From d8bab6793c75774db4bde8aeec6897b607e08799 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <clokep@users.noreply.github.com>
Date: Tue, 8 Mar 2022 07:26:05 -0500
Subject: [PATCH] Fix incorrect type hints for txredis. (#12042)

Some properties were marked as RedisProtocol instead of ConnectionHandler,
which wraps RedisProtocol instance(s).
---
 changelog.d/12042.misc                    | 1 +
 stubs/txredisapi.pyi                      | 9 ++++++---
 synapse/replication/tcp/external_cache.py | 4 ++--
 synapse/replication/tcp/redis.py          | 6 +++---
 synapse/server.py                         | 4 ++--
 5 files changed, 14 insertions(+), 10 deletions(-)
 create mode 100644 changelog.d/12042.misc

diff --git a/changelog.d/12042.misc b/changelog.d/12042.misc
new file mode 100644
index 000000000000..6ecdc960210c
--- /dev/null
+++ b/changelog.d/12042.misc
@@ -0,0 +1 @@
+Correct type hints for txredis.
diff --git a/stubs/txredisapi.pyi b/stubs/txredisapi.pyi
index 429234d7ae7f..2d8ca018fbfc 100644
--- a/stubs/txredisapi.pyi
+++ b/stubs/txredisapi.pyi
@@ -20,7 +20,7 @@ from twisted.internet import protocol
 from twisted.internet.defer import Deferred
 
 class RedisProtocol(protocol.Protocol):
-    def publish(self, channel: str, message: bytes): ...
+    def publish(self, channel: str, message: bytes) -> "Deferred[None]": ...
     def ping(self) -> "Deferred[None]": ...
     def set(
         self,
@@ -52,11 +52,14 @@ def lazyConnection(
     convertNumbers: bool = ...,
 ) -> RedisProtocol: ...
 
-class ConnectionHandler: ...
+# ConnectionHandler doesn't actually inherit from RedisProtocol, but it proxies
+# most methods to it via ConnectionHandler.__getattr__.
+class ConnectionHandler(RedisProtocol):
+    def disconnect(self) -> "Deferred[None]": ...
 
 class RedisFactory(protocol.ReconnectingClientFactory):
     continueTrying: bool
-    handler: RedisProtocol
+    handler: ConnectionHandler
     pool: List[RedisProtocol]
     replyTimeout: Optional[int]
     def __init__(
diff --git a/synapse/replication/tcp/external_cache.py b/synapse/replication/tcp/external_cache.py
index aaf91e5e0253..bf7d017968f9 100644
--- a/synapse/replication/tcp/external_cache.py
+++ b/synapse/replication/tcp/external_cache.py
@@ -21,7 +21,7 @@
 from synapse.util import json_decoder, json_encoder
 
 if TYPE_CHECKING:
-    from txredisapi import RedisProtocol
+    from txredisapi import ConnectionHandler
 
     from synapse.server import HomeServer
 
@@ -63,7 +63,7 @@ class ExternalCache:
     def __init__(self, hs: "HomeServer"):
         if hs.config.redis.redis_enabled:
             self._redis_connection: Optional[
-                "RedisProtocol"
+                "ConnectionHandler"
             ] = hs.get_outbound_redis_connection()
         else:
             self._redis_connection = None
diff --git a/synapse/replication/tcp/redis.py b/synapse/replication/tcp/redis.py
index 3170f7c59b04..b84e572da136 100644
--- a/synapse/replication/tcp/redis.py
+++ b/synapse/replication/tcp/redis.py
@@ -93,7 +93,7 @@ class RedisSubscriber(txredisapi.SubscriberProtocol):
 
     synapse_handler: "ReplicationCommandHandler"
     synapse_stream_name: str
-    synapse_outbound_redis_connection: txredisapi.RedisProtocol
+    synapse_outbound_redis_connection: txredisapi.ConnectionHandler
 
     def __init__(self, *args: Any, **kwargs: Any):
         super().__init__(*args, **kwargs)
@@ -313,7 +313,7 @@ class RedisDirectTcpReplicationClientFactory(SynapseRedisFactory):
     protocol = RedisSubscriber
 
     def __init__(
-        self, hs: "HomeServer", outbound_redis_connection: txredisapi.RedisProtocol
+        self, hs: "HomeServer", outbound_redis_connection: txredisapi.ConnectionHandler
     ):
 
         super().__init__(
@@ -353,7 +353,7 @@ def lazyConnection(
     reconnect: bool = True,
     password: Optional[str] = None,
     replyTimeout: int = 30,
-) -> txredisapi.RedisProtocol:
+) -> txredisapi.ConnectionHandler:
     """Creates a connection to Redis that is lazily set up and reconnects if the
     connections is lost.
     """
diff --git a/synapse/server.py b/synapse/server.py
index b5e2a319bcef..46a64418ea0c 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -145,7 +145,7 @@
 logger = logging.getLogger(__name__)
 
 if TYPE_CHECKING:
-    from txredisapi import RedisProtocol
+    from txredisapi import ConnectionHandler
 
     from synapse.handlers.oidc import OidcHandler
     from synapse.handlers.saml import SamlHandler
@@ -807,7 +807,7 @@ def get_account_handler(self) -> AccountHandler:
         return AccountHandler(self)
 
     @cache_in_self
-    def get_outbound_redis_connection(self) -> "RedisProtocol":
+    def get_outbound_redis_connection(self) -> "ConnectionHandler":
         """
         The Redis connection used for replication.