Handle response with multiple same name cookies

Closes aio-libs#4486

aiohttp/client_reqrep.py

@@ -7,7 +7,7 @@
 import traceback
 import warnings
 from hashlib import md5, sha1, sha256
-from http.cookies import CookieError, Morsel, SimpleCookie
+from http.cookies import BaseCookie, CookieError, Morsel, SimpleCookie
 from types import MappingProxyType, TracebackType
 from typing import (
     TYPE_CHECKING,
@@ -736,7 +736,7 @@ def __init__(
         assert isinstance(url, URL)
 
         self.method = method
-        self.cookies = SimpleCookie()  # type: SimpleCookie[str]
+        self.cookies = []  # type: List[Tuple[str, BaseCookie[str]]]
 
         self._real_url = url
         self._url = url.with_fragment(None)
@@ -922,7 +922,10 @@ async def start(self, connection: "Connection") -> "ClientResponse":
         # cookies
         for hdr in self.headers.getall(hdrs.SET_COOKIE, ()):
             try:
-                self.cookies.load(hdr)
+                new_cookie = SimpleCookie()
+                new_cookie.load(hdr)
+                new_cookie_list = list(new_cookie.items())
+                self.cookies = self.cookies + new_cookie_list  # type: ignore
             except CookieError as exc:
                 client_logger.warning("Can not load response cookies: %s", exc)
         return self

tests/test_client_session.py

@@ -2,8 +2,8 @@
 import contextlib
 import gc
 import json
-import sys
-from http.cookies import SimpleCookie
+import re
+from http.cookies import Morsel
 from io import BytesIO
 from unittest import mock
 
@@ -506,9 +506,11 @@ async def handler(request):
     # Updating the cookie jar with the response cookies
     assert jar.update_cookies.called
     resp_cookies = jar.update_cookies.call_args[0][0]
-    assert isinstance(resp_cookies, SimpleCookie)
-    assert "response" in resp_cookies
-    assert resp_cookies["response"].value == "resp_value"
+    assert isinstance(resp_cookies, list)
+    assert isinstance(resp_cookies[0], tuple)
+    assert isinstance(resp_cookies[0][1], Morsel)
+    assert "response" == resp_cookies[0][0]
+    assert "resp_value" == resp_cookies[0][1].coded_value
 
 
 async def test_session_default_version(loop) -> None: