Bad typing for requests.cookies.RequestsCookieJar

RequestsCookieJar is typed as a subtype of both http.CookieJar and MutableMapping[str, str]:

https://github.com/python/typeshed/blob/6ee36bacecd24fca98d080a6965821e7e2d9e590/stubs/requests/requests/cookies.pyi#L38

including a comment ignoring the type error. This is simply wrong; RequestsCookieJar is not a MutableMapping because the __iter__ fn differs.

This causes real problems:

import requests.cookies
import typing

cookiejar = requests.cookies.RequestsCookieJar()
cookiejar["a"] = "b"

print("outside func")
for cookie in cookiejar:
    typing.reveal_type(cookie) # type is Cookie at typecheck and runtime
    print(f"{type(cookie)=}")

def in_func(not_a_cookiejar:typing.Iterable[str]):
    print("in_func")
    for maybe_cookie in not_a_cookiejar:
        typing.reveal_type(maybe_cookie) # type is str at typecheck
        print(f"{type(maybe_cookie)=}") # type is Cookie at runtime

in_func(cookiejar)

pyright 1.1.407 says:

information: Type of "cookie" is "Cookie"
information: Type of "maybe_cookie" is "str"

mypy 1.19.1 says:

bad-types.py:9: note: Revealed type is "http.cookiejar.Cookie"
bad-types.py:15: note: Revealed type is "builtins.str"

Start in stubs/requests/requests/cookies.pyi at the RequestsCookieJar declaration around line 38, then compare its iter behavior with the MutableMapping[str, str] annotation. Run the provided pyright and mypy reproduction to verify that iteration is typed and behaves as Cookie values. Done means the stub no longer gives callers an incorrect iterable element type.