From 56ffcebdcfe0b1b39dde75673268aea1638ecabb Mon Sep 17 00:00:00 2001
From: Matthew Hodgson <matthew@matrix.org>
Date: Sat, 21 Mar 2026 21:12:46 +0000
Subject: [PATCH] =?UTF-8?q?=E2=8F=BA=20The=20remaining=20~79=20defer.*=20u?=
 =?UTF-8?q?sages=20are=20all=20in=20code=20that=20depends=20on=20the=20Twi?=
 =?UTF-8?q?sted=20reactor=20to=20schedule=20and=20resolve=20Deferreds.=20T?=
 =?UTF-8?q?hey'll=20be=20eliminated=20when=20the=20entry=20point=20switche?=
 =?UTF-8?q?s=20from=20reactor.run()=20to=20asyncio.run().=20At=20that=20po?=
 =?UTF-8?q?int:=20=20=20-=20defer.Deferred()=20=E2=86=92=20asyncio.Future(?=
 =?UTF-8?q?)=20or=20asyncio.Event()=20=20=20-=20defer.gatherResults()=20?=
 =?UTF-8?q?=E2=86=92=20asyncio.gather()=20=20=20-=20defer.succeed/fail=20?=
 =?UTF-8?q?=E2=86=92=20direct=20returns=20/=20asyncio.Future.set=5Fresult/?=
 =?UTF-8?q?set=5Fexception=20=20=20-=20defer.TimeoutError=20=E2=86=92=20as?=
 =?UTF-8?q?yncio.TimeoutError=20=20=20-=20defer.ensureDeferred=20=E2=86=92?=
 =?UTF-8?q?=20asyncio.ensure=5Ffuture=20or=20direct=20await=20=20=20-=20Li?=
 =?UTF-8?q?nearizer,=20ReadWriteLock,=20etc.=20=E2=86=92=20NativeLinearize?=
 =?UTF-8?q?r,=20NativeReadWriteLock?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 synapse/handlers/auth.py      |  2 +-
 synapse/logging/_remote.py    |  2 +-
 synapse/types/__init__.py     |  2 +-
 synapse/util/async_helpers.py | 18 +++++++++++++++---
 4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 8f5df65e4e..89163b615d 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -43,7 +43,7 @@ import unpaddedbase64
 from prometheus_client import Counter
 
 try:
-    from twisted.internet.defer import CancelledError
+    from asyncio import CancelledError
     from twisted.web.server import Request
 except ImportError:
     pass
diff --git a/synapse/logging/_remote.py b/synapse/logging/_remote.py
index 0ac1f584b4..300d1e10a4 100644
--- a/synapse/logging/_remote.py
+++ b/synapse/logging/_remote.py
@@ -36,7 +36,7 @@ except ImportError:
 
 try:
     from twisted.application.internet import ClientService
-    from twisted.internet.defer import CancelledError
+    from asyncio import CancelledError
     from twisted.internet.defer import Deferred
     from twisted.internet.endpoints import (
         HostnameEndpoint,
diff --git a/synapse/types/__init__.py b/synapse/types/__init__.py
index 09c71dfab0..400b5144aa 100644
--- a/synapse/types/__init__.py
+++ b/synapse/types/__init__.py
@@ -59,7 +59,7 @@ except ImportError:
     pass
 
 try:
-    from twisted.internet.defer import CancelledError
+    from asyncio import CancelledError
     from twisted.internet.interfaces import (
         IReactorCore,
         IReactorPluggableNameResolver,
diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index 80e1d5a944..97c6197252 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -1146,7 +1146,8 @@ class NativeLinearizer:
             # do work
     """
 
-    def __init__(self, name: str, max_count: int = 1) -> None:
+    def __init__(self, name: str, max_count: int = 1, clock: Any = None) -> None:
+        # clock parameter accepted for backward compatibility with Linearizer(clock=...)
         self.name = name
         self.max_count = max_count
         self._key_to_entry: dict[Hashable, _NativeLinearizerEntry] = {}
@@ -1350,7 +1351,8 @@ class NativeAwakenableSleeper:
     Allows explicit waking of sleeping coroutines by name.
     """
 
-    def __init__(self) -> None:
+    def __init__(self, clock: Any = None) -> None:
+        # clock parameter accepted for backward compatibility
         self._streams: dict[str, set[asyncio.Event]] = {}
 
     def wake(self, name: str) -> None:
@@ -1383,7 +1385,8 @@ class NativeEvent:
     Like threading.Event but for asyncio code.
     """
 
-    def __init__(self) -> None:
+    def __init__(self, clock: Any = None) -> None:
+        # clock parameter accepted for backward compatibility
         self._event = asyncio.Event()
 
     def set(self) -> None:
@@ -1490,3 +1493,12 @@ class DeferredEvent:
             pass
 
         return self.is_set()
+
+
+# ===========================================================================
+# The native asyncio versions (NativeLinearizer, NativeReadWriteLock,
+# NativeAwakenableSleeper, NativeEvent) are available above and will replace
+# the Deferred-based versions once the entry point switches from reactor.run()
+# to asyncio.run(). Until then, the old classes remain as they need the
+# Twisted reactor to drive their Deferred-based internals.
+# ===========================================================================