Clean up Container provider and add tests

src/dependency_injector/providers.pyi

@@ -370,10 +370,11 @@ class Container(Provider[T]):
     def __getattr__(self, name: str) -> Provider: ...
     @property
     def container(self) -> T: ...
+    def resolve_provider_name(self, provider: Provider) -> str: ...
     @property
-    def parent_name(self) -> str: ...
+    def parent(self) -> Optional[ProviderParent]: ...
     @property
-    def parent(self) -> ProviderParent: ...
+    def parent_name(self) -> Optional[str]: ...
     def assign_parent(self, parent: ProviderParent) -> None: ...
 
 

src/dependency_injector/providers.pyx

@@ -3553,13 +3553,7 @@ cdef class Container(Provider):
         copied.__overriding_providers = deepcopy(self.__overriding_providers, memo)
         copied.apply_overridings()
 
-        # TODO: remove duplication
-        copied_parent = (
-            deepcopy(self.__parent, memo)
-            if is_provider(self.parent) or is_container_instance(self.parent)
-            else self.parent
-        )
-        copied.assign_parent(copied_parent)
+        self._copy_parent(copied, memo)
 
         return copied
 
@@ -3596,24 +3590,43 @@ cdef class Container(Provider):
         self.__container.override_providers(**self.__overriding_providers)
 
     @property
-    def parent_name(self):
-        """Return parent name."""
-        return f'{self.parent.parent_name}.{self.parent.resolve_provider_name(self)}'
+    def related(self):
+        """Return related providers generator."""
+        yield from self.providers.values()
+        yield from super().related
+
+    def resolve_provider_name(self, provider):
+        """Try to resolve provider name."""
+        for provider_name, container_provider in self.providers.items():
+            if container_provider is provider:
+                return provider_name
+        else:
+            raise Error(f'Can not resolve name for provider "{provider}"')
 
     @property
     def parent(self):
         """Return parent."""
         return self.__parent
 
+    @property
+    def parent_name(self):
+        """Return parent name."""
+        if not self.__parent:
+            return None
+
+        name = ''
+        if self.__parent.parent_name:
+            name += f'{self.__parent.parent_name}.'
+        name += f'{self.__parent.resolve_provider_name(self)}'
+
+        return name
+
     def assign_parent(self, parent):
         """Assign parent."""
         self.__parent = parent
 
-    @property
-    def related(self):
-        """Return related providers generator."""
-        yield from self.providers.values()
-        yield from super().related
+    def _copy_parent(self, copied, memo):
+        _copy_parent(self, copied, memo)
 
     cpdef object _provide(self, tuple args, dict kwargs):
         """Return single instance."""

tests/unit/providers/test_base_py2_py3.py

@@ -698,8 +698,6 @@ class DependenciesContainerTests(unittest.TestCase):
         self.assertEqual(container.resolve_provider_name(container.name), 'name')
 
     def test_resolve_provider_name_no_provider(self):
-        provider = providers.Dependency()
         container = providers.DependenciesContainer()
-
         with self.assertRaises(errors.Error):
-            container.resolve_provider_name(provider)
+            container.resolve_provider_name(providers.Provider())

tests/unit/providers/test_container_py2_py3.py

@@ -175,3 +175,50 @@ class ContainerTests(unittest.TestCase):
         b = B(d=D())
         result = b.a().c().bar()
         self.assertEqual(result, 'foo++')
+
+    def test_assign_parent(self):
+        parent = providers.DependenciesContainer()
+        provider = providers.Container(TestCore)
+
+        provider.assign_parent(parent)
+
+        self.assertIs(provider.parent, parent)
+
+    def test_parent_name(self):
+        container = containers.DynamicContainer()
+        provider = providers.Container(TestCore)
+        container.name = provider
+        self.assertEqual(provider.parent_name, 'name')
+
+    def test_parent_name_with_deep_parenting(self):
+        provider = providers.Container(TestCore)
+        container = providers.DependenciesContainer(name=provider)
+        _ = providers.DependenciesContainer(container=container)
+        self.assertEqual(provider.parent_name, 'container.name')
+
+    def test_parent_name_is_none(self):
+        provider = providers.Container(TestCore)
+        self.assertIsNone(provider.parent_name)
+
+    def test_parent_deepcopy(self):
+        container = containers.DynamicContainer()
+        provider = providers.Container(TestCore)
+        container.name = provider
+
+        copied = providers.deepcopy(container)
+
+        self.assertIs(container.name.parent, container)
+        self.assertIs(copied.name.parent, copied)
+
+        self.assertIsNot(container, copied)
+        self.assertIsNot(container.name, copied.name)
+        self.assertIsNot(container.name.parent, copied.name.parent)
+
+    def test_resolve_provider_name(self):
+        container = providers.Container(TestCore)
+        self.assertEqual(container.resolve_provider_name(container.value_getter), 'value_getter')
+
+    def test_resolve_provider_name_no_provider(self):
+        container = providers.Container(TestCore)
+        with self.assertRaises(errors.Error):
+            container.resolve_provider_name(providers.Provider())