I still have no theory for how this condition was reached despite a lot of time thinking about it and searching for more clues. As far as I can tell, the recent improvements to postmaster's signal and event handling shouldn't be related: the state management and logic was unchanged.
While failing to understand this, I worked[1] on CI log indexing tool with public reports that highlight this sort of thing[2], so I'll be watching out for more evidence. Unfortunately I have no data from before 1 Feb (cfbot previously wasn't interested in the past at all; I'd need to get my hands on the commit IDs for earlier testing but I can't figure out how to get those out of Cirrus or Github -- anyone know how?). FWIW I have a thing I call bfbot for slurping up similar data from the build farm. It's not pretty enough for public consumption, but I do know that this assertion hasn't failed there, except the cases I mentioned earlier, and a load of failures on lorikeet which was completely b0rked until recently. [1] https://xkcd.com/974/ [2] http://cfbot.cputube.org/highlights/assertion-90.html
