fix: 🐛 @constant now works with async recipes

Author: remimd

injection/_core/common/lazy.py

@@ -1,41 +1,50 @@
-from collections.abc import Callable, Iterator
+from collections.abc import AsyncIterator, Awaitable, Callable, Iterator
 from functools import partial
 
-from injection._core.common.invertible import Invertible, SimpleInvertible
+from injection._core.common.invertible import Invertible
 
 
-def lazy[T](factory: Callable[..., T]) -> Invertible[T]:
+def lazy[T](factory: Callable[..., T]) -> Callable[[], T]:
     def cache() -> Iterator[T]:
-        nonlocal factory
         value = factory()
-        del factory
+        while True:
+            yield value
+
+    return partial(next, cache())
 
+
+def alazy[T](factory: Callable[..., Awaitable[T]]) -> Callable[[], Awaitable[T]]:
+    async def cache() -> AsyncIterator[T]:
+        value = await factory()
         while True:
             yield value
 
-    getter = partial(next, cache())
-    return SimpleInvertible(getter)
+    return partial(_anext, cache())
 
 
 class Lazy[T](Invertible[T]):
-    __slots__ = ("__invertible", "__is_set")
+    __slots__ = ("__get", "__is_set")
 
-    __invertible: Invertible[T]
+    __get: Callable[[], T]
     __is_set: bool
 
     def __init__(self, factory: Callable[..., T]) -> None:
         @lazy
-        def invertible() -> T:
+        def get() -> T:
             value = factory()
             self.__is_set = True
             return value
 
-        self.__invertible = invertible
+        self.__get = get
         self.__is_set = False
 
     def __invert__(self) -> T:
-        return ~self.__invertible
+        return self.__get()
 
     @property
     def is_set(self) -> bool:
         return self.__is_set
+
+
+async def _anext[T](async_iterator: AsyncIterator[T]) -> T:
+    return await anext(async_iterator)

injection/_core/module.py

@@ -50,7 +50,7 @@
 from injection._core.common.event import Event, EventChannel, EventListener
 from injection._core.common.invertible import Invertible, SimpleInvertible
 from injection._core.common.key import new_short_key
-from injection._core.common.lazy import Lazy, lazy
+from injection._core.common.lazy import Lazy, alazy, lazy
 from injection._core.common.threading import get_lock
 from injection._core.common.type import (
     InputType,
@@ -512,9 +512,9 @@ def constant[**P, T](
         mode: Mode | ModeStr = Mode.get_default(),
     ) -> Any:
         def decorator(wp: Recipe[P, T]) -> Recipe[P, T]:
-            lazy_instance = lazy(wp)
+            recipe: Recipe[[], T] = alazy(wp) if iscoroutinefunction(wp) else lazy(wp)  # type: ignore[arg-type]
             self.injectable(
-                lambda: ~lazy_instance,
+                recipe,
                 ignore_type_hint=True,
                 inject=False,
                 on=(wp, on),

tests/test_constant.py

@@ -1,6 +1,6 @@
 import pytest
 
-from injection import constant, get_instance
+from injection import aget_instance, constant, get_instance
 
 
 class TestConstant:
@@ -12,6 +12,33 @@ class SomeInjectable: ...
         instance_2 = get_instance(SomeInjectable)
         assert instance_1 is instance_2 is not None
 
+    def test_constant_with_recipe(self):
+        class SomeClass: ...
+
+        @constant
+        def recipe() -> SomeClass:
+            return SomeClass()
+
+        instance_1 = get_instance(SomeClass)
+        instance_2 = get_instance(SomeClass)
+        assert instance_1 is instance_2
+        assert isinstance(instance_1, SomeClass)
+
+    async def test_constant_with_async_recipe(self):
+        class SomeClass: ...
+
+        @constant
+        async def recipe() -> SomeClass:
+            return SomeClass()
+
+        with pytest.raises(RuntimeError):
+            get_instance(SomeClass)
+
+        instance_1 = await aget_instance(SomeClass)
+        instance_2 = await aget_instance(SomeClass)
+        assert instance_1 is instance_2
+        assert isinstance(instance_1, SomeClass)
+
     def test_constant_with_on(self):
         class A: ...