Looks like https://en.wikipedia.org/wiki/Template:TFA_title/October_19,_2016 is empty today, so the TFA endpoint is returning a 404.
Unfortunately, this error is being propagated and the aggregated feed endpoint for enwiki is currently returning an error response; see T148638: Missing TFA takes out all feed content. But, it's not causing the app to crash.
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Resolved | • Mholloway | T148638 Missing TFA takes out all feed content | |||
| Resolved | • Mholloway | T148636 Enwiki featured article for 10/19 not found |
I left a note on https://en.wikipedia.org/wiki/Talk:Main_Page to alert someone to populate the main page title for this day. I don't have the rights to do it myself, so I hope someone gets around to it quickly.
Interestingly, the tfa section is currently still omitted from the aggregated endpoint response, it's just not returning an error anymore.
It looks like the root of the issue was that AnomieBOT II (operated by our very own @Anomie) produces the TFA Title templates, and it hiccuped on today's featured article title because it's wrapped in a strangely-formatted template within the Main Page blurb.
AnomieBOT looks for the following patterns to detect the featured article from the blurb. Optional whitespace is generally allowed where it doesn't break the wikitext.
In this case, however, the blurb has the title as '''''{{lang|de|[[Komm, du süße Todesstunde, BWV 161|Komm, du süße Todesstunde]]}}'''''. It would have been recognized by the bot had it been {{lang|de|'''''[[Komm, du süße Todesstunde, BWV 161|Komm, du süße Todesstunde]]'''''}} or '''''[[Komm, du süße Todesstunde, BWV 161|{{lang|de|Komm, du süße Todesstunde}}]]''''' or a few other variations instead. If there are other patterns that need to be recognized I can add them; it would probably be best to post on the bot's talk page about that.
Closed since this incident is resolved and created T148680: Investigate FeaturedFeeds for further exploratory work.