Oh! I only realized now that my patch for rspec-mocks was merged 5 years ago: https://github.com/rspec/rspec-mocks/pull/1218

It's still in 4.0 beta though, no stable release yet 😬 https://github.com/rspec/rspec/blob/v4.0.0.beta1/rspec-mocks/Changelog.md#400beta1--2026-02-18

I understand it's considered a breaking change because it's fixing a "bug" that does change the behavior.

I am still pretty proud that most of the bugs I found in rspec mocks could not be reproduced in muack: https://github.com/godfat/muack

It's also pretty small, too! However it's fully feature complete.