From f49789bfd046f8ce7eec5c8b9ea7f720fbe90833 Mon Sep 17 00:00:00 2001
From: Eric Eastwood <erice@element.io>
Date: Tue, 20 May 2025 13:03:49 -0500
Subject: [PATCH] Fix `LruCache` `@overload`

---
 synapse/federation/federation_server.py      | 11 ++++++++---
 synapse/storage/databases/main/client_ips.py |  4 +++-
 synapse/util/caches/lrucache.py              |  5 +----
 tests/util/test_lrucache.py                  |  7 ++++++-
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 61cd4a85e4..41d54dfde9 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -141,7 +141,10 @@ class FederationServer(FederationBase):
 
         # We cache results for transaction with the same ID
         self._transaction_resp_cache: ResponseCache[Tuple[str, str]] = ResponseCache(
-            hs.get_clock(), "fed_txn_handler", timeout_ms=30000
+            hs.get_clock(),
+            hs.get_cache_manager(),
+            "fed_txn_handler",
+            timeout_ms=30000,
         )
 
         self.transaction_actions = TransactionActions(self.store)
@@ -154,13 +157,15 @@ class FederationServer(FederationBase):
             ResponseCache(
                 hs.get_clock(),
                 hs.get_cache_manager(),
-                hs.get_cache_manager(),
                 "state_resp",
                 timeout_ms=30000,
             )
         )
         self._state_ids_resp_cache: ResponseCache[Tuple[str, str]] = ResponseCache(
-            hs.get_clock(), hs.get_cache_manager(), "state_ids_resp", timeout_ms=30000
+            hs.get_clock(),
+            hs.get_cache_manager(),
+            "state_ids_resp",
+            timeout_ms=30000,
         )
 
         self._federation_metrics_domains = (
diff --git a/synapse/storage/databases/main/client_ips.py b/synapse/storage/databases/main/client_ips.py
index e8c322ab5c..1798ac00f3 100644
--- a/synapse/storage/databases/main/client_ips.py
+++ b/synapse/storage/databases/main/client_ips.py
@@ -434,7 +434,9 @@ class ClientIpWorkerStore(ClientIpBackgroundUpdateStore, MonthlyActiveUsersWorke
 
         # (user_id, access_token, ip,) -> last_seen
         self.client_ip_last_seen = LruCache[Tuple[str, str, str], int](
-            cache_name="client_ip_last_seen", max_size=50000
+            max_size=50000,
+            cache_name="client_ip_last_seen",
+            cache_manager=hs.get_cache_manager(),
         )
 
         if hs.config.worker.run_background_tasks and self.user_ips_max_age:
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 0a87a79228..0bbcd49382 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -397,15 +397,12 @@ class LruCache(Generic[KT, VT]):
     ): ...
 
     # If you're *not* providing in the `cache_name`, then you shouldn't provide the
-    # `cache_manager`
+    # `cache_manager` or the `metrics_collection_callback`
     @overload
     def __init__(
         self,
         max_size: int,
         *,
-        cache_name: Literal[None],
-        cache_manager: Literal[None],
-        metrics_collection_callback: Literal[None],
         cache_type: Type[Union[dict, TreeCache]] = dict,
         size_callback: Optional[Callable[[VT], int]] = None,
         apply_cache_factor_from_config: bool = True,
diff --git a/tests/util/test_lrucache.py b/tests/util/test_lrucache.py
index af9bb15f9e..2a8b3804b9 100644
--- a/tests/util/test_lrucache.py
+++ b/tests/util/test_lrucache.py
@@ -96,7 +96,12 @@ class LruCacheTestCase(unittest.HomeserverTestCase):
 
     @override_config({"caches": {"per_cache_factors": {"mycache": 10}}})
     def test_special_size(self) -> None:
-        cache: LruCache = LruCache(10, "mycache")
+        cache: LruCache = LruCache(
+            10,
+            cache_name="mycache",
+            # TODO
+            # cache_manager=TODO
+        )
         self.assertEqual(cache.max_size, 100)