Fix #1743: scene handling for channel updates (#1763)

* Fix scene handling for channel updates with missing FSM state (#1743)

* Add changelog entry for scene handling fix

* Refine scene context error handling

tests/test_issues/test_1743_channel_post_with_scenes.py

@@ -0,0 +1,118 @@
+from datetime import datetime
+
+import pytest
+
+from aiogram import Dispatcher, F, Router
+from aiogram.fsm.context import FSMContext
+from aiogram.fsm.scene import Scene, SceneRegistry, on
+from aiogram.fsm.strategy import FSMStrategy
+from aiogram.types import Chat, Message, Update
+from tests.mocked_bot import MockedBot
+
+CHANNEL_ID = -1001234567890
+
+
+class BrowseScene(Scene, state="browse"):
+    pass
+
+
+class ChannelStateScene(Scene, state="channel_state"):
+    @on.channel_post()
+    async def save_message_id(
+        self,
+        message: Message,
+        state: FSMContext,
+    ) -> int:
+        await state.update_data(last_message_id=message.message_id)
+        return message.message_id
+
+
+@pytest.mark.parametrize("update_type", ["channel_post", "edited_channel_post"])
+async def test_channel_events_with_scenes_do_not_require_fsm_state(
+    bot: MockedBot,
+    update_type: str,
+):
+    dispatcher = Dispatcher()
+    channel_router = Router()
+
+    if update_type == "channel_post":
+        channel_router.channel_post.filter(F.chat.id == CHANNEL_ID)
+
+        @channel_router.channel_post()
+        async def on_channel_post(message: Message):
+            return message.message_id
+    else:
+        channel_router.edited_channel_post.filter(F.chat.id == CHANNEL_ID)
+
+        @channel_router.edited_channel_post()
+        async def on_edited_channel_post(message: Message):
+            return message.message_id
+
+    dispatcher.include_router(channel_router)
+    SceneRegistry(dispatcher).add(BrowseScene)
+
+    message = Message(
+        message_id=1,
+        date=datetime.now(),
+        chat=Chat(id=CHANNEL_ID, type="channel"),
+        text="test",
+    )
+
+    kwargs = {"update_id": 1, update_type: message}
+    update = Update(**kwargs)
+
+    result = await dispatcher.feed_update(bot, update)
+    assert result == 1
+
+
+async def test_channel_scene_has_fsm_state_with_chat_strategy(bot: MockedBot):
+    dispatcher = Dispatcher(fsm_strategy=FSMStrategy.CHAT)
+    router = Router()
+
+    @router.channel_post((F.chat.id == CHANNEL_ID) & (F.text == "enter"))
+    async def enter_channel_state(message: Message, state: FSMContext):
+        await state.set_state(ChannelStateScene.__scene_config__.state)
+        return message.message_id
+
+    dispatcher.include_router(router)
+    SceneRegistry(dispatcher).add(ChannelStateScene)
+
+    initial_update = Update(
+        update_id=1,
+        channel_post=Message(
+            message_id=10,
+            date=datetime.now(),
+            chat=Chat(id=CHANNEL_ID, type="channel"),
+            text="enter",
+        ),
+    )
+    await dispatcher.feed_update(bot, initial_update)
+
+    active_state = await dispatcher.fsm.storage.get_state(
+        key=dispatcher.fsm.get_context(
+            bot=bot,
+            chat_id=CHANNEL_ID,
+            user_id=CHANNEL_ID,
+        ).key
+    )
+    assert active_state == ChannelStateScene.__scene_config__.state
+
+    scene_update = Update(
+        update_id=2,
+        channel_post=Message(
+            message_id=11,
+            date=datetime.now(),
+            chat=Chat(id=CHANNEL_ID, type="channel"),
+            text="scene",
+        ),
+    )
+    result = await dispatcher.feed_update(bot, scene_update)
+    assert result == 11
+    state_data = await dispatcher.fsm.storage.get_data(
+        key=dispatcher.fsm.get_context(
+            bot=bot,
+            chat_id=CHANNEL_ID,
+            user_id=CHANNEL_ID,
+        ).key
+    )
+    assert state_data["last_message_id"] == 11