Add implementation, tests, and typing stubs

src/dependency_injector/providers.pyi

@@ -267,6 +267,7 @@ class BaseSingleton(Provider[T]):
     def set_attributes(self, **kwargs: Injection) -> BaseSingleton[T]: ...
     def clear_attributes(self) -> BaseSingleton[T]: ...
     def reset(self) -> None: ...
+    def full_reset(self) -> None: ...
 
 
 class Singleton(BaseSingleton[T]): ...

src/dependency_injector/providers.pyx

@@ -2468,6 +2468,15 @@ cdef class BaseSingleton(Provider):
         """
         raise NotImplementedError()
 
+    def full_reset(self):
+        """Reset cached instance in current and all underlying singletons, if any.
+
+        :rtype: None
+        """
+        self.reset()
+        for provider in self.traverse(types=[BaseSingleton]):
+            provider.reset()
+
     @property
     def related(self):
         """Return related providers generator."""

tests/unit/providers/test_singletons_py2_py3.py

@@ -355,6 +355,37 @@ class _BaseSingletonTestCase(object):
 
         self.assertIsNot(instance1, instance2)
 
+    def test_reset_with_singleton(self):
+        dependent_singleton = providers.Singleton(object)
+        provider = self.singleton_cls(dict, dependency=dependent_singleton)
+
+        dependent_instance = dependent_singleton()
+        instance1 = provider()
+        self.assertIs(instance1['dependency'], dependent_instance)
+
+        provider.reset()
+
+        instance2 = provider()
+        self.assertIs(instance1['dependency'], dependent_instance)
+
+        self.assertIsNot(instance1, instance2)
+
+    def test_full_reset(self):
+        dependent_singleton = providers.Singleton(object)
+        provider = self.singleton_cls(dict, dependency=dependent_singleton)
+
+        dependent_instance1 = dependent_singleton()
+        instance1 = provider()
+        self.assertIs(instance1['dependency'], dependent_instance1)
+
+        provider.full_reset()
+
+        dependent_instance2 = dependent_singleton()
+        instance2 = provider()
+        self.assertIsNot(instance2['dependency'], dependent_instance1)
+        self.assertIsNot(dependent_instance1, dependent_instance2)
+        self.assertIsNot(instance1, instance2)
+
 
 class SingletonTests(_BaseSingletonTestCase, unittest.TestCase):