Fix a Python 3.9 GenericAlias introspection bug, issue #362

docs/main/changelog.rst

@@ -7,6 +7,14 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+Development version
+-------------------
+- Fix a Python 3.9 specific bug in ``wiring`` module: introspection doesn't work for
+  builtin ``types.GenericAlias``. This resulted in wiring failure for modules
+  importing ``queue.Queue``.
+  See issue `#362 <https://github.com/ets-labs/python-dependency-injector/issues/362>`_.
+  Thanks `@ventaquil <https://github.com/ventaquil>`_ for the bug report.
+
 4.10.0
 ------
 - Add ``strict`` mode and ``required`` modifier for ``Configuration`` provider.

src/dependency_injector/wiring.py

@@ -28,6 +28,12 @@ else:
     class GenericMeta(type):
         ...
 
+# Hotfix, see: https://github.com/ets-labs/python-dependency-injector/issues/362
+if sys.version_info >= (3, 9):
+    from types import GenericAlias
+else:
+    GenericAlias = None
+
 
 try:
     from fastapi.params import Depends as FastAPIDepends
@@ -333,6 +339,10 @@ def _unpatch(
 def _fetch_reference_injections(
         fn: Callable[..., Any],
 ) -> Tuple[Dict[str, Any], Dict[str, Any]]:
+    # # Hotfix, see: https://github.com/ets-labs/python-dependency-injector/issues/362
+    if GenericAlias and fn is GenericAlias:
+        fn = fn.__init__
+
     signature = inspect.signature(fn)
 
     injections = {}

tests/unit/samples/wiringsamples/queuemodule.py

@@ -0,0 +1,5 @@
+# Hotfix, see: https://github.com/ets-labs/python-dependency-injector/issues/362
+from queue import Queue
+
+
+__all__ = ('Queue',)

tests/unit/wiring/test_wiring_py36.py

@@ -263,6 +263,21 @@ class WiringTest(unittest.TestCase):
         self.assertIsInstance(service, Service)
 
 
+class WiringAndQueue(unittest.TestCase):
+
+    def test_wire_queue(self) -> None:
+        from wiringsamples import queuemodule
+        container = Container()
+        self.addCleanup(container.unwire)
+
+        # Should not raise exception
+        # See: https://github.com/ets-labs/python-dependency-injector/issues/362
+        try:
+            container.wire(modules=[queuemodule])
+        except:
+            raise
+
+
 class WiringAndFastAPITest(unittest.TestCase):
 
     container: Container