1 files changed, 10 insertions, 2 deletions
diff --git a/synapse/http/client.py b/synapse/http/client.py
index d4ab3a2732..1e01e0a9f2 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -45,7 +45,9 @@ from twisted.internet.interfaces import (
     IHostResolution,
     IReactorPluggableNameResolver,
     IResolutionReceiver,
+    ITCPTransport,
 )
+from twisted.internet.protocol import connectionDone
 from twisted.internet.task import Cooperator
 from twisted.python.failure import Failure
 from twisted.web._newclient import ResponseDone
@@ -760,6 +762,8 @@ class BodyExceededMaxSize(Exception):
 class _DiscardBodyWithMaxSizeProtocol(protocol.Protocol):
     """A protocol which immediately errors upon receiving data."""
 
+    transport = None  # type: Optional[ITCPTransport]
+
     def __init__(self, deferred: defer.Deferred):
         self.deferred = deferred
 
@@ -771,18 +775,21 @@ class _DiscardBodyWithMaxSizeProtocol(protocol.Protocol):
             self.deferred.errback(BodyExceededMaxSize())
             # Close the connection (forcefully) since all the data will get
             # discarded anyway.
+            assert self.transport is not None
             self.transport.abortConnection()
 
     def dataReceived(self, data: bytes) -> None:
         self._maybe_fail()
 
-    def connectionLost(self, reason: Failure) -> None:
+    def connectionLost(self, reason: Failure = connectionDone) -> None:
         self._maybe_fail()
 
 
 class _ReadBodyWithMaxSizeProtocol(protocol.Protocol):
     """A protocol which reads body to a stream, erroring if the body exceeds a maximum size."""
 
+    transport = None  # type: Optional[ITCPTransport]
+
     def __init__(
         self, stream: BinaryIO, deferred: defer.Deferred, max_size: Optional[int]
     ):
@@ -805,9 +812,10 @@ class _ReadBodyWithMaxSizeProtocol(protocol.Protocol):
             self.deferred.errback(BodyExceededMaxSize())
             # Close the connection (forcefully) since all the data will get
             # discarded anyway.
+            assert self.transport is not None
             self.transport.abortConnection()
 
-    def connectionLost(self, reason: Failure) -> None:
+    def connectionLost(self, reason: Failure = connectionDone) -> None:
         # If the maximum size was already exceeded, there's nothing to do.
         if self.deferred.called:
             return