Add tests and implement cache reset for configuration option

src/dependency_injector/providers.pyx

@@ -1489,8 +1489,13 @@ cdef class ConfigurationOption(Provider):
 
     def reset_cache(self):
         self.__cache = UNDEFINED
-        for child in self.__children.values():
-            child.reset_cache()
+
+        for provider in self.__children.values():
+            provider.reset_cache()
+
+        for provider in self.overrides:
+            if isinstance(provider, (Configuration, ConfigurationOption)):
+                provider.reset_cache()
 
     def update(self, value):
         """Set configuration options.

tests/unit/providers/test_configuration_py2_py3.py

@@ -416,6 +416,58 @@ class ConfigLinkingTests(unittest.TestCase):
         self.assertEqual(services.config.value(), 'services2')
         self.assertEqual(services.value_getter(), 'services2')
 
+    def test_reset_overriding_cache(self):
+        class Core(containers.DeclarativeContainer):
+            config = providers.Configuration()
+
+            greetings = providers.Factory(str, config.greeting)
+
+        class Application(containers.DeclarativeContainer):
+            config = providers.Configuration()
+
+            core = providers.Container(
+                Core,
+                config=config,
+            )
+
+            greetings = providers.Factory(str, config.greeting)
+
+        container = Application()
+
+        container.config.set('greeting', 'Hello World')
+        self.assertEqual(container.greetings(), 'Hello World')
+        self.assertEqual(container.core.greetings(), 'Hello World')
+
+        container.config.set('greeting', 'Hello Bob')
+        self.assertEqual(container.greetings(), 'Hello Bob')
+        self.assertEqual(container.core.greetings(), 'Hello Bob')
+
+    def test_reset_overriding_cache_for_option(self):
+        class Core(containers.DeclarativeContainer):
+            config = providers.Configuration()
+
+            greetings = providers.Factory(str, config.greeting)
+
+        class Application(containers.DeclarativeContainer):
+            config = providers.Configuration()
+
+            core = providers.Container(
+                Core,
+                config=config.option,
+            )
+
+            greetings = providers.Factory(str, config.option.greeting)
+
+        container = Application()
+
+        container.config.set('option.greeting', 'Hello World')
+        self.assertEqual(container.greetings(), 'Hello World')
+        self.assertEqual(container.core.greetings(), 'Hello World')
+
+        container.config.set('option.greeting', 'Hello Bob')
+        self.assertEqual(container.greetings(), 'Hello Bob')
+        self.assertEqual(container.core.greetings(), 'Hello Bob')
+
 
 class ConfigFromIniTests(unittest.TestCase):