Update declarative container to support custom string types

Author: rmk135

src/dependency_injector/containers.c

@@ -469,14 +469,14 @@ class DeclarativeContainerMetaClass(type):
 
         return cls
 
-    def __setattr__(cls, str name, object value):
+    def __setattr__(cls, name, value):
         """Set class attribute.
 
         If value of attribute is provider, it will be added into providers
         dictionary.
 
         :param name: Attribute's name
-        :type name: str
+        :type name: object
 
         :param value: Attribute's value
         :type value: object
@@ -493,14 +493,14 @@ class DeclarativeContainerMetaClass(type):
             cls.cls_providers[name] = value
         super(DeclarativeContainerMetaClass, cls).__setattr__(name, value)
 
-    def __delattr__(cls, str name):
+    def __delattr__(cls, name):
         """Delete class attribute.
 
         If value of attribute is provider, it will be deleted from providers
         dictionary.
 
         :param name: Attribute's name
-        :type name: str
+        :type name: object
 
         :rtype: None
         """

src/dependency_injector/containers.pyx

@@ -496,3 +496,30 @@ class Container(containers.DeclarativeContainer):
             str(context.exception),
             'Dependency "Container.child_container.dependency" is not defined',
         )
+
+
+class DeclarativeContainerWithCustomStringTests(unittest.TestCase):
+    # See: https://github.com/ets-labs/python-dependency-injector/issues/479
+
+    class CustomString(str):
+        pass
+
+    class CustomClass:
+        thing = None
+
+    class CustomContainer(containers.DeclarativeContainer):
+        pass
+
+    def setUp(self):
+        self.container = self.CustomContainer
+        self.provider = providers.Provider()
+
+    def test_setattr(self):
+        setattr(self.container, self.CustomString('test_attr'), self.provider)
+        self.assertIs(self.container.test_attr, self.provider)
+
+    def test_delattr(self):
+        setattr(self.container, self.CustomString('test_attr'), self.provider)
+        delattr(self.container, self.CustomString('test_attr'))
+        with self.assertRaises(AttributeError):
+            self.container.test_attr

tests/unit/containers/test_declarative_py2_py3.py

@@ -698,7 +698,6 @@ class CustomClass:
         thing = None
 
     def setUp(self):
-        self.object = self.CustomClass()
         self.container = containers.DynamicContainer()
         self.provider = providers.Provider()