Remove generic meta class from resource and async resource classes

.coveragerc

@@ -3,5 +3,8 @@ source = src/dependency_injector
 omit = tests/unit
 plugins = Cython.Coverage
 
+[report]
+show_missing = true
+
 [html]
 directory=reports/unittests/

docs/main/changelog.rst

@@ -13,6 +13,10 @@ follows `Semantic versioning`_
  See issue `#477 <https://github.com/ets-labs/python-dependency-injector/issues/477>`_.
  Thanks to `Andrey Torsunov @gtors <https://github.com/gtors>`_ for reporting the issue.
 - Fix typing stub for ``container.override_providers()`` to accept other types besides ``Provider``.
+- Fix runtime issue with generic typing in resource initializer classes ``resources.Resource``
+ and ``resources.AsyncResource``.
+ See issue `#488 <https://github.com/ets-labs/python-dependency-injector/issues/488>`_.
+ Thanks to `@EdwardBlair <https://github.com/EdwardBlair>`_ for reporting the issue.
 
 4.35.2
 ------

src/dependency_injector/resources.py

@@ -1,26 +1,13 @@
 """Resources module."""
 
 import abc
-import sys
 from typing import TypeVar, Generic
 
-if sys.version_info < (3, 7):
- from typing import GenericMeta
-else:
- class GenericMeta(type):
- ...
-
 
 T = TypeVar('T')
 
 
-class ResourceMeta(GenericMeta, abc.ABCMeta):
- def __getitem__(cls, item):
- # Spike for Python 3.6
- return cls(item)
-
-
-class Resource(Generic[T], metaclass=ResourceMeta):
+class Resource(Generic[T]):
 
  @abc.abstractmethod
  def init(self, *args, **kwargs) -> T:
@@ -31,7 +18,7 @@ def shutdown(self, resource: T) -> None:
  ...
 
 
-class AsyncResource(Generic[T], metaclass=ResourceMeta):
+class AsyncResource(Generic[T]):
 
  @abc.abstractmethod
  async def init(self, *args, **kwargs) -> T:

tests/unit/providers/test_resource_py35.py

@@ -1,8 +1,8 @@
 """Dependency injector resource provider unit tests."""
 
 import asyncio
-
 import unittest
+from typing import Any
 
 from dependency_injector import containers, providers, resources, errors
 
@@ -603,3 +603,31 @@ async def _init():
 
  self.assertIs(result2, resource)
  self.assertEqual(_init.counter, 1)
+
+
+class ResourceTypingTest(unittest.TestCase):
+ # See issue: https://github.com/ets-labs/python-dependency-injector/issues/488
+
+ def test_sync_generic_type(self):
+ class MyDependency:
+ ...
+
+ class MyResource(resources.Resource[MyDependency]):
+ def init(self, *args: Any, **kwargs: Any) -> MyDependency:
+ return MyDependency()
+
+ def shutdown(self, resource: MyDependency) -> None: ...
+
+ self.assertTrue(issubclass(MyResource, resources.Resource))
+
+ def test_async_generic_type(self):
+ class MyDependency:
+ ...
+
+ class MyAsyncResource(resources.AsyncResource[MyDependency]):
+ async def init(self, *args: Any, **kwargs: Any) -> MyDependency:
+ return MyDependency()
+
+ async def shutdown(self, resource: MyDependency) -> None: ...
+
+ self.assertTrue(issubclass(MyAsyncResource, resources.AsyncResource))