235 Fix Delegate cannot be used in overridden container (#236)

* Add test for bug #235

* Fix issue + refactoring

* Update changelog

docs/main/changelog.rst

@@ -7,6 +7,13 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+Development version
+-------------------
++ Fix ``3.14.11`` degradation issue causing inability of using ``Delegate`` provider in
+  ``DeclarativeContainer`` when this container is instantiated with overriding of delegating
+  provider (thanks to `GitterRemote <https://github .com/GitterRemote>`_, issue details are
+  `here <https://github.com/ets-labs/python-dependency-injector/issues/235>`_).
+
 3.14.11
 -------
 + Fix issue causing creation of a copy of provided object by ``Object`` provider when it was a

src/dependency_injector/providers.pxd

@@ -21,8 +21,10 @@ cdef class Object(Provider):
     cpdef object _provide(self, tuple args, dict kwargs)
 
 
-cdef class Delegate(Object):
-    pass
+cdef class Delegate(Provider):
+    cdef object __provides
+
+    cpdef object _provide(self, tuple args, dict kwargs)
 
 
 cdef class Dependency(Provider):

src/dependency_injector/providers.pyx

@@ -291,7 +291,7 @@ cdef class Object(Provider):
         return self.__provides
 
 
-cdef class Delegate(Object):
+cdef class Delegate(Provider):
     """Delegate provider returns provider "as is".
 
     .. py:attribute:: provides
@@ -305,9 +305,49 @@ cdef class Delegate(Object):
         """Initializer.
 
         :param provides: Value that have to be provided.
-        :type provides: object
+        :type provides: :py:class:`Provider`
         """
-        super(Delegate, self).__init__(ensure_is_provider(provides))
+        self.__provides = ensure_is_provider(provides)
+        super(Delegate, self).__init__()
+
+    def __deepcopy__(self, memo):
+        """Create and return full copy of provider."""
+        copied = memo.get(id(self))
+        if copied is not None:
+            return copied
+
+        copied = self.__class__(deepcopy(self.__provides, memo))
+
+        self._copy_overridings(copied, memo)
+
+        return copied
+
+    def __str__(self):
+        """Return string representation of provider.
+
+        :rtype: str
+        """
+        return represent_provider(provider=self, provides=self.__provides)
+
+    def __repr__(self):
+        """Return string representation of provider.
+
+        :rtype: str
+        """
+        return self.__str__()
+
+    cpdef object _provide(self, tuple args, dict kwargs):
+        """Return provided instance.
+
+        :param args: Tuple of context positional arguments.
+        :type args: tuple[object]
+
+        :param kwargs: Dictionary of context keyword arguments.
+        :type kwargs: dict[str, object]
+
+        :rtype: object
+        """
+        return self.__provides
 
 
 cdef class Dependency(Provider):
@@ -834,7 +874,7 @@ cdef class CallableDelegate(Delegate):
         if isinstance(callable, Callable) is False:
             raise Error('{0} can wrap only {1} providers'.format(
                 self.__class__, Callable))
-        super(Delegate, self).__init__(callable)
+        super(CallableDelegate, self).__init__(callable)
 
 
 cdef class Coroutine(Callable):
@@ -1416,7 +1456,7 @@ cdef class FactoryDelegate(Delegate):
         if isinstance(factory, Factory) is False:
             raise Error('{0} can wrap only {1} providers'.format(
                 self.__class__, Factory))
-        super(Delegate, self).__init__(factory)
+        super(FactoryDelegate, self).__init__(factory)
 
 
 cdef class FactoryAggregate(Provider):
@@ -1923,7 +1963,7 @@ cdef class SingletonDelegate(Delegate):
         if isinstance(singleton, BaseSingleton) is False:
             raise Error('{0} can wrap only {1} providers'.format(
                 self.__class__, BaseSingleton))
-        super(Delegate, self).__init__(singleton)
+        super(SingletonDelegate, self).__init__(singleton)
 
 
 cdef class Injection(object):

tests/unit/containers/test_declarative_py2_py3.py

@@ -1,5 +1,6 @@
 """Dependency injector declarative container unit tests."""
 
+import collections
 import unittest2 as unittest
 
 from dependency_injector import (
@@ -313,3 +314,19 @@ class DeclarativeContainerTests(unittest.TestCase):
         self.assertIs(container.p2.cls, container.p1)
         self.assertIs(_Container.p2.cls, _Container.p1)
         self.assertIsNot(container.p2.cls,  _Container.p1)
+
+    def test_init_with_dependency_delegation(self):
+        # Bug:
+        # https://github.com/ets-labs/python-dependency-injector/issues/235
+        A = collections.namedtuple('A', [])
+        B = collections.namedtuple('B', ['fa'])
+        C = collections.namedtuple('B', ['a'])
+
+        class Services(containers.DeclarativeContainer):
+            a = providers.Dependency()
+            c = providers.Factory(C, a=a)
+            b = providers.Factory(B, fa=a.delegate())
+
+        a = providers.Factory(A)
+        assert isinstance(Services(a=a).c().a, A)  # ok
+        Services(a=a).b().fa()