Fix #370 by adding an alias of next arg (next_) in middleware arguments

slack_bolt/kwargs_injection/args.py

@@ -72,6 +72,8 @@ def handle_buttons(ack, respond, logger, context, body, client):
     # middleware
     next: Callable[[], None]
     """`next()` utility function, which tells the middleware chain that it can continue with the next one"""
+    next_: Callable[[], None]
+    """An alias of `next()` for avoiding the Python built-in method overrides in middleware functions"""
 
     def __init__(
         self,
@@ -93,6 +95,9 @@ def __init__(
         ack: Ack,
         say: Say,
         respond: Respond,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], None],
         **kwargs  # noqa
     ):
@@ -116,3 +121,4 @@ def __init__(
         self.say: Say = say
         self.respond: Respond = respond
         self.next: Callable[[], None] = next
+        self.next_: Callable[[], None] = next

slack_bolt/kwargs_injection/async_args.py

@@ -71,6 +71,8 @@ async def handle_buttons(ack, respond, logger, context, body, client):
     # middleware
     next: Callable[[], Awaitable[None]]
     """`next()` utility function, which tells the middleware chain that it can continue with the next one"""
+    next_: Callable[[], Awaitable[None]]
+    """An alias of `next()` for avoiding the Python built-in method overrides in middleware functions"""
 
     def __init__(
         self,
@@ -115,3 +117,4 @@ def __init__(
         self.say: AsyncSay = say
         self.respond: AsyncRespond = respond
         self.next: Callable[[], Awaitable[None]] = next
+        self.next_: Callable[[], Awaitable[None]] = next

slack_bolt/kwargs_injection/async_utils.py

@@ -52,6 +52,7 @@ def build_async_required_kwargs(
         "respond": request.context.respond,
         # middleware
         "next": next_func,
+        "next_": next_func,  # for the middleware using Python's built-in `next()` function
     }
     all_available_args["payload"] = (
         all_available_args["options"]

slack_bolt/kwargs_injection/utils.py

@@ -52,6 +52,7 @@ def build_required_kwargs(
         "respond": request.context.respond,
         # middleware
         "next": next_func,
+        "next_": next_func,  # for the middleware using Python's built-in `next()` function
     }
     all_available_args["payload"] = (
         all_available_args["options"]

slack_bolt/listener/listener.py

@@ -45,10 +45,10 @@ def run_middleware(
         for m in self.middleware:
             middleware_state = {"next_called": False}
 
-            def next():
+            def next_():
                 middleware_state["next_called"] = True
 
-            resp = m.process(req=req, resp=resp, next=next)
+            resp = m.process(req=req, resp=resp, next=next_)
             if not middleware_state["next_called"]:
                 # next() was not called in this middleware
                 return (resp, True)

slack_bolt/logger/messages.py

@@ -99,7 +99,7 @@ def warning_unhandled_by_global_middleware(  # type: ignore
     name: str, req: Union[BoltRequest, "AsyncBoltRequest"]  # type: ignore
 ) -> str:  # type: ignore
     return (
-        f"A global middleware ({name}) skipped calling `next()` "
+        f"A global middleware ({name}) skipped calling either `next()` or `next_()` "
         f"without providing a response for the request ({req.body})"
     )
 

slack_bolt/middleware/async_custom_middleware.py

@@ -31,6 +31,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> BoltResponse:
         return await self.func(

slack_bolt/middleware/async_middleware.py

@@ -14,6 +14,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> Optional[BoltResponse]:
         """Processes a request data before other middleware and listeners.
@@ -24,6 +27,14 @@ async def simple_middleware(req, resp, next):
                 # do something here
                 await next()
 
+        This `async_process(req, resp, next)` method is supposed to be invoked only inside bolt-python.
+        If you want to avoid the name `next()` in your middleware functions, you can use `next_()` method instead.
+
+            @app.middleware
+            async def simple_middleware(req, resp, next_):
+                # do something here
+                await next_()
+
         Args:
             req: The incoming request
             resp: The response

slack_bolt/middleware/authorization/async_multi_teams_authorization.py

@@ -28,6 +28,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> BoltResponse:
         if _is_no_auth_required(req):

slack_bolt/middleware/authorization/async_single_team_authorization.py

@@ -22,6 +22,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> BoltResponse:
         if _is_no_auth_required(req):

slack_bolt/middleware/authorization/single_team_authorization.py

@@ -30,6 +30,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> BoltResponse:
         if _is_no_auth_required(req):

slack_bolt/middleware/custom_middleware.py

@@ -27,6 +27,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> BoltResponse:
         return self.func(

slack_bolt/middleware/message_listener_matches/async_message_listener_matches.py

@@ -16,6 +16,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> BoltResponse:
         text = req.body.get("event", {}).get("text", "")

slack_bolt/middleware/message_listener_matches/message_listener_matches.py

@@ -16,6 +16,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> BoltResponse:
         text = req.body.get("event", {}).get("text", "")

slack_bolt/middleware/middleware.py

@@ -14,6 +14,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> Optional[BoltResponse]:
         """Processes a request data before other middleware and listeners.
@@ -24,6 +27,14 @@ def simple_middleware(req, resp, next):
                 # do something here
                 next()
 
+        This `process(req, resp, next)` method is supposed to be invoked only inside bolt-python.
+        If you want to avoid the name `next()` in your middleware functions, you can use `next_()` method instead.
+
+            @app.middleware
+            def simple_middleware(req, resp, next_):
+                # do something here
+                next_()
+
         Args:
             req: The incoming request
             resp: The response

slack_bolt/middleware/request_verification/async_request_verification.py

@@ -18,6 +18,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> BoltResponse:
         if self._can_skip(req.mode, req.body):

slack_bolt/middleware/request_verification/request_verification.py

@@ -26,6 +26,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> BoltResponse:
         if self._can_skip(req.mode, req.body):

slack_bolt/middleware/ssl_check/async_ssl_check.py

@@ -12,6 +12,9 @@ async def async_process(
         *,
         req: AsyncBoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], Awaitable[BoltResponse]],
     ) -> BoltResponse:
         if self._is_ssl_check_request(req.body):

slack_bolt/middleware/ssl_check/ssl_check.py

@@ -23,6 +23,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> BoltResponse:
         if self._is_ssl_check_request(req.body):

slack_bolt/middleware/url_verification/url_verification.py

@@ -19,6 +19,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> BoltResponse:
         if self._is_url_verification_request(req.body):

slack_bolt/workflows/step/step_middleware.py

@@ -21,6 +21,9 @@ def process(
         *,
         req: BoltRequest,
         resp: BoltResponse,
+        # As this method is not supposed to be invoked by bolt-python users,
+        # the naming conflict with the built-in one affects
+        # only the internals of this method
         next: Callable[[], BoltResponse],
     ) -> Optional[BoltResponse]:
 

tests/scenario_tests/test_middleware.py

@@ -87,6 +87,53 @@ def test_next_call(self):
         assert response.body == "acknowledged!"
         assert_auth_test_count(self, 1)
 
+    def test_decorator_next_call(self):
+        app = App(
+            client=self.web_client,
+            signing_secret=self.signing_secret,
+        )
+
+        @app.middleware
+        def just_next(next):
+            next()
+
+        app.shortcut("test-shortcut")(just_ack)
+
+        response = app.dispatch(self.build_request())
+        assert response.status == 200
+        assert response.body == "acknowledged!"
+        assert_auth_test_count(self, 1)
+
+    def test_next_call_(self):
+        app = App(
+            client=self.web_client,
+            signing_secret=self.signing_secret,
+        )
+        app.use(just_next_)
+        app.shortcut("test-shortcut")(just_ack)
+
+        response = app.dispatch(self.build_request())
+        assert response.status == 200
+        assert response.body == "acknowledged!"
+        assert_auth_test_count(self, 1)
+
+    def test_decorator_next_call_(self):
+        app = App(
+            client=self.web_client,
+            signing_secret=self.signing_secret,
+        )
+
+        @app.middleware
+        def just_next_(next_):
+            next_()
+
+        app.shortcut("test-shortcut")(just_ack)
+
+        response = app.dispatch(self.build_request())
+        assert response.status == 200
+        assert response.body == "acknowledged!"
+        assert_auth_test_count(self, 1)
+
     def test_class_call(self):
         class NextClass:
             def __call__(self, next):
@@ -104,6 +151,23 @@ def __call__(self, next):
         assert response.body == "acknowledged!"
         assert_auth_test_count(self, 1)
 
+    def test_class_call_(self):
+        class NextUnderscoreClass:
+            def __call__(self, next_):
+                next_()
+
+        app = App(
+            client=self.web_client,
+            signing_secret=self.signing_secret,
+        )
+        app.use(NextUnderscoreClass())
+        app.shortcut("test-shortcut")(just_ack)
+
+        response = app.dispatch(self.build_request())
+        assert response.status == 200
+        assert response.body == "acknowledged!"
+        assert_auth_test_count(self, 1)
+
 
 def just_ack(ack):
     ack("acknowledged!")
@@ -115,3 +179,7 @@ def no_next():
 
 def just_next(next):
     next()
+
+
+def just_next_(next_):
+    next_()