@Jdlrobson: Could you add the frequency at which this warning is triggered? It'd be useful for prioritisation.

2 per hour on a couple of hours. Nothing too serious it seems. I'll add it to the description.

The offending source fo reference.

/**
 * Create a getter function for the patrol link in Mobile Diff.
 * FIXME: This shouldn't be needed, but markPatrolledLink is protected in DifferenceEngine
 * @return String
 */
public function getPatrolledLink() {
	$linkInfo = $this->getMarkPatrolledLinkInfo();
	if ( $linkInfo ) {
		$this->getOutput()->addModules( 'mobile.patrol.ajax' );
		$linkInfo = Html::linkButton(
			$this->msg( 'markaspatrolleddiff' )->escaped(),
			[
				'href' => $this->mNewPage->getLocalUrl( [
					'action' => 'markpatrolled',
					'rcid' => $linkInfo['rcid'],
					'token' => $linkInfo['token'],
				] ),
			]
		);
	}
	return $linkInfo;
}

This was broken by T130946 and I6be2c07824c17b165e068fc4ac36ab192e12bc9d which removed the token from this method which is why it reports as unset.

Good catch @Jdlrobson

These errors also occur more than T151838 which is high so we may want to make this high as well.

In T151837#2836720, @Jdlrobson wrote:

These errors also occur more than T151838 which is high so we may want to make this high as well.

AFAICT T151838: [4 hours] Warning: Invalid state error in MobileFormatter was made high priority as it'd been moved into the sprint (without discussion). You might want to bring this issue to @ovasileva's attention.

@Jdlrobson - normal sounds good. And yes, T151838: [4 hours] Warning: Invalid state error in MobileFormatter was made high since it was already in the sprint.

Change 334416 had a related patch set uploaded (by Jdlrobson):
Token is not always set in diff

https://gerrit.wikimedia.org/r/334416

(Saw this issue on a diff page when logged in)
http://localhost:8888/w/index.php?title=Special:MobileDiff/1889

@Jdlrobson: I'm going to need a little more information in order to reproduce the warning. I can't get the lines in question to execute, i.e. I can't get a patrol link to be generated. I can see that DifferenceEngine#getMarkPatrolledLinkInfo no longer returns a dictionary containing the 'token' key, which is why the warning is being triggered and I can also tell that your change fixes the issue but, if possible, I'd like to see it first hand before I +2.

I seem to be able to replicate this when I visit a diff page that belongs to a user with no groups.
So maybe this might replicate it for you:

1. Create new account
2. Edit some pages as that user
3. Logout
4. Visit diffs of those edits

Note permissions and warnings in these two examples:

👍 It was the "Create a new account" step that I'd skipped. The user I was editing as was a sysop and so their edits were auto-patrolled.

Change 334416 merged by jenkins-bot:
Token is not always set in diff

https://gerrit.wikimedia.org/r/334416

URL for testing

Change 341930 had a related patch set uploaded (by Krinkle):
[mediawiki/extensions/MobileFrontend] diff: $linkInfo is not an array of query parameters

https://gerrit.wikimedia.org/r/341930

Change 341930 merged by jenkins-bot:
[mediawiki/extensions/MobileFrontend] diff: $linkInfo is not an array of query parameters

https://gerrit.wikimedia.org/r/341930

^ Per T151837#3088806 and the notice hasn't reappeared since rEMFRe595315f7bdf: diff: $linkInfo is not an array of query parameters was merged.

In T151837#2836711, @Jdlrobson wrote:

I'm bumping priority as I worry that this will drop of our radar and I suspect this prevents patrollers from patrolling on mobile (hence why we see so few events - not everyone is a patroller)

Have we seen an increase in the number of "patroller events" – I'm not sure exactly what you mean here – since the error was fixed?

Huh? This comment is from November way before we fixed it.

I know it's an old comment. I was just wonder if we've seen an increase in the number of the events that you mentioned. Is there any way to check?

I didn't write this so well. The events I was referring to were notices. I was simply pointing out that not all users are patrollers so this would only impact any logged in user with the patrol right viewing the diff page. I don't believe we track patrolling in any way.

Ah!