Handle response with multiple same name cookies

Closes aio-libs#4486

aiohttp/client_reqrep.py

@@ -6,7 +6,7 @@
 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 (  # noqa
     TYPE_CHECKING,
@@ -689,7 +689,7 @@ def __init__(self, method: str, url: URL, *,
         assert isinstance(url, URL)
 
         self.method = method
-        self.cookies = SimpleCookie()
+        self.cookies = []  # type: List[Tuple[str, BaseCookie[str]]]
 
         self._real_url = url
         self._url = url.with_fragment(None)
@@ -877,7 +877,10 @@ 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)

tests/test_client_request.py

@@ -1274,6 +1274,62 @@ async def create_connection(req, traces, timeout):
     await session.close()
     conn.close()
 
+async def test_custom_req_rep_same_cookie_diff_domain(loop) -> None:
+    conn = None
+
+    class CustomResponse(ClientResponse):
+
+        async def start(self, connection, read_until_eof=False):
+            nonlocal conn
+            conn = connection
+            self.status = 123
+            self.reason = 'Test OK'
+            self._headers = CIMultiDictProxy(CIMultiDict())
+            self.cookies = (
+                list(SimpleCookie("cookie=first; Domain=example.com; Path=/; ").items()) +
+                list(SimpleCookie("cookie=second; Domain=test1.example.com; Path=/; ").items()) +
+                list(SimpleCookie("cookie=third; Domain=test2.example.com; Path=/; ").items()))
+            return
+
+    called = False
+
+    class CustomRequest(ClientRequest):
+
+        async def send(self, conn):
+            resp = self.response_class(self.method,
+                                       self.url,
+                                       writer=self._writer,
+                                       continue100=self._continue,
+                                       timer=self._timer,
+                                       request_info=self.request_info,
+                                       traces=self._traces,
+                                       loop=self.loop,
+                                       session=self._session)
+            self.response = resp
+            nonlocal called
+            called = True
+            return resp
+
+    async def create_connection(req, traces, timeout):
+        assert isinstance(req, CustomRequest)
+        return mock.Mock()
+    connector = BaseConnector(loop=loop)
+    connector._create_connection = create_connection
+
+    session = aiohttp.ClientSession(
+        request_class=CustomRequest,
+        response_class=CustomResponse,
+        connector=connector,
+        loop=loop)
+
+    resp = await session.request(
+        'get', URL('http://example.com/path/to'))
+    assert isinstance(resp, CustomResponse)
+    assert called
+    assert len(resp.cookies) == 3
+    resp.close()
+    await session.close()
+    conn.close()
 
 def test_verify_ssl_false_with_ssl_context(loop, ssl_ctx) -> None:
     with pytest.warns(DeprecationWarning):