Today on itwiki I noticed a serious problem: as any other wikis, we have several filters set to throttle and then disallow the edit (or block the user) after a fixed amount of edits. By chance, I noticed that one of these filters isn't working at all: see filter settings and its AbuseLog, compared to the amount of edits of the last user hitting it (requires privileges). The rate limiter isn't taken into account at all, thus always disallowing the first edit. The last change to that filter is from May, and the new version of MediaWiki (1.33.0-wmf.6), which solves throttle-related problems, still hasn't got on itwiki. Since that filter has nothing special and the problem doesn't directly depends on a MediaWiki update, this means that potentially every filter using throttle in WMF prod is misbehaving and ignoring throttle.
I can surely say that the problem started yesterday between 16:43-16:45 UTC (basing on user contributions and filter hits); so, in order to move on, we basically need two things:
- Understand what happened yesterday at that time
- A logstash grep for basically every message passed to logger->debug() inside AbuseFilter::isThrottled(), for itwiki and for the time period 16:30 UTC - 9:30 UTC (if there are too many entries we'll see how to refine the search)
Needless to say, I already disabled the offending filter on itwiki, but that wouldn't help much in the case of a "global" bug.