From 9a2f146a12e3525b43e96723ef41584bf9cf784e Mon Sep 17 00:00:00 2001
From: Cycloctane <Cycloctane@outlook.com>
Date: Sun, 21 Sep 2025 17:01:43 +0800
Subject: [PATCH] Ignore partitioned attributes in cookies if it is not
 supported by http.cookie (#11529)

---
 CHANGES/11523.bugfix.rst     |  2 ++
 aiohttp/_cookie_helpers.py   |  8 ++------
 tests/test_cookie_helpers.py | 33 +++++++++++++++++++++++++++++++++
 tests/test_cookiejar.py      | 13 +++++++++++++
 4 files changed, 50 insertions(+), 6 deletions(-)
 create mode 100644 CHANGES/11523.bugfix.rst

diff --git a/CHANGES/11523.bugfix.rst b/CHANGES/11523.bugfix.rst
new file mode 100644
index 00000000000..7b70bcf6e76
--- /dev/null
+++ b/CHANGES/11523.bugfix.rst
@@ -0,0 +1,2 @@
+Fix saved ``CookieJar`` fail to be loaded if cookies have ``partitioned`` flag when
+``http.cookie`` does not have partitioned cookies supports. -- by :user:`Cycloctane`.
diff --git a/aiohttp/_cookie_helpers.py b/aiohttp/_cookie_helpers.py
index 4e9fc968814..9e80b6065d7 100644
--- a/aiohttp/_cookie_helpers.py
+++ b/aiohttp/_cookie_helpers.py
@@ -6,7 +6,6 @@
 """
 
 import re
-import sys
 from http.cookies import Morsel
 from typing import List, Optional, Sequence, Tuple, cast
 
@@ -270,11 +269,8 @@ def parse_set_cookie_headers(headers: Sequence[str]) -> List[Tuple[str, Morsel[s
                     break
                 if lower_key in _COOKIE_BOOL_ATTRS:
                     # Boolean attribute with any value should be True
-                    if current_morsel is not None:
-                        if lower_key == "partitioned" and sys.version_info < (3, 14):
-                            dict.__setitem__(current_morsel, lower_key, True)
-                        else:
-                            current_morsel[lower_key] = True
+                    if current_morsel is not None and current_morsel.isReservedKey(key):
+                        current_morsel[lower_key] = True
                 elif value is None:
                     # Invalid cookie string - non-boolean attribute without value
                     break
diff --git a/tests/test_cookie_helpers.py b/tests/test_cookie_helpers.py
index 6deef6544c2..0ec393e2b79 100644
--- a/tests/test_cookie_helpers.py
+++ b/tests/test_cookie_helpers.py
@@ -1,5 +1,6 @@
 """Tests for internal cookie helper functions."""
 
+import sys
 from http.cookies import (
     CookieError,
     Morsel,
@@ -427,6 +428,10 @@ def test_parse_set_cookie_headers_boolean_attrs() -> None:
         assert morsel.get("httponly") is True, f"{name} should have httponly=True"
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 14),
+    reason="Partitioned cookies support requires Python 3.14+",
+)
 def test_parse_set_cookie_headers_boolean_attrs_with_partitioned() -> None:
     """Test that boolean attributes including partitioned work correctly."""
     # Test secure attribute variations
@@ -482,6 +487,10 @@ def test_parse_set_cookie_headers_encoded_values() -> None:
     assert result[2][1].value == "%21%40%23%24%25%5E%26*%28%29"
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 14),
+    reason="Partitioned cookies support requires Python 3.14+",
+)
 def test_parse_set_cookie_headers_partitioned() -> None:
     """
     Test that parse_set_cookie_headers handles partitioned attribute correctly.
@@ -518,6 +527,10 @@ def test_parse_set_cookie_headers_partitioned() -> None:
     assert result[4][1].get("path") == "/"
 
 
+@pytest.mark.skipif(
+    sys.version_info < (3, 14),
+    reason="Partitioned cookies support requires Python 3.14+",
+)
 def test_parse_set_cookie_headers_partitioned_case_insensitive() -> None:
     """Test that partitioned attribute is recognized case-insensitively."""
     headers = [
@@ -555,6 +568,26 @@ def test_parse_set_cookie_headers_partitioned_not_set() -> None:
 
 
 # Tests that don't require partitioned support in SimpleCookie
+@pytest.mark.skipif(
+    sys.version_info >= (3, 14),
+    reason="Python 3.14+ has built-in partitioned cookie support",
+)
+def test_parse_set_cookie_headers_partitioned_not_set_if_no_support() -> None:
+    headers = [
+        "cookie1=value1; Partitioned",
+        "cookie2=value2; Partitioned=",
+        "cookie3=value3; Partitioned=true",
+    ]
+
+    result = parse_set_cookie_headers(headers)
+
+    assert len(result) == 3
+    for i, (_, morsel) in enumerate(result):
+        assert (
+            morsel.get("partitioned") is None
+        ), f"Cookie {i+1} should not have partitioned flag"
+
+
 def test_parse_set_cookie_headers_partitioned_with_other_attrs_manual() -> None:
     """
     Test parsing logic for partitioned cookies combined with all other attributes.
diff --git a/tests/test_cookiejar.py b/tests/test_cookiejar.py
index b3774140c63..25d9cc731e3 100644
--- a/tests/test_cookiejar.py
+++ b/tests/test_cookiejar.py
@@ -206,6 +206,19 @@ def test_save_load(
     assert jar_test == cookies_to_receive
 
 
+def test_save_load_partitioned_cookies(tmp_path: Path) -> None:
+    file_path = Path(str(tmp_path)) / "aiohttp.test2.cookie"
+    # export cookie jar
+    jar_save = CookieJar()
+    jar_save.update_cookies_from_headers(
+        ["session=cookie; Partitioned"], URL("https://example.com/")
+    )
+    jar_save.save(file_path=file_path)
+    jar_load = CookieJar()
+    jar_load.load(file_path=file_path)
+    assert jar_save._cookies == jar_load._cookies
+
+
 async def test_update_cookie_with_unicode_domain() -> None:
     cookies = (
         "idna-domain-first=first; Domain=xn--9caa.com; Path=/;",