see on en.wikipedia.org. It might be that the "move" action creates revisions a different way now than it used to in 2010.

Correct; this is a bug affecting how move used to work and how some extensions still work, I believe.

So aside from the example in the task description that we can test, I'm not sure how to test it on another wiki or locally.

I manually duped the revision DB rows from production to my local wiki for testing (which is cheating, but…).

Have also not been able to reproduce. If we take the approach in https://gerrit.wikimedia.org/r/#/c/mediawiki/extensions/MobileFrontend/+/447612 can we simply call formatRow ?

@Jdforrester-WMF are you able to test/work with the patch in https://gerrit.wikimedia.org/r/#/c/mediawiki/extensions/MobileFrontend/+/447612 since you can recreate this issue?

Change 448001 had a related patch set uploaded (by Jdlrobson; owner: Jdlrobson):
[mediawiki/core@master] Refactor revision check out of formatRow

https://gerrit.wikimedia.org/r/448001

Change 446748 abandoned by Jforrester:
SpecialMobileContributions: Don't show fake revs, like page move "to" entries

Reason:
Better to go with Jon's proper fix.

https://gerrit.wikimedia.org/r/446748

Added Technical-Debt as this patches FIXME: Make Special:MobileContributions use ContribsPager ASAP. that was added two years ago. Also moving to doing column to reflect that fact that we're currently working on this task.

https://gerrit.wikimedia.org/r/448001 needs review to get this started!

We discussed this in standup briefly and estimated it as a 5. Due to the larger estimate and the new approach, we decided to move back to upcoming for the time being.

Change 448001 merged by jenkins-bot:
[mediawiki/core@master] ContribsPager: Factor revision check out of formatRow

https://gerrit.wikimedia.org/r/448001

Change 446748 restored by Jdlrobson:
SpecialMobileContributions: Don't show fake revs, like page move "to" entries

https://gerrit.wikimedia.org/r/446748

We have two approaches to this:

• https://gerrit.wikimedia.org/r/446748 (short term solution with less risk)
• https://gerrit.wikimedia.org/r/447612 (higher risk)

Sorry, meant to put this in <= .19 instead.

Change 446748 abandoned by Jdlrobson:
SpecialMobileContributions: Don't show fake revs, like page move "to" entries

Reason:
From Timo's comments, I think we prefer the ContribsPager approach in https://gerrit.wikimedia.org/r/#/c/mediawiki/extensions/MobileFrontend/ /446748/ ?

Please restore if wrong.

https://gerrit.wikimedia.org/r/446748

Change 447612 merged by jenkins-bot:
[mediawiki/extensions/MobileFrontend@master] Special:MobileContributions should use ContribsPager

https://gerrit.wikimedia.org/r/447612

☝️ AIUI this task led to T208469: Spike in PHP warnings from User.php; triggered from MobileFrontend's new use of ContribsPager with a User object instead of a string, which was blocking the rollout of the -wmf.2 branch.

Correcto

This has been live in production for about a month now so you can QA in production...

No more badtitle (or production log errors):

Tested, looks correct.