The featured article updates on Main Page are somewhat of a hack on the main site. Basically, all of those featured articles / image of the day etc transclusions are templating the transclusion by date. However, MediaWiki's change propagation system is oblivious to such date-dependent templating, and won't update the page when the date (and thus the translusion) changes. It *does* react to changes in currently-transcluded content or the page itself, and those events are driving RESTBase updates. Since those edits aren't happening all the time, the updates aren't reliably happening whenever the date changes.

To work around this limitation for the desktop site, people have set up a special-case cron job for Main Page, which calls action=purge every 24 hours. To make those hacks work on RESTBase content as well, we could consider hooking into action=purge as well.

@GWicke. Do you have a separate ticket for this or do you want to just use this one? This issue is blocking us from moving MCS to production.

Let's use this one as the Android app is the only one currently that is really impacted by this.

Change 270876 had a related patch set uploaded (by Ppchelko):
Hooking into action=purge api call to detect changes with transclusions by date.

https://gerrit.wikimedia.org/r/270876

I went ahead and implemented a very simple change in RestBaseUpdateJobs extension as I've been in vagrant territory anyway today.

However, when we switch from the RestBaseUpdateJobs extension to change propagation, we would not be able to do the same hack, so we also need to change the EventBus extension to emit an event on purge. This might be either a special page_purged event, or a general resource_changed event that is being discussed now. However, it's not super-logical that a purge leads to a resource_changed event..

Change 270876 merged by Mobrovac:
Hooking into action=purge api call to detect changes with transclusions by date.

https://gerrit.wikimedia.org/r/270876

Thank you, @Pchelolo!

With a bit of luck this *might* be scheduled to go out with the next train deploy, which would put it on the cluster by Thursday.

In T126979#2032611, @GWicke wrote:

This is scheduled to go out with the next train deploy. If the train keeps moving to plan, this *might* be live by Thursday.

It will indeed. The patch made it into the wmf.14 branch, which should be on all wikis by Thursday.

I got the current main page content in the dev build today. :) I'll look again on Monday for good measure and then I think we can call it a win.

Still good. :) Should I close this task, or leave it open pending the EventBus change that @Pchelolo mentioned?

@Mholloway Let's wait till https://gerrit.wikimedia.org/r/270876 gets deployed and then verify the fix actually works in production.