Pass str to twisted's IReactorTCP (#10895)

This follows a correction made in twisted/twisted#1664 and should fix our Twisted Trial CI job.

Until that change is in a twisted release, we'll have to ignore the type
of the `host` argument. I've raised #10899 to remind us to review the
issue in a few months' time.

6 files changed, 27 insertions, 11 deletions

diff --git a/changelog.d/10895.misc b/changelog.d/10895.misc
new file mode 100644
index 0000000000..d1c8224980
--- /dev/null
+++ b/changelog.d/10895.misc
@@ -0,0 +1 @@
+Fix type hints to be compatible with an upcoming change to Twisted.
\ No newline at end of file
diff --git a/synapse/handlers/send_email.py b/synapse/handlers/send_email.py
index 25e6b012b7..1a062a784c 100644
--- a/synapse/handlers/send_email.py
+++ b/synapse/handlers/send_email.py
@@ -105,8 +105,13 @@ async def _sendmail(
         # set to enable TLS.
         factory = build_sender_factory(hostname=smtphost if enable_tls else None)
 
-    # the IReactorTCP interface claims host has to be a bytes, which seems to be wrong
-    reactor.connectTCP(smtphost, smtpport, factory, timeout=30, bindAddress=None)  # type: ignore[arg-type]
+    reactor.connectTCP(
+        smtphost,  # type: ignore[arg-type]
+        smtpport,
+        factory,
+        timeout=30,
+        bindAddress=None,
+    )
 
     await make_deferred_yieldable(d)
 
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index 1438a82b60..d64d1dbacd 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -315,7 +315,7 @@ class ReplicationCommandHandler:
                 hs, outbound_redis_connection
             )
             hs.get_reactor().connectTCP(
-                hs.config.redis.redis_host.encode(),
+                hs.config.redis.redis_host,  # type: ignore[arg-type]
                 hs.config.redis.redis_port,
                 self._factory,
             )
@@ -324,7 +324,11 @@ class ReplicationCommandHandler:
             self._factory = DirectTcpReplicationClientFactory(hs, client_name, self)
             host = hs.config.worker.worker_replication_host
             port = hs.config.worker.worker_replication_port
-            hs.get_reactor().connectTCP(host.encode(), port, self._factory)
+            hs.get_reactor().connectTCP(
+                host,  # type: ignore[arg-type]
+                port,
+                self._factory,
+            )
 
     def get_streams(self) -> Dict[str, Stream]:
         """Get a map from stream name to all streams."""
diff --git a/synapse/replication/tcp/redis.py b/synapse/replication/tcp/redis.py
index 8c0df627c8..062fe2f33e 100644
--- a/synapse/replication/tcp/redis.py
+++ b/synapse/replication/tcp/redis.py
@@ -364,6 +364,12 @@ def lazyConnection(
     factory.continueTrying = reconnect
 
     reactor = hs.get_reactor()
-    reactor.connectTCP(host.encode(), port, factory, timeout=30, bindAddress=None)
+    reactor.connectTCP(
+        host,  # type: ignore[arg-type]
+        port,
+        factory,
+        timeout=30,
+        bindAddress=None,
+    )
 
     return factory.handler
diff --git a/tests/replication/_base.py b/tests/replication/_base.py
index c7555c26db..cdd6e3d3c1 100644
--- a/tests/replication/_base.py
+++ b/tests/replication/_base.py
@@ -240,7 +240,7 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         if self.hs.config.redis.redis_enabled:
             # Handle attempts to connect to fake redis server.
             self.reactor.add_tcp_client_callback(
-                b"localhost",
+                "localhost",
                 6379,
                 self.connect_any_redis_attempts,
             )
@@ -424,7 +424,7 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         clients = self.reactor.tcpClients
         while clients:
             (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
-            self.assertEqual(host, b"localhost")
+            self.assertEqual(host, "localhost")
             self.assertEqual(port, 6379)
 
             client_protocol = client_factory.buildProtocol(None)
diff --git a/tests/server.py b/tests/server.py
index 88dfa8058e..64645651ce 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -317,7 +317,7 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
     def __init__(self):
         self.threadpool = ThreadPool(self)
 
-        self._tcp_callbacks = {}
+        self._tcp_callbacks: Dict[Tuple[str, int], Callable] = {}
         self._udp = []
         self.lookups: Dict[str, str] = {}
         self._thread_callbacks: Deque[Callable[[], None]] = deque()
@@ -355,7 +355,7 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
     def getThreadPool(self):
         return self.threadpool
 
-    def add_tcp_client_callback(self, host, port, callback):
+    def add_tcp_client_callback(self, host: str, port: int, callback: Callable):
         """Add a callback that will be invoked when we receive a connection
         attempt to the given IP/port using `connectTCP`.
 
@@ -364,7 +364,7 @@ class ThreadedMemoryReactorClock(MemoryReactorClock):
         """
         self._tcp_callbacks[(host, port)] = callback
 
-    def connectTCP(self, host, port, factory, timeout=30, bindAddress=None):
+    def connectTCP(self, host: str, port: int, factory, timeout=30, bindAddress=None):
         """Fake L{IReactorTCP.connectTCP}."""
 
         conn = super().connectTCP(
@@ -475,7 +475,7 @@ def setup_test_homeserver(cleanup_func, *args, **kwargs):
     return server
 
 
-def get_clock():
+def get_clock() -> Tuple[ThreadedMemoryReactorClock, Clock]:
     clock = ThreadedMemoryReactorClock()
     hs_clock = Clock(clock)
     return clock, hs_clock