fix: raise a clear RuntimeError when inject runs without setup_di

README.md

@@ -74,7 +74,7 @@ Pass `auto_inject=True` to `setup_di` to wrap every handler already registered o
 |---|---|
 | `setup_di(dispatcher, container, *, auto_inject=False)` | Stores the container on the dispatcher, registers the update/event providers, wires `dispatcher.startup`/`dispatcher.shutdown` to open/close it, and installs the per-update middleware. With `auto_inject=True`, also wraps every handler already registered at startup |
 | `FromDI(dependency)` | Inert marker (used with `@inject`) that resolves a provider or type from the per-update child container |
-| `inject(handler)` | Decorator for an aiogram handler; resolves its `FromDI`-annotated parameters. Not needed when `setup_di(..., auto_inject=True)` is used |
+| `inject(handler)` | Decorator for an aiogram handler; resolves its `FromDI`-annotated parameters. Not needed when `setup_di(..., auto_inject=True)` is used. Raises `RuntimeError` naming `setup_di` when an update reaches it without the middleware installed |
 | `fetch_di_container(dispatcher)` | Returns the root `Container` stored on the dispatcher |
 | `aiogram_update_provider` | `ContextProvider` for the current `aiogram.types.Update` (`REQUEST` scope) |
 | `aiogram_event_provider` | `ContextProvider` for the current `aiogram.types.TelegramObject` (`REQUEST` scope) — the concrete event unwrapped from the `Update` |

modern_di_aiogram/dialog.py

@@ -13,7 +13,7 @@
 
 from modern_di import Container, integrations
 
-from modern_di_aiogram.main import _CHILD_CONTAINER_KEY, FromDI
+from modern_di_aiogram.main import FromDI, _fetch_child_container
 
 
 __all__ = [
@@ -27,10 +27,10 @@
 def _container_from_call(args: tuple[typing.Any, ...], kwargs: dict[str, typing.Any]) -> Container:
     if not args:
         # getter: aiogram-dialog calls it as getter(**manager.middleware_data)
-        return typing.cast(Container, kwargs[_CHILD_CONTAINER_KEY])
+        return _fetch_child_container(kwargs)
     # callbacks carry a DialogManager positionally: (data, manager) or (event, widget, manager[, item])
     manager = args[-1] if len(args) == _ON_DIALOG_EVENT_ARGS else args[2]
-    return typing.cast(Container, manager.middleware_data[_CHILD_CONTAINER_KEY])
+    return _fetch_child_container(manager.middleware_data)
 
 
 def inject(

modern_di_aiogram/main.py

@@ -20,6 +20,18 @@
 _CHILD_CONTAINER_KEY = "modern_di_container"
 
 
+def _fetch_child_container(data: typing.Mapping[str, typing.Any]) -> Container:
+    try:
+        return typing.cast(Container, data[_CHILD_CONTAINER_KEY])
+    except KeyError:
+        msg = (
+            "No modern-di container found for this update. "
+            "Call setup_di(dispatcher, container) so updates pass through the modern-di middleware "
+            "before using @inject."
+        )
+        raise RuntimeError(msg) from None
+
+
 class _DiMiddleware(BaseMiddleware):
     def __init__(self, container: Container) -> None:
         self.container = container
@@ -74,9 +86,9 @@ def inject(func: typing.Callable[..., typing.Awaitable[T]]) -> typing.Callable[.
         )
 
     async def wrapper(*args: typing.Any, **kwargs: typing.Any) -> T:  # noqa: ANN401
-        container: Container = (
-            kwargs.pop(_CHILD_CONTAINER_KEY) if container_param_injected else kwargs[_CHILD_CONTAINER_KEY]
-        )
+        container = _fetch_child_container(kwargs)
+        if container_param_injected:
+            del kwargs[_CHILD_CONTAINER_KEY]
         resolved = integrations.resolve_markers(container, di_params)
         return await func(*args, **kwargs, **resolved)
 

tests/test_dialog.py

@@ -178,3 +178,23 @@ async def _start(_message: Message, dialog_manager: DialogManager) -> None:
     await client.dp.emit_shutdown()
 
     assert teardowns == ["closed"]
+
+
+def _dialog_without_setup_di(dialog: Dialog) -> BotClient:
+    dispatcher = Dispatcher()
+    dispatcher.message.register(_start_command, CommandStart())
+    dispatcher.include_router(dialog)
+    setup_dialogs(dispatcher, message_manager=MockMessageManager())
+    return BotClient(dispatcher)
+
+
+async def test_getter_without_setup_di_names_the_fix() -> None:
+    client = _dialog_without_setup_di(Dialog(Window(Format("{name}"), state=MainSG.window, getter=main_getter)))
+    with pytest.raises(RuntimeError, match=r"setup_di\(dispatcher, container\)"):
+        await client.send("/start")
+
+
+async def test_callback_without_setup_di_names_the_fix() -> None:
+    client = _dialog_without_setup_di(Dialog(Window(Const("x"), state=MainSG.window), on_start=on_start))
+    with pytest.raises(RuntimeError, match=r"setup_di\(dispatcher, container\)"):
+        await client.send("/start")

tests/test_inject.py

@@ -1,6 +1,7 @@
 import contextlib
 import typing
 
+import pytest
 from aiogram import Bot, Dispatcher
 from aiogram.types import Message
 from modern_di import Container, Group, Scope, providers
@@ -98,3 +99,17 @@ async def handler(
     await dispatcher.emit_shutdown()
 
     assert teardowns == ["closed"]  # per-update child closed (finalizer ran) on the error path
+
+
+async def test_inject_without_setup_di_names_the_fix(bot: Bot) -> None:
+    dispatcher = Dispatcher()
+
+    @dispatcher.message()
+    @inject
+    async def handler(
+        message: Message,
+        _app: typing.Annotated[SimpleCreator, FromDI(SimpleCreator)],
+    ) -> None: ...
+
+    with pytest.raises(RuntimeError, match=r"setup_di\(dispatcher, container\)"):
+        await dispatcher.feed_update(bot, make_message_update())