Add singleton stubs

src/dependency_injector/providers.pyi

@@ -196,6 +196,37 @@ class FactoryAggregate(Provider):
     def factories(self) -> Dict[str, Factory]: ...
 
 
+class BaseSingleton(Provider, Generic[T]):
+    provided_type = Optional[Type]
+    def __init__(self, provides: _Callable[..., T], *args: Injection, **kwargs: Injection) -> None: ...
+    @property
+    def cls(self) -> T: ...
+    @property
+    def provided(self) -> ProvidedInstance: ...
+    @property
+    def args(self) -> Tuple[Injection]: ...
+    def add_args(self, *args: Injection) -> Factory[T]: ...
+    def set_args(self, *args: Injection) -> Factory[T]: ...
+    def clear_args(self) -> Factory[T]: ...
+    @property
+    def kwargs(self) -> Dict[str, Injection]: ...
+    def add_kwargs(self, **kwargs: Injection) -> Factory[T]: ...
+    def set_kwargs(self, **kwargs: Injection) -> Factory[T]: ...
+    def clear_kwargs(self) -> Factory[T]: ...
+    @property
+    def attributes(self) -> Dict[str, Injection]: ...
+    def add_attributes(self, **kwargs: Injection) -> Factory[T]: ...
+    def set_attributes(self, **kwargs: Injection) -> Factory[T]: ...
+    def clear_attributes(self) -> Factory[T]: ...
+    def reset(self) -> None: ...
+
+
+class Singleton(BaseSingleton): ...
+
+
+class DelegatedSingleton(Singleton): ...
+
+
 class ProvidedInstanceFluentInterface:
     def __getattr__(self, item: str) -> AttributeGetter: ...
     def __getitem__(self, item: str) -> ItemGetter: ...

tests/typing/singleton.py

@@ -0,0 +1,64 @@
+from typing import Tuple, Any, Dict
+
+from dependency_injector import providers
+
+
+class Animal:
+    ...
+
+
+class Cat(Animal):
+
+    def __init__(self, *_, **__): ...
+
+    @classmethod
+    def create(cls) -> Animal:
+        return cls()
+
+
+# Test 1: to check the return type (class)
+provider1 = providers.Singleton(Cat)
+animal1: Animal = provider1(1, 2, 3, b='1', c=2, e=0.0)
+
+# Test 2: to check the return type (class factory method)
+provider2 = providers.Singleton(Cat.create)
+animal2: Animal = provider2()
+
+# Test 3: to check the .override() method
+provider3 = providers.Singleton(Animal)
+with provider3.override(providers.Singleton(Cat)):
+    provider3()
+
+# Test 4: to check the .args, .kwargs, .attributes attributes
+provider4 = providers.Singleton(Animal)
+args4: Tuple[Any] = provider4.args
+kwargs4: Dict[str, Any] = provider4.kwargs
+attributes4: Dict[str, Any] = provider4.attributes
+
+# Test 5: to check the provided instance interface
+provider5 = providers.Singleton(Animal)
+provided5: providers.ProvidedInstance = provider5.provided
+attr_getter5: providers.AttributeGetter = provider5.provided.attr
+item_getter5: providers.ItemGetter = provider5.provided['item']
+method_caller5: providers.MethodCaller = provider5.provided.method.call(123, arg=324)
+
+# Test 6: to check the DelegatedFactory
+provider6 = providers.DelegatedSingleton(Cat)
+animal6: Animal = provider6(1, 2, 3, b='1', c=2, e=0.0)
+
+# # Test 7: to check the AbstractFactory
+# provider7 = providers.AbstractFactory(Animal)
+# provider7.override(providers.Factory(Cat))
+# animal7: Animal = provider7(1, 2, 3, b='1', c=2, e=0.0)
+#
+# # Test 8: to check the FactoryDelegate __init__
+# provider8 = providers.FactoryDelegate(providers.Factory(object))
+#
+# # Test 9: to check FactoryAggregate provider
+# provider9 = providers.FactoryAggregate(
+#     a=providers.Factory(object),
+#     b=providers.Factory(object),
+# )
+# factory_a_9: providers.Factory = provider9.a
+# factory_b_9: providers.Factory = provider9.b
+# val9: Any = provider9('a')