feat(autorun): add auto_await to AutorunOptions so that one can define an autorun/view as a decorator of a function without automatically awaiting its result, when auto_await is set to False, which activates the new behavior, the decorated function passes asyncio.iscoroutinefunction test, useful for certain libraries like quart

Author: sassanh

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Version 0.17.2
+
+- feat(autorun): add `auto_await` to `AutorunOptions` so that one can define an autorun/view as a decorator of a function without automatically awaiting its result, when `auto_await` is set to `False`, which activates the new behavior, the decorated function passes `asyncio.iscoroutinefunction` test, useful for certain libraries like quart
+
 ## Version 0.17.1
 
 - refactor(core): allow `None` type for state, action and event types in `ReducerResult` and `CompleteReducerResult`

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "python-redux"
-version = "0.17.1"
+version = "0.17.2"
 description = "Redux implementation for Python"
 authors = ["Sassan Haradji <sassanh@gmail.com>"]
 license = "Apache-2.0"

redux/autorun.py

@@ -1,11 +1,22 @@
 # ruff: noqa: D100, D101, D102, D103, D104, D105, D107
 from __future__ import annotations
 
+import asyncio
 import functools
 import inspect
 import weakref
 from asyncio import Future, Task, iscoroutine, iscoroutinefunction
-from typing import TYPE_CHECKING, Any, Callable, Concatenate, Generic, cast
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    Concatenate,
+    Coroutine,
+    Generator,
+    Generic,
+    TypeVar,
+    cast,
+)
 
 from redux.basic_types import (
     Action,
@@ -22,6 +33,25 @@
     from redux.main import Store
 
 
+T = TypeVar('T')
+
+
+class AwaitableWrapper(Generic[T]):
+    def __init__(self, coro: Coroutine[None, None, T]) -> None:
+        self.coro = coro
+        self.awaited = False
+
+    def __await__(self) -> Generator[None, None, T]:
+        self.awaited = True
+        return self.coro.__await__()
+
+    def close(self) -> None:
+        self.coro.close()
+
+    def __repr__(self) -> str:
+        return f'AwaitableWrapper({self.coro}, awaited={self.awaited})'
+
+
 class Autorun(
     Generic[
         State,
@@ -45,6 +75,7 @@ def __init__(
         ],
         options: AutorunOptions[AutorunOriginalReturnType],
     ) -> None:
+        self.__name__ = func.__name__
         self._store = store
         self._selector = selector
         self._comparator = comparator
@@ -55,6 +86,11 @@ def __init__(
             self._func = weakref.WeakMethod(func, self.unsubscribe)
         else:
             self._func = weakref.ref(func, self.unsubscribe)
+        self._is_coroutine = (
+            asyncio.coroutines._is_coroutine  # pyright: ignore [reportAttributeAccessIssue]  # noqa: SLF001
+            if asyncio.iscoroutinefunction(func) and not options.auto_await
+            else None
+        )
         self._options = options
 
         self._last_selector_result: SelectorOutput | None = None
@@ -120,11 +156,11 @@ def _task_callback(
         ],
         task: Task,
         *,
-        future: Future | None,
+        future: Future,
     ) -> None:
         task.add_done_callback(
             lambda result: (
-                future.set_result(result.result()) if future else None,
+                future.set_result(result.result()),
                 self.inform_subscribers(),
             ),
         )
@@ -184,15 +220,27 @@ def _call(
             )
             create_task = self._store._create_task  # noqa: SLF001
             if iscoroutine(value) and create_task:
-                future = Future()
-                self._latest_value = cast(AutorunOriginalReturnType, future)
-                create_task(
-                    value,
-                    callback=functools.partial(
-                        self._task_callback,
-                        future=future,
-                    ),
-                )
+                if self._options.auto_await:
+                    future = Future()
+                    self._latest_value = cast(AutorunOriginalReturnType, future)
+                    create_task(
+                        value,
+                        callback=functools.partial(
+                            self._task_callback,
+                            future=future,
+                        ),
+                    )
+                else:
+                    if (
+                        self._latest_value is not None
+                        and isinstance(self._latest_value, AwaitableWrapper)
+                        and not self._latest_value.awaited
+                    ):
+                        self._latest_value.close()
+                    self._latest_value = cast(
+                        AutorunOriginalReturnType,
+                        AwaitableWrapper(value),
+                    )
             else:
                 self._latest_value = value
             self.inform_subscribers()

redux/basic_types.py

@@ -133,6 +133,7 @@ class CreateStoreOptions(Immutable, Generic[Action, Event]):
 
 class AutorunOptions(Immutable, Generic[AutorunOriginalReturnType]):
     default_value: AutorunOriginalReturnType | None = None
+    auto_await: bool = True
     initial_call: bool = True
     reactive: bool = True
     keep_ref: bool = True
@@ -167,6 +168,8 @@ def subscribe(
 
     def unsubscribe(self: AutorunReturnType) -> None: ...
 
+    __name__: str
+
 
 class AutorunDecorator(
     Protocol,

redux/main.py

@@ -388,6 +388,7 @@ def decorator(
                 func=cast(Callable, func),
                 options=AutorunOptions(
                     default_value=_options.default_value,
+                    auto_await=False,
                     initial_call=False,
                     reactive=False,
                     keep_ref=_options.keep_ref,

redux_pytest/fixtures/snapshot.py

@@ -128,9 +128,7 @@ def monitor(self: StoreSnapshot[State], selector: Callable[[State], Any]) -> Non
         """Monitor the state of the store and take snapshots."""
 
         @self.store.autorun(selector=selector)
-        def _(state: object | None) -> None:
-            if state is None:
-                return
+        def _(state: object) -> None:
             self.take(selector=lambda _: state)
 
     def close(self: StoreSnapshot[State]) -> None:

tests/test_async.py

@@ -24,7 +24,7 @@
 if TYPE_CHECKING:
     from redux_pytest.fixtures.event_loop import LoopThread
 
-INCREMENTS = 2
+INCREMENTS = 20
 
 
 class StateType(Immutable):
@@ -91,16 +91,18 @@ def test_autorun(
     event_loop: LoopThread,
 ) -> None:
     @store.autorun(lambda state: state.value)
-    async def _(value: int) -> int:
+    async def sync_mirror(value: int) -> int:
         await asyncio.sleep(value / 10)
         store.dispatch(SetMirroredValueAction(value=value))
         return value
 
+    assert not asyncio.iscoroutinefunction(sync_mirror)
+
     @store.autorun(
         lambda state: state.mirrored_value,
         lambda state: state.mirrored_value >= INCREMENTS,
     )
-    async def _(mirrored_value: int) -> None:
+    def _(mirrored_value: int) -> None:
         if mirrored_value < INCREMENTS:
             return
         event_loop.stop()
@@ -109,6 +111,36 @@ async def _(mirrored_value: int) -> None:
     dispatch_actions(store)
 
 
+def test_autorun_autoawait(
+    store: StoreType,
+    event_loop: LoopThread,
+) -> None:
+    @store.autorun(lambda state: state.value, options=AutorunOptions(auto_await=False))
+    async def sync_mirror(value: int) -> int:
+        store.dispatch(SetMirroredValueAction(value=value))
+        return value * 2
+
+    assert asyncio.iscoroutinefunction(sync_mirror)
+
+    @store.autorun(lambda state: (state.value, state.mirrored_value))
+    async def _(values: tuple[int, int]) -> None:
+        value, mirrored_value = values
+        if mirrored_value != value:
+            assert 'awaited=False' in str(sync_mirror())
+            await sync_mirror()
+            assert 'awaited=True' in str(sync_mirror())
+            with pytest.raises(
+                RuntimeError,
+                match=r'^cannot reuse already awaited coroutine$',
+            ):
+                await sync_mirror()
+        elif value < INCREMENTS:
+            store.dispatch(IncrementAction())
+        else:
+            event_loop.stop()
+            store.dispatch(FinishAction())
+
+
 def test_autorun_default_value(
     store: StoreType,
     event_loop: LoopThread,
@@ -122,7 +154,7 @@ async def _(value: int) -> int:
         lambda state: state.mirrored_value,
         lambda state: state.mirrored_value >= INCREMENTS,
     )
-    async def _(mirrored_value: int) -> None:
+    def _(mirrored_value: int) -> None:
         if mirrored_value < INCREMENTS:
             return
         event_loop.stop()
@@ -145,7 +177,10 @@ async def doubled(value: int) -> int:
     @store.autorun(lambda state: state.value)
     async def _(value: int) -> None:
         assert await doubled() == value * 2
-        for _ in range(10):
+        with pytest.raises(
+            RuntimeError,
+            match=r'^cannot reuse already awaited coroutine$',
+        ):
             await doubled()
         if value < INCREMENTS:
             store.dispatch(IncrementAction())
@@ -155,6 +190,30 @@ async def _(value: int) -> None:
             assert calls == list(range(INCREMENTS + 1))
 
 
+def test_view_await(store: StoreType, event_loop: LoopThread) -> None:
+    calls = []
+
+    @store.view(lambda state: state.value)
+    async def doubled(value: int) -> int:
+        calls.append(value)
+        return value * 2
+
+    assert asyncio.iscoroutinefunction(doubled)
+
+    @store.autorun(lambda state: state.value)
+    async def _(value: int) -> None:
+        calls_length = len(calls)
+        assert await doubled() == value * 2
+        assert len(calls) == calls_length + 1
+
+        if value < INCREMENTS:
+            store.dispatch(IncrementAction())
+        else:
+            event_loop.stop()
+            store.dispatch(FinishAction())
+            assert calls == list(range(INCREMENTS + 1))
+
+
 def test_view_with_args(
     store: StoreType,
     event_loop: LoopThread,

tests/test_autorun.py

@@ -82,10 +82,12 @@ def store() -> Generator[StoreType, None, None]:
 
 def test_general(store_snapshot: StoreSnapshot, store: StoreType) -> None:
     @store.autorun(lambda state: state.value)
-    def _(value: int) -> int:
+    def decorated(value: int) -> int:
         store_snapshot.take()
         return value
 
+    assert decorated.__name__ == 'decorated'
+
 
 def test_ignore_attribute_error_in_selector(store: StoreType) -> None:
     @store.autorun(lambda state: cast(Any, state).non_existing)