Merge branch 'release/4.21.0' into master

Author: rmk135

docs/main/changelog.rst

@@ -7,6 +7,11 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+4.21.0
+------
+- Improve ``Dependency`` provider error message: when dependency is undefined,
+  error message contains its name.
+
 4.20.2
 ------
 - Move docs on container "self" injections to "Providers" section.

docs/providers/dependency.rst

@@ -15,7 +15,12 @@ Dependency provider will control that returned object is an instance of ``instan
 
 To provide a dependency you need to override the ``Dependency`` provider. You can call
 provider ``.override()`` method or provide an overriding provider when creating a container.
-See :ref:`provider-overriding`.
+See :ref:`provider-overriding`. If you don't provide a dependency, ``Dependency`` provider
+will raise an error:
+
+.. literalinclude:: ../../examples/providers/dependency_undefined_error.py
+   :language: python
+   :lines: 18-
 
 You also can provide a default for the dependency. To provide a default use ``default`` argument:
 ``Dependency(..., default=...)``. Default can be a value or a provider. If default is not a provider,

examples/providers/dependency.py

@@ -3,7 +3,7 @@
 import abc
 import dataclasses
 
-from dependency_injector import containers, providers, errors
+from dependency_injector import containers, providers
 
 
 class DbAdapter(metaclass=abc.ABCMeta):
@@ -41,10 +41,5 @@ class Container(containers.DeclarativeContainer):
     assert isinstance(container2.user_service().database, PostgresDbAdapter)
 
     container3 = Container(database=providers.Singleton(object))
-    try:
-        container3.user_service()
-    except errors.Error as exception:
-        print(exception)
-        # The output is:
-        # <object object at 0x107ce5c40> is not an
-        # instance of <class '__main__.DbAdapter'>
+    container3.user_service()  # <-- raises error:
+    # <object ...> is not an instance of DbAdapter

examples/providers/dependency_undefined_error.py

@@ -0,0 +1,31 @@
+"""`Dependency` provider undefined error example."""
+
+import abc
+import dataclasses
+
+from dependency_injector import containers, providers
+
+
+class DbAdapter(metaclass=abc.ABCMeta):
+    ...
+
+
+@dataclasses.dataclass
+class UserService:
+    database: DbAdapter
+
+
+class Container(containers.DeclarativeContainer):
+
+    database = providers.Dependency(instance_of=DbAdapter)
+
+    user_service = providers.Factory(
+        UserService,
+        database=database,
+    )
+
+
+if __name__ == '__main__':
+    container = Container()
+    container.user_service()  # <-- raises error:
+    # Dependency "Container.database" is not defined

src/dependency_injector/__init__.py

@@ -1,6 +1,6 @@
 """Top-level package."""
 
-__version__ = '4.20.2'
+__version__ = '4.21.0'
 """Version number.
 
 :type: str

src/dependency_injector/containers.c

@@ -8,12 +8,13 @@ from typing import (
     ClassVar,
     Callable as _Callable,
     Iterable,
+    Iterator,
     TypeVar,
     Awaitable,
     overload,
 )
 
-from .providers import Provider, Self
+from .providers import Provider, Self, ProviderParent
 
 
 C_Base = TypeVar('C_Base', bound='Container')
@@ -38,18 +39,27 @@ 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: ...
     @overload
-    def traverse(self, types: Optional[Iterable[Type[TT]]] = None) -> _Iterator[TT]: ...
+    def resolve_provider_name(self, provider: Provider) -> str: ...
     @classmethod
     @overload
-    def traverse(self, types: Optional[Iterable[Type[TT]]] = None) -> _Iterator[TT]: ...
+    def resolve_provider_name(cls, provider: Provider) -> str: ...
+    @property
+    def parent(self) -> Optional[ProviderParent]: ...
+    @property
+    def parent_name(self) -> Optional[str]: ...
+    def assign_parent(self, parent: ProviderParent) -> None: ...
+    @overload
+    def traverse(self, types: Optional[Iterable[Type[TT]]] = None) -> Iterator[TT]: ...
+    @classmethod
+    @overload
+    def traverse(cls, types: Optional[Iterable[Type[TT]]] = None) -> Iterator[TT]: ...
 
 
 class DynamicContainer(Container): ...

src/dependency_injector/containers.pyi

@@ -66,6 +66,7 @@ class DynamicContainer(Container):
         self.provider_type = providers.Provider
         self.providers = {}
         self.overridden = tuple()
+        self.parent = None
         self.declarative_parent = None
         self.wired_to_modules = []
         self.wired_to_packages = []
@@ -92,6 +93,8 @@ class DynamicContainer(Container):
         for name, provider in providers.deepcopy(self.providers, memo).items():
             copied.set_provider(name, provider)
 
+        copied.parent = providers.deepcopy(self.parent, memo)
+
         return copied
 
     def __setattr__(self, str name, object value):
@@ -108,9 +111,16 @@ class DynamicContainer(Container):
 
         :rtype: None
         """
-        if isinstance(value, providers.Provider) and not isinstance(value, providers.Self):
+        if isinstance(value, providers.Provider) \
+                and not isinstance(value, providers.Self) \
+                and name != 'parent':
             _check_provider_type(self, value)
+
             self.providers[name] = value
+
+            if isinstance(value, providers.CHILD_PROVIDERS):
+                value.assign_parent(self)
+
         super(DynamicContainer, self).__setattr__(name, value)
 
     def __delattr__(self, str name):
@@ -295,6 +305,29 @@ class DynamicContainer(Container):
         for provider in self.traverse(types=[providers.BaseSingleton]):
             provider.reset()
 
+    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 errors.Error(f'Can not resolve name for provider "{provider}"')
+
+    @property
+    def parent_name(self):
+        """Return parent name."""
+        if self.parent:
+            return self.parent.parent_name
+
+        if self.declarative_parent:
+            return self.declarative_parent.__name__
+
+        return None
+
+    def assign_parent(self, parent):
+        """Assign parent."""
+        self.parent = parent
+
 
 class DeclarativeContainerMetaClass(type):
     """Declarative inversion of control container meta class."""
@@ -341,6 +374,10 @@ class DeclarativeContainerMetaClass(type):
         for provider in six.itervalues(cls.providers):
             _check_provider_type(cls, provider)
 
+        for provider in six.itervalues(cls.cls_providers):
+            if isinstance(provider, providers.CHILD_PROVIDERS):
+                provider.assign_parent(cls)
+
         return cls
 
     def __setattr__(cls, str name, object value):
@@ -359,6 +396,10 @@ class DeclarativeContainerMetaClass(type):
         """
         if isinstance(value, providers.Provider) and name != '__self__':
             _check_provider_type(cls, value)
+
+            if isinstance(value, providers.CHILD_PROVIDERS):
+                value.assign_parent(cls)
+
             cls.providers[name] = value
             cls.cls_providers[name] = value
         super(DeclarativeContainerMetaClass, cls).__setattr__(name, value)
@@ -399,6 +440,19 @@ class DeclarativeContainerMetaClass(type):
         """Return providers traversal generator."""
         yield from providers.traverse(*cls.providers.values(), types=types)
 
+    def resolve_provider_name(cls, provider):
+        """Try to resolve provider name."""
+        for provider_name, container_provider in cls.providers.items():
+            if container_provider is provider:
+                return provider_name
+        else:
+            raise errors.Error(f'Can not resolve name for provider "{provider}"')
+
+    @property
+    def parent_name(cls):
+        """Return parent name."""
+        return cls.__name__
+
     @staticmethod
     def __fetch_self(attributes):
         self = None