Add prototype for flat resolving

src/dependency_injector/containers.pyi

@@ -38,13 +38,13 @@ class Container:
     def override_providers(self, **overriding_providers: Provider) -> None: ...
     def reset_last_overriding(self) -> None: ...
     def reset_override(self) -> None: ...
-    def resolve_provider_name(self, provider_to_resolve: Provider) -> Optional[str]: ...
     def wire(self, modules: Optional[Iterable[Any]] = None, packages: Optional[Iterable[Any]] = None) -> None: ...
     def unwire(self) -> None: ...
     def init_resources(self) -> Optional[Awaitable]: ...
     def shutdown_resources(self) -> Optional[Awaitable]: ...
     def apply_container_providers_overridings(self) -> None: ...
     def reset_singletons(self) -> None: ...
+    def resolve_provider_name(self, provider: Provider) -> Optional[str]: ...
     @overload
     def traverse(self, types: Optional[Iterable[Type[TT]]] = None) -> _Iterator[TT]: ...
     @classmethod

src/dependency_injector/containers.pyx

@@ -110,7 +110,12 @@ class DynamicContainer(Container):
         """
         if isinstance(value, providers.Provider) and not isinstance(value, providers.Self):
             _check_provider_type(self, value)
+
             self.providers[name] = value
+
+            if isinstance(value, providers.Dependency):
+                value.set_parent(self)
+
         super(DynamicContainer, self).__setattr__(name, value)
 
     def __delattr__(self, str name):
@@ -295,6 +300,15 @@ class DynamicContainer(Container):
         for provider in self.traverse(types=[providers.BaseSingleton]):
             provider.reset()
 
+    def resolve_provider_name(self, provider):
+        """Try to resolve provider name."""
+        # TODO: add tests
+        for provider_name, container_provider in self.providers.items():
+            if container_provider is provider:
+                return provider_name
+        else:
+            raise errors.Error(f'Can not resolve name for provider "{provider}"')
+
 
 class DeclarativeContainerMetaClass(type):
     """Declarative inversion of control container meta class."""
@@ -317,6 +331,8 @@ class DeclarativeContainerMetaClass(type):
             if isinstance(provider, providers.Provider) and not isinstance(provider, providers.Self)
         }
 
+        # TODO: set dependencies parent
+
         inherited_providers = {
             name: provider
             for base in bases
@@ -361,6 +377,7 @@ class DeclarativeContainerMetaClass(type):
             _check_provider_type(cls, value)
             cls.providers[name] = value
             cls.cls_providers[name] = value
+            # TODO: set dependencies parent
         super(DeclarativeContainerMetaClass, cls).__setattr__(name, value)
 
     def __delattr__(cls, str name):

src/dependency_injector/providers.pxd

@@ -41,6 +41,7 @@ cdef class Delegate(Provider):
 cdef class Dependency(Provider):
     cdef object __instance_of
     cdef object __default
+    cdef object __parent
 
 
 cdef class ExternalDependency(Dependency):
@@ -305,6 +306,12 @@ cpdef bint is_delegated(object instance)
 cpdef str represent_provider(object provider, object provides)
 
 
+cpdef bint is_container_instance(object instance)
+
+
+cpdef bint is_container_class(object instance)
+
+
 cpdef object deepcopy(object instance, dict memo=*)
 
 

src/dependency_injector/providers.pyi

@@ -35,6 +35,7 @@ from . import resources
 
 
 Injection = Any
+ProviderParent = Union['Provider', Any]
 T = TypeVar('T')
 TT = TypeVar('TT')
 
@@ -105,6 +106,9 @@ class Dependency(Provider[T]):
     def instance_of(self) -> Type[T]: ...
     @property
     def default(self) -> Provider[T]: ...
+    @property
+    def parent(self) -> ProviderParent: ...
+    def set_parent(self, parent: ProviderParent) -> None: ...
     def provided_by(self, provider: Provider) -> OverridingContext: ...
 
 

src/dependency_injector/providers.pyx

@@ -617,6 +617,8 @@ cdef class Dependency(Provider):
             default = Object(default)
         self.__default = default
 
+        self.__parent = None
+
         super(Dependency, self).__init__()
 
     def __deepcopy__(self, memo):
@@ -625,8 +627,20 @@ cdef class Dependency(Provider):
         if copied is not None:
             return copied
 
-        copied_default = deepcopy(self.__default, memo) if self.__default is not UNDEFINED else UNDEFINED
+        copied_default = (
+            deepcopy(self.__default, memo)
+            if self.__default is not UNDEFINED
+            else UNDEFINED
+        )
+        copied_parent = (
+            deepcopy(self.__parent, memo)
+            if is_provider(self.parent) or is_container_instance(self.parent)
+            else self.parent
+        )
+
         copied = self.__class__(self.__instance_of, copied_default)
+        # TODO: introduce .set_default() for consistency
+        copied.set_parent(copied_parent)
 
         self._copy_overridings(copied, memo)
 
@@ -644,7 +658,7 @@ cdef class Dependency(Provider):
         elif not self.__last_overriding and self.__default is not UNDEFINED:
             result = self.__default(*args, **kwargs)
         else:
-            raise Error('Dependency is not defined')
+            self._raise_undefined_error()
 
         if self.is_async_mode_disabled():
             self._check_instance_type(result)
@@ -697,6 +711,15 @@ cdef class Dependency(Provider):
         """Return default provider."""
         return self.__default
 
+    @property
+    def parent(self):
+        """Return parent."""
+        return self.__parent
+
+    def set_parent(self, parent):
+        """Set parent."""
+        self.__parent = parent
+
     @property
     def related(self):
         """Return related providers generator."""
@@ -727,6 +750,14 @@ cdef class Dependency(Provider):
         if not isinstance(instance, self.instance_of):
             raise Error('{0} is not an instance of {1}'.format(instance, self.instance_of))
 
+    def _raise_undefined_error(self):
+        if is_container_instance(self.parent) and self.parent.declarative_parent is not None:
+            name_in_container = self.parent.resolve_provider_name(self)
+            name = f'{self.parent.declarative_parent.__name__}.{name_in_container}'
+            raise Error(f'Dependency "{name}" is not defined')
+
+        raise Error('Dependency is not defined')
+
 
 cdef class ExternalDependency(Dependency):
     """:py:class:`ExternalDependency` provider describes dependency interface.
@@ -4093,6 +4124,30 @@ cpdef str represent_provider(object provider, object provides):
         address=hex(id(provider)))
 
 
+cpdef bint is_container_instance(object instance):
+    """Check if instance is container instance.
+
+    :param instance: Instance to be checked.
+    :type instance: object
+
+    :rtype: bool
+    """
+    return (not isinstance(instance, CLASS_TYPES) and
+            getattr(instance, '__IS_CONTAINER__', False) is True)
+
+
+cpdef bint is_container_class(object instance):
+    """Check if instance is container class.
+
+    :param instance: Instance to be checked.
+    :type instance: object
+
+    :rtype: bool
+    """
+    return (isinstance(instance, CLASS_TYPES) and
+            getattr(instance, '__IS_CONTAINER__', False) is True)
+
+
 cpdef object deepcopy(object instance, dict memo=None):
     """Return full copy of provider or container with providers."""
     if memo is None:
@@ -4102,6 +4157,7 @@ cpdef object deepcopy(object instance, dict memo=None):
 
     return copy.deepcopy(instance, memo)
 
+
 def __add_sys_streams(memo):
     """Add system streams to memo dictionary.