fair enough, but I would go with the new name rather than the old one (I think the new one is clearer).

(sorry, could not keep my bikeshedding comments to my self).

Fair enough! Out of curiousity - are you using Python dev w/ msgspec for something? How did you find this compatibility issue?

I have a project that tries to build the development branch of everything (https://github.com/tacaswell/build_the_world) with the goal of catching these things as early as possible. I then try to work in that environment for my day-to-day development. I was playing with msgspec a while ago so it ended up in my build list.

Really great find, thanks!