Implement lazy initialization and improve copying for AttributeGetter provider

src/dependency_injector/containers.c

@@ -1402,13 +1402,13 @@ struct __pyx_obj_19dependency_injector_9providers_ProvidedInstance {
  * 
  * 
  * cdef class AttributeGetter(Provider):             # <<<<<<<<<<<<<<
- *     cdef Provider __provider
+ *     cdef object __provides
- *     cdef object __attribute
+ *     cdef object __name
  */
 struct __pyx_obj_19dependency_injector_9providers_AttributeGetter {
   struct __pyx_obj_19dependency_injector_9providers_Provider __pyx_base;
-  struct __pyx_obj_19dependency_injector_9providers_Provider *__pyx___provider;
+  PyObject *__pyx___provides;
-  PyObject *__pyx___attribute;
+  PyObject *__pyx___name;
 };
 
 
@@ -2158,8 +2158,8 @@ static struct __pyx_vtabstruct_19dependency_injector_9providers_ProvidedInstance
  * 
  * 
  * cdef class AttributeGetter(Provider):             # <<<<<<<<<<<<<<
- *     cdef Provider __provider
+ *     cdef object __provides
- *     cdef object __attribute
+ *     cdef object __name
  */
 
 struct __pyx_vtabstruct_19dependency_injector_9providers_AttributeGetter {

src/dependency_injector/providers.pxd

@@ -241,8 +241,8 @@ cdef class ProvidedInstance(Provider):
 
 
 cdef class AttributeGetter(Provider):
-    cdef Provider __provider
+    cdef object __provides
-    cdef object __attribute
+    cdef object __name
 
     cpdef object _provide(self, tuple args, dict kwargs)
 

src/dependency_injector/providers.pyi

@@ -226,7 +226,7 @@ class Configuration(Object[Any]):
     def set_strict(self, strict: bool) -> Configuration: ...
 
     def get_children(self) -> _Dict[str, ConfigurationOption]: ...
-    def set_children(self, children: _Dict[str, ConfigurationOption) -> Configuration: ...
+    def set_children(self, children: _Dict[str, ConfigurationOption]) -> Configuration: ...
 
     def get(self, selector: str) -> Any: ...
     def set(self, selector: str, value: Any) -> OverridingContext[P]: ...
@@ -433,7 +433,10 @@ class ProvidedInstance(Provider, ProvidedInstanceFluentInterface):
 
 
 class AttributeGetter(Provider, ProvidedInstanceFluentInterface):
-    def __init__(self, provider: Provider, attribute: str) -> None: ...
+    def __init__(self, provides: Optional[Provider] = None, attribute: Optional[str] = None) -> None: ...
+    @property
+    def name(self) -> Optional[str]: ...
+    def set_name(self, name: Optional[str]) -> ProvidedInstanceFluentInterface: ...
 
 
 class ItemGetter(Provider, ProvidedInstanceFluentInterface):

src/dependency_injector/providers.pyx

@@ -3894,7 +3894,7 @@ cdef class ProvidedInstance(Provider):
     def __repr__(self):
         return f'{self.__class__.__name__}(\'{self.__provides}\')'
 
-    def __deepcopy__(self, memo=None):
+    def __deepcopy__(self, memo):
         copied = memo.get(id(self))
         if copied is not None:
             return copied
@@ -3939,25 +3939,26 @@ cdef class AttributeGetter(Provider):
     You should not create this provider directly. See :py:class:`ProvidedInstance` instead.
     """
 
-    def __init__(self, provider, attribute):
+    def __init__(self, provides=None, name=None):
-        self.__provider = provider
+        self.__provides = None
-        self.__attribute = attribute
+        self.set_provides(provides)
+
+        self.__name = None
+        self.set_name(name)
         super().__init__()
 
     def __repr__(self):
-        return f'{self.__class__.__name__}(\'{self.__attribute}\')'
+        return f'{self.__class__.__name__}(\'{self.__name}\')'
-
-    def __deepcopy__(self, memo=None):
-        cdef AttributeGetter copied
 
+    def __deepcopy__(self, memo):
         copied = memo.get(id(self))
         if copied is not None:
             return copied
 
-        return self.__class__(
+        copied = _memorized_duplicate(self, memo)
-            deepcopy(self.__provider, memo),
+        copied.set_provides(_copy_if_provider(self.provides, memo))
-            self.__attribute,
+        copied.set_name(self.name)
-        )
+        return copied
 
     def __getattr__(self, item):
         return AttributeGetter(self, item)
@@ -3967,13 +3968,23 @@ cdef class AttributeGetter(Provider):
 
     @property
     def provides(self):
-        """Return provider."""
+        """Return provider's provides."""
-        return self.__provider
+        return self.__provides
+
+    def set_provides(self, provides):
+        """Set provider's provides."""
+        self.__provides = provides
+        return self
 
     @property
     def name(self):
         """Return name of the attribute."""
-        return self.__attribute
+        return self.__name
+
+    def set_name(self, name):
+        """Set name of the attribute."""
+        self.__name = name
+        return self
 
     def call(self, *args, **kwargs):
         return MethodCaller(self, *args, **kwargs)
@@ -3981,22 +3992,23 @@ cdef class AttributeGetter(Provider):
     @property
     def related(self):
         """Return related providers generator."""
-        yield self.__provider
+        if is_provider(self.provides):
+            yield self.provides
         yield from super().related
 
     cpdef object _provide(self, tuple args, dict kwargs):
-        provided = self.__provider(*args, **kwargs)
+        provided = self.provides(*args, **kwargs)
         if __is_future_or_coroutine(provided):
             future_result = asyncio.Future()
             provided = asyncio.ensure_future(provided)
             provided.add_done_callback(functools.partial(self._async_provide, future_result))
             return future_result
-        return getattr(provided, self.__attribute)
+        return getattr(provided, self.name)
 
     def _async_provide(self, future_result, future):
         try:
             provided = future.result()
-            result = getattr(provided, self.__attribute)
+            result = getattr(provided, self.name)
         except Exception:
             pass
         else:

tests/unit/providers/test_provided_instance_py2_py3.py

@@ -69,16 +69,6 @@ class ProvidedInstanceTests(unittest.TestCase):
     def setUp(self):
         self.container = Container()
 
-    def test_lazy_init(self):
-        provides = providers.Object(object())
-        provider = providers.ProvidedInstance()
-        provider.set_provides(provides)
-        self.assertIs(provider.provides, provides)
-
-    def test_set_provides_returns_self(self):
-        provider = providers.ProvidedInstance()
-        self.assertIs(provider.set_provides(providers.Provider()), provider)
-
     def test_is_provider(self):
         self.assertTrue(providers.is_provider(self.container.service.provided))
 
@@ -136,6 +126,26 @@ class ProvidedInstanceTests(unittest.TestCase):
         )
 
 
+class LazyInitTests(unittest.TestCase):
+
+    def test_provided_instance(self):
+        provides = providers.Object(object())
+        provider = providers.ProvidedInstance()
+        provider.set_provides(provides)
+        self.assertIs(provider.provides, provides)
+        self.assertIs(provider.set_provides(providers.Provider()), provider)
+
+    def test_attribute_getter(self):
+        provides = providers.Object(object())
+        provider = providers.AttributeGetter()
+        provider.set_provides(provides)
+        provider.set_name('__dict__')
+        self.assertIs(provider.provides, provides)
+        self.assertEqual(provider.name, '__dict__')
+        self.assertIs(provider.set_provides(providers.Provider()), provider)
+        self.assertIs(provider.set_name('__dict__'), provider)
+
+
 class ProvidedInstancePuzzleTests(unittest.TestCase):
 
     def test_puzzled(self):