CookieDefaultPolicy.set_port_ok and return_ok_port func does not work for IPv6 addresses

Bug description:

POC:

import urllib.request
from http.cookiejar import CookieJar, DefaultCookiePolicy
class FakeResponse:
    def __init__(self, headers=[], url=None):
        """
        headers: list of RFC822-style 'Key: value' strings
        """
        import email
        self._headers = email.message_from_string("\n".join(headers))
        self._url = url
    def info(self): return self._headers
pol = DefaultCookiePolicy(
            rfc2965=True, blocked_domains=[])
c = CookieJar(policy=pol)
c.clear()
headers = ["Set-Cookie: CUSTOMER=WILE_E_COYOTE; path=/; port=1234"]
req = urllib.request.Request("http://127.0.0.1:1234")
res = FakeResponse(headers, "http://127.0.0.1:1234")
print(pol.set_ok_port(c.make_cookies(res, req)[0], req))
print(pol.return_ok_port(c.make_cookies(res, req)[0], req))
# output: True, True

req_IPv6 = urllib.request.Request("http://[::1]:1234")
res_IPv6 = FakeResponse(headers, "http://[::1]:1234")
print(pol.set_ok_port(c.make_cookies(res_IPv6, req_IPv6)[0], req_IPv6))
print(pol.return_ok_port(c.make_cookies(res_IPv6, req_IPv6)[0], req_IPv6))
# output: False, False

Well, port 1234 is the correct port. Then why request with host [::1] always return False?
Let's dive in to the function:

    def set_ok_port(self, cookie, request):
        if cookie.port_specified:
            req_port = request_port(request)
            if req_port is None:
                req_port = "80"
            else:
                req_port = str(req_port)
            for p in cookie.port.split(","):
                try:
                    int(p)
                except ValueError:
                    _debug("   bad port %s (not numeric)", p)
                    return False
                if p == req_port:
                    break
            else:
                _debug("   request port (%s) not found in %s",
                       req_port, cookie.port)
                return False
        return True

So, the req_port is set by func request_port(), lets check it:

def request_port(request):
    host = request.host
    i = host.find(':')
    if i >= 0:
        port = host[i+1:]
        try:
            int(port)
        except ValueError:
            _debug("nonnumeric port: '%s'", port)
            return None
    else:
        port = DEFAULT_HTTP_PORT
    return port

So that's where thing goes wrong. if the input of request_port is an IPv6 addr like [::1]. It will actually always raises a ValueError and return None caz it tries to int(":1]:1234") instead of int("1234") and the port will be forced to 80. Which not equals to 1234, and returns False.

It is totally not a rocket science to solve this, but I need the helper functions of IPv6 in #135768 to land before the PR. I've already completed the PR based on the helper functions,

Same thing works for return_ok_port

cc @picnixz here if you have more advice, thanks!

CPython versions tested on:

3.14

Operating systems tested on:

Windows

Linked PRs

• gh-136076

Start with request_port(), set_ok_port(), and return_ok_port(), then run the IPv4 and IPv6 reproducer in the issue. Check the related IPv6 helper work in gh-135768 and the linked PR gh-136076; the issue is done when port 1234 is accepted for both address forms without regressing the IPv4 behavior.