Fix #368 Async providers do not work with async dependencies

docs/main/changelog.rst

@@ -7,6 +7,12 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+4.10.4
+------
+- Fix a bug with asynchronous injections: async providers do not work with async dependencies.
+  See issue: `#368 <https://github.com/ets-labs/python-dependency-injector/issues/368>`_.
+  Thanks `@kolypto <https://github.com/kolypto>`_ for the bug report.
+
 4.10.3
 ------
 - Fix a bug in the ``Configuration`` provider: strict mode didn't work when provider

src/dependency_injector/providers.pxd

@@ -5,6 +5,7 @@ try:
 except ImportError:
     asyncio = None
 
+import functools
 import inspect
 
 cimport cython
@@ -531,9 +532,19 @@ cdef inline object __call(
 cdef inline void __async_call_callback(object future):
     (future_result, call), args, kwargs = future.result()
     result = call(*args, **kwargs)
+
+    if __isawaitable(result):
+        result = asyncio.ensure_future(result)
+        result.add_done_callback(functools.partial(__async_result_callback, future_result))
+        return
+
     future_result.set_result(result)
 
 
+cdef inline object __async_result_callback(object future_result, object future):
+    future_result.set_result(future.result())
+
+
 cdef inline object __callable_call(Callable self, tuple args, dict kwargs):
     return __call(
         self.__provides,

tests/unit/providers/test_async_py36.py

@@ -816,3 +816,24 @@ class AsyncTypingStubTests(AsyncTestCase):
         self.assertIs(service2.client.resource2, RESOURCE2)
 
         self.assertIsNot(service1.client, service2.client)
+
+
+class AsyncProvidersWithAsyncDependenciesTests(AsyncTestCase):
+
+    def test_injections(self):
+        # See: https://github.com/ets-labs/python-dependency-injector/issues/368
+        async def async_db_provider():
+            return {'db': 'ok'}
+
+        async def async_service(db=None):
+            return {'service': 'ok', 'db': db}
+
+        class Container(containers.DeclarativeContainer):
+
+            db = providers.Factory(async_db_provider)
+            service = providers.Singleton(async_service, db=db)
+
+        container = Container()
+        service = self._run(container.service())
+
+        self.assertEquals(service, {'service': 'ok', 'db': {'db': 'ok'}})