diff options
Diffstat (limited to 'synapse/util/async_helpers.py')
| -rw-r--r-- | synapse/util/async_helpers.py | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py index 60c03a66fd..a9f67dcbac 100644 --- a/synapse/util/async_helpers.py +++ b/synapse/util/async_helpers.py @@ -40,7 +40,7 @@ from typing import ( ) import attr -from typing_extensions import ContextManager +from typing_extensions import ContextManager, Literal from twisted.internet import defer from twisted.internet.defer import CancelledError @@ -96,6 +96,10 @@ class ObservableDeferred(Generic[_T], AbstractObservableDeferred[_T]): __slots__ = ["_deferred", "_observers", "_result"] + _deferred: "defer.Deferred[_T]" + _observers: Union[List["defer.Deferred[_T]"], Tuple[()]] + _result: Union[None, Tuple[Literal[True], _T], Tuple[Literal[False], Failure]] + def __init__(self, deferred: "defer.Deferred[_T]", consumeErrors: bool = False): object.__setattr__(self, "_deferred", deferred) object.__setattr__(self, "_result", None) @@ -158,12 +162,14 @@ class ObservableDeferred(Generic[_T], AbstractObservableDeferred[_T]): effect the underlying deferred. """ if not self._result: + assert isinstance(self._observers, list) d: "defer.Deferred[_T]" = defer.Deferred() self._observers.append(d) return d + elif self._result[0]: + return defer.succeed(self._result[1]) else: - success, res = self._result - return defer.succeed(res) if success else defer.fail(res) + return defer.fail(self._result[1]) def observers(self) -> "Collection[defer.Deferred[_T]]": return self._observers @@ -175,6 +181,8 @@ class ObservableDeferred(Generic[_T], AbstractObservableDeferred[_T]): return self._result is not None and self._result[0] is True def get_result(self) -> Union[_T, Failure]: + if self._result is None: + raise ValueError(f"{self!r} has no result yet") return self._result[1] def __getattr__(self, name: str) -> Any: |