Generics for ObservableDeferred (#10491)

Now that `Deferred` is a generic class, let's update `ObeservableDeferred` to
follow suit.
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Richard van der Hoff 2021-07-28 20:55:50 +01:00 committed by GitHub
parent d0b294ad97
commit 858363d0b7
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4 changed files with 15 additions and 9 deletions

1
changelog.d/10491.misc Normal file
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@ -0,0 +1 @@
Improve type annotations for `ObservableDeferred`.

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@ -111,8 +111,9 @@ class _NotifierUserStream:
self.last_notified_token = current_token
self.last_notified_ms = time_now_ms
with PreserveLoggingContext():
self.notify_deferred = ObservableDeferred(defer.Deferred())
self.notify_deferred: ObservableDeferred[StreamToken] = ObservableDeferred(
defer.Deferred()
)
def notify(
self,

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@ -170,7 +170,9 @@ class _EventPeristenceQueue(Generic[_PersistResult]):
end_item = queue[-1]
else:
# need to make a new queue item
deferred = ObservableDeferred(defer.Deferred(), consumeErrors=True)
deferred: ObservableDeferred[_PersistResult] = ObservableDeferred(
defer.Deferred(), consumeErrors=True
)
end_item = _EventPersistQueueItem(
events_and_contexts=[],

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@ -23,6 +23,7 @@ from typing import (
Awaitable,
Callable,
Dict,
Generic,
Hashable,
Iterable,
List,
@ -39,6 +40,7 @@ from twisted.internet import defer
from twisted.internet.defer import CancelledError
from twisted.internet.interfaces import IReactorTime
from twisted.python import failure
from twisted.python.failure import Failure
from synapse.logging.context import (
PreserveLoggingContext,
@ -52,7 +54,7 @@ logger = logging.getLogger(__name__)
_T = TypeVar("_T")
class ObservableDeferred:
class ObservableDeferred(Generic[_T]):
"""Wraps a deferred object so that we can add observer deferreds. These
observer deferreds do not affect the callback chain of the original
deferred.
@ -70,7 +72,7 @@ class ObservableDeferred:
__slots__ = ["_deferred", "_observers", "_result"]
def __init__(self, deferred: defer.Deferred, consumeErrors: bool = False):
def __init__(self, deferred: "defer.Deferred[_T]", consumeErrors: bool = False):
object.__setattr__(self, "_deferred", deferred)
object.__setattr__(self, "_result", None)
object.__setattr__(self, "_observers", set())
@ -115,7 +117,7 @@ class ObservableDeferred:
deferred.addCallbacks(callback, errback)
def observe(self) -> defer.Deferred:
def observe(self) -> "defer.Deferred[_T]":
"""Observe the underlying deferred.
This returns a brand new deferred that is resolved when the underlying
@ -123,7 +125,7 @@ class ObservableDeferred:
effect the underlying deferred.
"""
if not self._result:
d: "defer.Deferred[Any]" = defer.Deferred()
d: "defer.Deferred[_T]" = defer.Deferred()
def remove(r):
self._observers.discard(d)
@ -137,7 +139,7 @@ class ObservableDeferred:
success, res = self._result
return defer.succeed(res) if success else defer.fail(res)
def observers(self) -> List[defer.Deferred]:
def observers(self) -> "List[defer.Deferred[_T]]":
return self._observers
def has_called(self) -> bool:
@ -146,7 +148,7 @@ class ObservableDeferred:
def has_succeeded(self) -> bool:
return self._result is not None and self._result[0] is True
def get_result(self) -> Any:
def get_result(self) -> Union[_T, Failure]:
return self._result[1]
def __getattr__(self, name: str) -> Any: