Fix provide issue (#514)

docs/main/changelog.rst

@@ -10,6 +10,7 @@ follows `Semantic versioning`_
 
 Develop
 -------
+- Fix a wiring bug with improper resolving of ``Provide[some_provider.provider]``.
 - Fix a typo in ``Factory`` provider docs ``service.add_attributes(clent=client)``
   `#499 <https://github.com/ets-labs/python-dependency-injector/issues/499>`_.
   Thanks to `@rajanjha786 <https://github.com/rajanjha786>`_ for the contribution.

docs/wiring.rst

@@ -39,19 +39,29 @@ a function or method argument:
 
 Specifying an annotation is optional.
 
-There are two types of markers:
-
-- ``Provide[foo]`` - call the provider ``foo`` and injects the result
-- ``Provider[foo]`` - injects the provider ``foo`` itself
+To inject the provider itself use ``Provide[foo.provider]``:
 
 .. code-block:: python
 
+   from dependency_injector.providers import Factory
+   from dependency_injector.wiring import inject, Provide
+
+
+   @inject
+   def foo(bar_provider: Factory[Bar] = Provide[Container.bar.provider]):
+       bar = bar_provider(argument="baz")
+       ...
+You can also use ``Provider[foo]`` for injecting the provider itself:
+
+.. code-block:: python
+
+   from dependency_injector.providers import Factory
    from dependency_injector.wiring import inject, Provider
 
 
    @inject
-   def foo(bar_provider: Callable[..., Bar] = Provider[Container.bar]):
-       bar = bar_provider()
+   def foo(bar_provider: Factory[Bar] = Provider[Container.bar]):
+       bar = bar_provider(argument="baz")
        ...
 
 You can use configuration, provided instance and sub-container providers as you normally do.

src/dependency_injector/wiring.py

@@ -226,7 +226,10 @@ class ProvidersMap:
             self,
             original: providers.Delegate,
     ) -> Optional[providers.Provider]:
-        return self._resolve_provider(original.provides)
+        provider = self._resolve_provider(original.provides)
+        if provider:
+            provider = provider.provider
+        return provider
 
     def _resolve_config_option(
             self,
@@ -539,6 +542,9 @@ def _bind_injections(fn: Callable[..., Any], providers_map: ProvidersMap) -> Non
         if isinstance(marker, Provide):
             fn.__injections__[injection] = provider
         elif isinstance(marker, Provider):
+            if isinstance(provider, providers.Delegate):
+                fn.__injections__[injection] = provider
+            else:
                 fn.__injections__[injection] = provider.provider
 
         if injection in fn.__reference_closing__:

tests/unit/samples/wiringsamples/module.py

@@ -84,7 +84,13 @@ def test_config_value_required_undefined(
 
 
 @inject
-def test_provide_provider(service_provider: Callable[..., Service] = Provider[Container.service.provider]):
+def test_provide_provider(service_provider: Callable[..., Service] = Provide[Container.service.provider]):
+    service = service_provider()
+    return service
+
+
+@inject
+def test_provider_provider(service_provider: Callable[..., Service] = Provider[Container.service.provider]):
     service = service_provider()
     return service
 

tests/unit/wiring/test_wiring_py36.py

@@ -169,6 +169,10 @@ class WiringTest(unittest.TestCase):
         service = module.test_provide_provider()
         self.assertIsInstance(service, Service)
 
+    def test_provider_provider(self):
+        service = module.test_provider_provider()
+        self.assertIsInstance(service, Service)
+
     def test_provided_instance(self):
         class TestService:
             foo = {