I first observed this problem around 48 hours ago, it was definitely still there (in a variety of shells, contexts, etc) just before I posted … and now it’s gone. I have definitely not rebuilt my system or my home-manager in the interim. WTF‽
I spend so much time bumbling around Nix, because I really want … need consistent, reproducible behaviour in order to keep my sanity when dealing with computers. And then stuff like this happens. I … just … whuh? …
[Aside: how often is --show-trace actually helpful? I go through periods of using it, and wasting lots of time trawling through the tons of info it sometimes spews, never getting anything useful out of it, which leads me to forgetting about it for a while. Then the cycle repeats.]
Hmm, yes. I was hacking on packaging something up as an overlay. But I explicitly removed that to make sure that it wasn’t responsible. Maybe I made a mistake and didn’t remove it when I thought I had. Yes, this (unfinished) overlay could well be the cause.