Run mypy with falcon 4.x (#1199)

requirements/adapter.txt

@@ -8,7 +8,7 @@ chalice>=1.28,<2; python_version>"3.6"
 CherryPy>=18,<19
 Django>=3,<6
 falcon>=2,<4; python_version<"3.11"
-falcon>=3.1.1,<4; python_version>="3.11"
+falcon>=3.1.1,<5; python_version>="3.11"
 fastapi>=0.70.0,<1
 Flask>=1,<4
 Werkzeug>=2,<4

slack_bolt/adapter/falcon/async_resource.py

@@ -1,8 +1,8 @@
 from datetime import datetime
 from http import HTTPStatus
 
-from falcon import version as falcon_version  # type: ignore[import-untyped]
-from falcon.asgi import Request, Response  # type: ignore[import-untyped]
+from falcon import version as falcon_version
+from falcon.asgi import Request, Response
 from slack_bolt import BoltResponse
 from slack_bolt.async_app import AsyncApp
 from slack_bolt.error import BoltError
@@ -41,7 +41,8 @@ async def on_get(self, req: Request, resp: Response):
                 return
 
         resp.status = "404"
-        resp.body = "The page is not found..."
+        # Falcon 4.x w/ mypy fails to correctly infer the str type here
+        resp.body = "The page is not found..."  # type: ignore[assignment]
 
     async def on_post(self, req: Request, resp: Response):
         bolt_req = await self._to_bolt_request(req)

slack_bolt/adapter/falcon/resource.py

@@ -1,7 +1,7 @@
 from datetime import datetime
 from http import HTTPStatus
 
-from falcon import Request, Response, version as falcon_version  # type: ignore[import-untyped]
+from falcon import Request, Response, version as falcon_version
 
 from slack_bolt import BoltResponse
 from slack_bolt.app import App
@@ -35,7 +35,8 @@ def on_get(self, req: Request, resp: Response):
                 return
 
         resp.status = "404"
-        resp.body = "The page is not found..."
+        # Falcon 4.x w/ mypy fails to correctly infer the str type here
+        resp.body = "The page is not found..."  # type: ignore[assignment]
 
     def on_post(self, req: Request, resp: Response):
         bolt_req = self._to_bolt_request(req)
@@ -51,7 +52,8 @@ def _to_bolt_request(self, req: Request) -> BoltRequest:
 
     def _write_response(self, bolt_resp: BoltResponse, resp: Response):
         if falcon_version.__version__.startswith("2."):
-            resp.body = bolt_resp.body
+            # Falcon 4.x w/ mypy fails to correctly infer the str type here
+            resp.body = bolt_resp.body  # type: ignore[assignment]
         else:
             resp.text = bolt_resp.body