Increase stacklevel for UserWarning about AppKey usage (#7484)

Author: cdce8p

CONTRIBUTORS.txt

@@ -215,6 +215,7 @@ Lukasz Marcin Dobrzanski
 Makc Belousow
 Manuel Miranda
 Marat Sharafutdinov
+Marc Mueller
 Marco Paolini
 Mariano Anaya
 Mariusz Masztalerczuk

aiohttp/web_app.py

@@ -173,7 +173,8 @@ def __setitem__(self, key: Union[str, AppKey[_T]], value: Any) -> None:
             warnings.warn(
                 "It is recommended to use web.AppKey instances for keys.\n"
                 + "https://docs.aiohttp.org/en/stable/web_advanced.html"
-                + "#application-s-config"
+                + "#application-s-config",
+                stacklevel=2,
             )
         self._state[key] = value
 

tests/test_web_app.py

@@ -144,8 +144,12 @@ def test_appkey_repr_annotated() -> None:
 
 def test_app_str_keys() -> None:
     app = web.Application()
-    with pytest.warns(UserWarning, match=r"web_advanced\.html#application-s-config"):
+    with pytest.warns(
+        UserWarning, match=r"web_advanced\.html#application-s-config"
+    ) as checker:
         app["key"] = "value"
+        # Check that the error is emitted at the call site (stacklevel=2)
+        assert checker[0].filename == __file__
     assert app["key"] == "value"