Make frame.f_locals.copy() return a snapshot dict of f_locals #118921
Description
Feature or enhancement
Proposal:
Per PEP 667, frame.f_locals is now a write-through proxy (FrameLocalsProxy) for underlying fast local variables. In the beginning we did not implement the copy() method because we think dict(frame.f_locals) is a more explicit way to achieve the snapshot. However, there are existing code that's using frame.f_locals.copy() to take a snapshot. Moreover, types.MappingProxyType({}).copy() returns the copy of the underlying mapping so it's not unprecedented for a proxy.copy() to return a dict.
Thus, we should implement copy() method for FrameLocalsProxy and make it return a dict of snapshot of the current local variables.
Has this already been discussed elsewhere?
I have already discussed this feature proposal on Discourse
Links to previous discussion of this feature:
https://discuss.python.org/t/pep-667-consistent-views-of-namespaces/46631/26