fix: resolve __init__ introspection when Protocol is first in bases

Protocol's `_no_init_or_replace_init` stub shadows real `__init__` from
base classes. Walk MRO to find the actual `__init__` with type hints.

Closes #628

Author: fadedDexofan

src/dishka/provider/make_factory.py

@@ -92,8 +92,22 @@ def _is_bound_method(obj: Any) -> bool:
     return ismethod(obj) and bool(obj.__self__)
 
 
+def _resolve_init(tp: type) -> Any:
+    init = tp.__init__  # type: ignore[misc]
+    if init is not _protocol_init:
+        return init
+    for cls in tp.__mro__:
+        if cls is object:
+            continue
+        init_candidate = cls.__dict__.get("__init__")
+        if init_candidate is not None and init_candidate is not _protocol_init:
+            return init_candidate
+    return init
+
+
 def _get_init_members(tp: type) -> MembersStorage[str, None]:
-    type_hints = get_all_type_hints(tp.__init__)  # type: ignore[misc, no-untyped-call]
+    real_init = _resolve_init(tp)
+    type_hints = get_all_type_hints(real_init)  # type: ignore[no-untyped-call]
     if "__init__" in tp.__dict__:
         overridden = frozenset(type_hints)
     else:
@@ -256,7 +270,7 @@ def _make_factory_by_class(
     if not provides:
         provides = source
 
-    init = strip_alias(source).__init__
+    init = _resolve_init(strip_alias(source))
     if missing_hints := _params_without_hints(init, skip_self=True):
         raise MissingHintsError(source, missing_hints, append_init=True)
     # we need to fix concrete generics and normal classes as well

tests/unit/container/test_with_parents.py

@@ -303,3 +303,32 @@ class MyProvider(Provider):
     container = make_container(MyProvider())
 
     assert isinstance(container.get(IntRepo), ConcreteRepo)
+
+
+class _Dep:
+    pass
+
+
+def test_protocol_first_with_parents() -> None:
+    class Proto(Protocol):
+        pass
+
+    class Base:
+        def __init__(self, dep: _Dep) -> None:
+            self.dep = dep
+
+    class Impl(Proto, Base):
+        pass
+
+    provider = Provider(scope=Scope.APP)
+    provider.provide(_Dep)
+    provider.provide(WithParents[Impl])
+
+    container = make_container(provider)
+    result = container.get(Impl)
+    assert isinstance(result, Impl)
+    assert isinstance(result.dep, _Dep)
+    assert container.get(Proto) is result
+    assert container.get(Base) is result
+
+

tests/unit/test_provider.py

@@ -413,6 +413,98 @@ class MyImpl(MyProto):
     assert factory.dependencies == []
 
 
+class _Dep:
+    pass
+
+
+def test_provide_multiple_protocols_before_base():
+    class Proto1(Protocol):
+        pass
+
+    class Proto2(Protocol):
+        pass
+
+    class Base:
+        def __init__(self, dep: _Dep) -> None:
+            self.dep = dep
+
+    class Multi(Proto1, Proto2, Base):
+        pass
+
+    provider = Provider(scope=Scope.APP)
+    provider.provide(_Dep)
+    provider.provide(Multi)
+
+    container = make_container(provider)
+    result = container.get(Multi)
+    assert isinstance(result, Multi)
+    assert isinstance(result.dep, _Dep)
+
+
+def test_provide_own_init_overrides_protocol_stub():
+    class Proto(Protocol):
+        pass
+
+    class Base:
+        def __init__(self, dep: _Dep) -> None:
+            self.dep = dep
+
+    class Impl(Proto, Base):
+        def __init__(self, dep: _Dep) -> None:
+            self.own_dep = dep
+
+    provider = Provider(scope=Scope.APP)
+    provider.provide(_Dep)
+    provider.provide(Impl)
+
+    container = make_container(provider)
+    result = container.get(Impl)
+    assert isinstance(result, Impl)
+    assert isinstance(result.own_dep, _Dep)
+
+
+def test_provide_protocol_with_explicit_init():
+    class ProtoWithInit(Protocol):
+        def __init__(self, dep: _Dep) -> None: ...
+
+    class Impl(ProtoWithInit):
+        def __init__(self, dep: _Dep) -> None:
+            self.dep = dep
+
+    provider = Provider(scope=Scope.APP)
+    provider.provide(_Dep)
+    provider.provide(Impl)
+
+    container = make_container(provider)
+    result = container.get(Impl)
+    assert isinstance(result, Impl)
+    assert isinstance(result.dep, _Dep)
+
+
+def test_provide_deep_hierarchy_with_protocol():
+    class Proto(Protocol):
+        pass
+
+    class GrandBase:
+        def __init__(self, dep: _Dep) -> None:
+            self.dep = dep
+
+    class Base(GrandBase):
+        pass
+
+    class Impl(Proto, Base):
+        pass
+
+    provider = Provider(scope=Scope.APP)
+    provider.provide(_Dep)
+    provider.provide(Impl)
+
+    container = make_container(provider)
+    result = container.get(Impl)
+    assert isinstance(result, Impl)
+    assert isinstance(result.dep, _Dep)
+
+
 class A:
     pass