From ee0a7091675d1e4eaa9c5de314a54a593503e3fe Mon Sep 17 00:00:00 2001
From: Jordan Cook <jordan.cook@corteva.com>
Date: Wed, 5 Aug 2026 13:30:50 -0500
Subject: [PATCH 1/2] Revert lru_cache for request lock to avoid binding to
 multiple event loops

---
 aiohttp_client_cache/session.py | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/aiohttp_client_cache/session.py b/aiohttp_client_cache/session.py
index 2e92b45..15e42f5 100644
--- a/aiohttp_client_cache/session.py
+++ b/aiohttp_client_cache/session.py
@@ -5,8 +5,8 @@
 import sys
 import warnings
 from asyncio import Lock
+from collections import defaultdict
 from contextlib import asynccontextmanager
-from functools import lru_cache
 from logging import getLogger
 from typing import TYPE_CHECKING, cast
 
@@ -49,11 +49,6 @@ async def __aexit__(self, *excinfo):
     from typing_extensions import Self
 
 
-@lru_cache(maxsize=16384)
-def _get_lock(_: int, __: str) -> Lock:
-    return Lock()
-
-
 class CacheMixin(MIXIN_BASE):
     """A mixin class for :py:class:`aiohttp.ClientSession` that adds caching support"""
 
@@ -66,6 +61,7 @@ def __init__(
         **kwargs,
     ):
         self.cache = cache or CacheBackend()
+        self._locks: dict[str, Lock] = defaultdict(Lock)
         self._null_lock = nullcontext()
 
         # Pass along any valid kwargs for ClientSession (or custom session superclass)
@@ -93,7 +89,7 @@ async def _request(
         if actions.skip_read:
             lock: Lock | nullcontext = self._null_lock
         else:
-            lock = _get_lock(id(self), key)
+            lock = self._locks[key]
 
         async with lock:
             response = await self.cache.request(actions)

From 9028e26c59edbd6463a17cfb949587e136833c22 Mon Sep 17 00:00:00 2001
From: Jordan Cook <jordan.cook@corteva.com>
Date: Wed, 5 Aug 2026 13:41:41 -0500
Subject: [PATCH 2/2] Use WeakValueDictionary to drop a key's Lock as soon as
 nothing is contending for it

---
 HISTORY.md                      |  1 +
 aiohttp_client_cache/session.py | 10 +++++++---
 test/unit/test_session.py       | 16 ++++++++++++++++
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/HISTORY.md b/HISTORY.md
index 2538981..5620d6f 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -3,6 +3,7 @@
 ## Not released
 
 - Added `_ExpandedRequestOptions.refresh` to satisfy Pyright type checking.
+- Revert `lru_cache` for request lock to avoid binding to multiple event loops (`RuntimeError: ...Lock is bound to a different event loop`)
 
 ## 0.14.3 (2026-01-07)
 
diff --git a/aiohttp_client_cache/session.py b/aiohttp_client_cache/session.py
index 15e42f5..a40fa9b 100644
--- a/aiohttp_client_cache/session.py
+++ b/aiohttp_client_cache/session.py
@@ -5,10 +5,10 @@
 import sys
 import warnings
 from asyncio import Lock
-from collections import defaultdict
 from contextlib import asynccontextmanager
 from logging import getLogger
 from typing import TYPE_CHECKING, cast
+from weakref import WeakValueDictionary
 
 from aiohttp import ClientSession
 from aiohttp.typedefs import StrOrURL
@@ -61,7 +61,8 @@ def __init__(
         **kwargs,
     ):
         self.cache = cache or CacheBackend()
-        self._locks: dict[str, Lock] = defaultdict(Lock)
+        # Drops a key's Lock as soon as nothing is contending for it
+        self._locks: WeakValueDictionary[str, Lock] = WeakValueDictionary()
         self._null_lock = nullcontext()
 
         # Pass along any valid kwargs for ClientSession (or custom session superclass)
@@ -89,7 +90,10 @@ async def _request(
         if actions.skip_read:
             lock: Lock | nullcontext = self._null_lock
         else:
-            lock = self._locks[key]
+            try:
+                lock = self._locks[key]
+            except KeyError:
+                lock = self._locks[key] = Lock()
 
         async with lock:
             response = await self.cache.request(actions)
diff --git a/test/unit/test_session.py b/test/unit/test_session.py
index 3a5c345..fb7f430 100644
--- a/test/unit/test_session.py
+++ b/test/unit/test_session.py
@@ -194,6 +194,22 @@ class CustomSession(CacheMixin, ClientSession):
     assert mock_request.called is False
 
 
+@patch.object(ClientSession, '_request', return_value=FakeClientResponse)
+async def test_session__locks_do_not_leak(mock_request):
+    """Locks are only needed while requests are actively contending for a cache key, so distinct
+    keys should not accumulate indefinitely.
+    """
+    cache = MagicMock(spec=CacheBackend)
+    cache.request.return_value = None
+    cache.create_key.side_effect = lambda method, url, **kwargs: str(url)
+
+    async with CachedSession(cache=cache) as session:
+        for i in range(1000):
+            await session.get(f'http://test.url/{i}')
+
+        assert len(session._locks) == 0
+
+
 @patch.object(ClientSession, '_request', return_value=FakeCachedResponse)
 async def test_session__cache_include_headers(mock_request):
     async with CachedSession(cache=CacheBackend(include_headers=True)) as session: