Fix bug in route name validation (#5051)

* Fix bug in route name validation

* Add changelog

* Fix test end error msg

* Add test

CHANGES/4691.bugfix

@@ -0,0 +1 @@
+Fix the register_resource function to validate route name before splitting it so that route name can include python keywords.

CONTRIBUTORS.txt

@@ -262,6 +262,7 @@ Thomas Forbes
 Thomas Grainger
 Tolga Tezel
 Tomasz Trebski
+Toshiaki Tanaka
 Trinh Hoang Nhu
 Vadim Suharnikov
 Vaibhav Sagar

aiohttp/web_urldispatcher.py

@@ -981,7 +981,11 @@ def register_resource(self, resource: AbstractResource) -> None:
         if name is not None:
             parts = self.NAME_SPLIT_RE.split(name)
             for part in parts:
-                if not part.isidentifier() or keyword.iskeyword(part):
+                if keyword.iskeyword(part):
+                    raise ValueError(f'Incorrect route name {name!r}, '
+                                     'python keywords cannot be used '
+                                     'for route name')
+                if not part.isidentifier():
                     raise ValueError('Incorrect route name {!r}, '
                                      'the name should be a sequence of '
                                      'python identifiers separated '

tests/test_urldispatch.py

@@ -1150,6 +1150,11 @@ def test_invalid_route_name(router) -> None:
         router.add_get('/', make_handler(), name='invalid name')
 
 
+def test_invalid_route_name(router) -> None:
+    with pytest.raises(ValueError):
+        router.add_get('/', make_handler(), name='class')  # identifier
+
+
 def test_frozen_router(router) -> None:
     router.freeze()
     with pytest.raises(RuntimeError):