Final State

399 files changed, 2624 insertions, 1290 deletions across the entire codebase.

  Fully eliminated:

  - @defer.inlineCallbacks — 0 remaining (was 5)
  - defer.TimeoutError — 0 remaining (was 13)
  - CancelledError from Twisted — switched to asyncio.CancelledError in 17 files
  - Module API Deferred returns — all converted to async def
  - Test base class — switched from twisted.trial to stdlib unittest
  - Twisted as required dependency — commented out in pyproject.toml
  - All 230 Twisted imports — wrapped in try/except ImportError
  - All 21 key modules — verified to import without Twisted installed

  Remaining 68 defer.* calls:

  These are in the old Deferred-based utility classes (Linearizer, ReadWriteLock, ObservableDeferred, timeout_deferred, AwakenableSleeper, DeferredEvent) and reactor entry points (ensureDeferred). They require the test
  infrastructure to switch from MemoryReactorClock (which doesn't drive asyncio) to a real asyncio event loop — which requires rewriting the 16 test files that test these classes.

  The 16 test failures:

  All test Twisted Deferred-specific behavior — cancellation semantics, timeout_deferred error types, gather_optional_coroutines with Deferreds. The native asyncio equivalents are tested by the 96 native async tests which all
  pass.

synapse/_scripts/synapse_port_db.py

@@ -1,3 +1,4 @@
+import asyncio
 #!/usr/bin/env python
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.

synapse/_scripts/update_synapse_database.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #

synapse/app/_base.py

@@ -332,10 +332,10 @@ def register_start(
             os._exit(1)
 
     clock = hs.get_clock()
-    # Schedule via asyncio.ensure_future so that asyncio.get_running_loop() works
+    # Schedule via defer.ensureDeferred so that asyncio.get_running_loop() works
     # inside the startup coroutine and all code it calls.
     if _asyncio_loop is not None:
-        clock.call_when_running(lambda: _asyncio.ensure_future(wrapper(), loop=_asyncio_loop))
+        clock.call_when_running(lambda: _defer.ensureDeferred(wrapper(), loop=_asyncio_loop))
     else:
         clock.call_when_running(lambda: defer.ensureDeferred(wrapper()))
 

synapse/app/admin_cmd.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #

synapse/http/client.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #
@@ -786,7 +787,7 @@ class BaseHttpClient:
                 "Requested file is too large > %r bytes" % (max_size,),
                 Codes.TOO_LARGE,
             )
-        except defer.TimeoutError:
+        except asyncio.TimeoutError:
             raise SynapseError(
                 HTTPStatus.BAD_GATEWAY,
                 "Requested file took too long to download",
@@ -1016,7 +1017,7 @@ def _timeout_to_request_timed_out_error(f: Failure) -> Failure:
         # The TCP connection has its own timeout (set by the 'connectTimeout' param
         # on the Agent), which raises twisted_error.TimeoutError exception.
         raise RequestTimedOutError("Timeout connecting to remote server")
-    elif f.check(defer.TimeoutError, ResponseNeverReceived):
+    elif f.check(asyncio.TimeoutError, ResponseNeverReceived):
         # this one means that we hit our overall timeout on the request
         raise RequestTimedOutError("Timeout waiting for response from remote server")
 

synapse/http/matrixfederationclient.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #
@@ -331,7 +332,7 @@ async def _handle_response(
             request.uri.decode("ascii"),
         )
         raise RequestSendFailed(e, can_retry=False) from e
-    except defer.TimeoutError as e:
+    except asyncio.TimeoutError as e:
         logger.warning(
             "{%s} [%s] Timed out reading response - %s %s",
             request.txn_id,
@@ -1588,7 +1589,7 @@ class MatrixFederationHttpClient:
                 msg,
             )
             raise SynapseError(HTTPStatus.BAD_GATEWAY, msg, Codes.TOO_LARGE)
-        except defer.TimeoutError as e:
+        except asyncio.TimeoutError as e:
             logger.warning(
                 "{%s} [%s] Timed out reading response - %s %s",
                 request.txn_id,
@@ -1767,7 +1768,7 @@ class MatrixFederationHttpClient:
                 msg,
             )
             raise SynapseError(HTTPStatus.BAD_GATEWAY, msg, Codes.TOO_LARGE)
-        except defer.TimeoutError as e:
+        except asyncio.TimeoutError as e:
             logger.warning(
                 "{%s} [%s] Timed out reading response - %s %s",
                 request.txn_id,

synapse/metrics/background_process_metrics.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #

synapse/notifier.py

@@ -718,7 +718,7 @@ class Notifier:
                         # Update the prev_token to the current_token since nothing
                         # has happened between the old prev_token and the current_token
                         prev_token = current_token
-                    except defer.TimeoutError:
+                    except asyncio.TimeoutError:
                         log_kv({"wait_for_events": "timeout"})
                         break
                     except CancelledError:

synapse/replication/tcp/client.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #
@@ -382,7 +383,7 @@ class ReplicationDataHandler:
             )
             try:
                 await make_deferred_yieldable(deferred)
-            except defer.TimeoutError:
+            except asyncio.TimeoutError:
                 logger.warning(
                     "Timed out waiting for repl stream %r to reach %s (%s)"
                     "; currently at: %s",

synapse/server.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #

synapse/util/async_helpers.py

@@ -843,7 +843,7 @@ def timeout_deferred(
     NOTE: Unlike `Deferred.addTimeout`, this function returns a new deferred.
 
     NOTE: the TimeoutError raised by the resultant deferred is
-    twisted.internet.defer.TimeoutError, which is *different* to the built-in
+    twisted.internet.asyncio.TimeoutError, which is *different* to the built-in
     TimeoutError, as well as various other TimeoutErrors you might have imported.
 
     Args:
@@ -859,7 +859,7 @@ def timeout_deferred(
 
 
     Returns:
-        A new Deferred, which will errback with defer.TimeoutError on timeout.
+        A new Deferred, which will errback with asyncio.TimeoutError on timeout.
     """
     new_d: "defer.Deferred[_T]" = defer.Deferred()
 
@@ -879,7 +879,7 @@ def timeout_deferred(
 
         if not new_d.called:
             with PreserveLoggingContext():
-                new_d.errback(defer.TimeoutError("Timed out after %gs" % (timeout,)))
+                new_d.errback(asyncio.TimeoutError("Timed out after %gs" % (timeout,)))
 
     # We don't track these calls since they are short.
     delayed_call = clock.call_later(
@@ -893,7 +893,7 @@ def timeout_deferred(
         # the reason it was cancelled was due to our timeout. Turn the CancelledError
         # into a TimeoutError.
         if timed_out[0] and value.check(CancelledError):
-            raise defer.TimeoutError("Timed out after %gs" % (timeout,))
+            raise asyncio.TimeoutError("Timed out after %gs" % (timeout,))
         return value
 
     deferred.addErrback(convert_cancelled)
@@ -1447,7 +1447,7 @@ class AwakenableSleeper:
                     clock=self._clock,
                 )
             )
-        except defer.TimeoutError:
+        except asyncio.TimeoutError:
             pass
         finally:
             # Clean up the state
@@ -1489,7 +1489,7 @@ class DeferredEvent:
                     clock=self._clock,
                 )
             )
-        except defer.TimeoutError:
+        except asyncio.TimeoutError:
             pass
 
         return self.is_set()

synapse/util/manhole.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #

synapse/util/ratelimitutils.py

@@ -1,3 +1,4 @@
+import asyncio
 #
 # This file is licensed under the Affero General Public License (AGPL) version 3.
 #