Fix path param warning for request handlers

robyn/router.py

@@ -1,7 +1,7 @@
 import inspect
 import logging
 from abc import ABC, abstractmethod
-from collections.abc import Callable
+from collections.abc import Callable, Mapping
 from functools import wraps
 from types import CoroutineType
 from typing import NamedTuple, is_typeddict
@@ -34,6 +34,9 @@
 # never receive the Response and can't mutate it either.
 _JSON_HEADERS = Headers({"Content-Type": "application/json"})
 _TEXT_HEADERS = Headers({"Content-Type": "text/plain"})
+_REQUEST_PARAM_NAMES = {"r", "req", "request"}
+_PATH_PARAMS_PARAM_NAMES = {"path_params"}
+_PATH_PARAM_ACCESS_TYPES = (Request, PathParams)
 
 
 def lower_http_method(method: HttpMethod):
@@ -72,6 +75,13 @@ def __init__(self) -> None:
         super().__init__()
         self.routes: list[Route] = []
 
+    def _handler_can_access_path_params(self, handler_params: Mapping[str, inspect.Parameter]) -> bool:
+        for param in handler_params.values():
+            if param.annotation in _PATH_PARAM_ACCESS_TYPES:
+                return True
+
+        return bool((_REQUEST_PARAM_NAMES | _PATH_PARAMS_PARAM_NAMES) & set(handler_params))
+
     def _format_tuple_response(self, res: tuple) -> Response:
         if len(res) != 3:
             raise ValueError("Tuple should have 3 elements")
@@ -151,7 +161,7 @@ def add_route(  # type: ignore
         handler_params = inspect.signature(handler).parameters
         handler_param_names = set(handler_params.keys())
 
-        unused_route_params = route_param_names - handler_param_names
+        unused_route_params = set() if self._handler_can_access_path_params(handler_params) else route_param_names - handler_param_names
         if unused_route_params:
             _logger.warning(
                 "Route '%s' declares path params %s but handler '%s' doesn't use them",

unit_tests/test_router_path_param_warnings.py

@@ -0,0 +1,102 @@
+import logging
+
+import pytest
+
+from robyn.robyn import HttpMethod, Request
+from robyn.router import Router
+from robyn.types import PathParams
+
+
+def add_get_route(router, endpoint, handler):
+    router.add_route(
+        route_type=HttpMethod.GET,
+        endpoint=endpoint,
+        handler=handler,
+        is_const=False,
+        auth_required=False,
+        openapi_name="",
+        openapi_tags=[],
+        exception_handler=None,
+        injected_dependencies={"router_dependencies": {}, "global_dependencies": {}},
+    )
+
+
+def path_param_warning_messages(caplog):
+    return [record.getMessage() for record in caplog.records if record.name == "robyn.router" and "declares path params" in record.getMessage()]
+
+
+def handler_with_request_name(request):
+    return request
+
+
+def handler_with_req_name(req):
+    return req
+
+
+def handler_with_r_name(r):
+    return r
+
+
+def handler_with_path_params_name(path_params):
+    return path_params
+
+
+def handler_with_path_param_name(key_id):
+    return key_id
+
+
+def handler_with_typed_request(request_data: Request):
+    return request_data
+
+
+def handler_with_typed_path_params(path_data: PathParams):
+    return path_data
+
+
+def handler_with_typed_request_and_named_param(request_data: Request, user_id):
+    return request_data, user_id
+
+
+@pytest.mark.parametrize(
+    "handler",
+    [
+        handler_with_request_name,
+        handler_with_req_name,
+        handler_with_r_name,
+        handler_with_path_params_name,
+        handler_with_path_param_name,
+        handler_with_typed_request,
+        handler_with_typed_path_params,
+    ],
+)
+def test_path_param_warning_skipped_for_request_or_path_params_access(caplog, handler):
+    caplog.set_level(logging.WARNING, logger="robyn.router")
+
+    add_get_route(Router(), "/v1/keys/:key_id", handler)
+
+    assert path_param_warning_messages(caplog) == []
+
+
+def test_path_param_warning_skipped_when_request_can_access_remaining_params(caplog):
+    caplog.set_level(logging.WARNING, logger="robyn.router")
+
+    add_get_route(Router(), "/users/:user_id/posts/:post_id", handler_with_typed_request_and_named_param)
+
+    assert path_param_warning_messages(caplog) == []
+
+
+def test_path_param_warning_logged_when_param_is_not_accessible(caplog):
+    def handler():
+        return "ok"
+
+    caplog.set_level(logging.WARNING, logger="robyn.router")
+
+    add_get_route(Router(), "/users/:user_id/posts/:post_id", handler)
+
+    warning_messages = path_param_warning_messages(caplog)
+
+    assert len(warning_messages) == 1
+    assert "Route '/users/:user_id/posts/:post_id' declares path params" in warning_messages[0]
+    assert "user_id" in warning_messages[0]
+    assert "post_id" in warning_messages[0]
+    assert "handler 'handler' doesn't use them" in warning_messages[0]