Yep! Not every operation you can do on a dict is thread safe but if you find a situation where it isn't it's a bug. https://github.com/python/cpython/issues/11

Yep! Not every operation you can do on a dict is thread safe but if you find a situation where it isn't it's a bug. https://github.com/python/cpython/issues/112075 https://github.com/python/cpython/issues/112075 Google is recommending people not rely on it because it does make dict subclasses not substitutable. It's easy enough to avoid the issue completely so in most cases you might as well do that.