Fix typing of params ids callable form

The previous typing had an object passed to the user, which they can't
do anything with without asserting, which is inconvenient. Change it to
Any instead.

Note that what comes *back* to pytest (the return value) should be an
`object`, because we want to handle arbitrary objects without assuming
anything about them.

Author: bluetech

src/_pytest/fixtures.py

@@ -976,7 +976,7 @@ def __init__(
         ids: Optional[
             Union[
                 Tuple[Union[None, str, float, int, bool], ...],
-                Callable[[object], Optional[object]],
+                Callable[[Any], Optional[object]],
             ]
         ] = None,
     ) -> None:
@@ -1128,13 +1128,13 @@ def _ensure_immutable_ids(
     ids: Optional[
         Union[
             Iterable[Union[None, str, float, int, bool]],
-            Callable[[object], Optional[object]],
+            Callable[[Any], Optional[object]],
         ]
     ],
 ) -> Optional[
     Union[
         Tuple[Union[None, str, float, int, bool], ...],
-        Callable[[object], Optional[object]],
+        Callable[[Any], Optional[object]],
     ]
 ]:
     if ids is None:
@@ -1180,7 +1180,7 @@ class FixtureFunctionMarker:
     ids = attr.ib(
         type=Union[
             Tuple[Union[None, str, float, int, bool], ...],
-            Callable[[object], Optional[object]],
+            Callable[[Any], Optional[object]],
         ],
         default=None,
         converter=_ensure_immutable_ids,
@@ -1223,7 +1223,7 @@ def fixture(
     ids: Optional[
         Union[
             Iterable[Union[None, str, float, int, bool]],
-            Callable[[object], Optional[object]],
+            Callable[[Any], Optional[object]],
         ]
     ] = ...,
     name: Optional[str] = ...
@@ -1241,7 +1241,7 @@ def fixture(  # noqa: F811
     ids: Optional[
         Union[
             Iterable[Union[None, str, float, int, bool]],
-            Callable[[object], Optional[object]],
+            Callable[[Any], Optional[object]],
         ]
     ] = ...,
     name: Optional[str] = None
@@ -1258,7 +1258,7 @@ def fixture(  # noqa: F811
     ids: Optional[
         Union[
             Iterable[Union[None, str, float, int, bool]],
-            Callable[[object], Optional[object]],
+            Callable[[Any], Optional[object]],
         ]
     ] = None,
     name: Optional[str] = None

src/_pytest/mark/structures.py

@@ -433,7 +433,7 @@ def __call__(  # type: ignore[override]
             ids: Optional[
                 Union[
                     Iterable[Union[None, str, float, int, bool]],
-                    Callable[[object], Optional[object]],
+                    Callable[[Any], Optional[object]],
                 ]
             ] = ...,
             scope: Optional[_Scope] = ...

src/_pytest/python.py

@@ -11,6 +11,7 @@
 from collections import defaultdict
 from collections.abc import Sequence
 from functools import partial
+from typing import Any
 from typing import Callable
 from typing import Dict
 from typing import Generator
@@ -920,7 +921,7 @@ def parametrize(
         ids: Optional[
             Union[
                 Iterable[Union[None, str, float, int, bool]],
-                Callable[[object], Optional[object]],
+                Callable[[Any], Optional[object]],
             ]
         ] = None,
         scope: "Optional[_Scope]" = None,
@@ -1040,7 +1041,7 @@ def _resolve_arg_ids(
         ids: Optional[
             Union[
                 Iterable[Union[None, str, float, int, bool]],
-                Callable[[object], Optional[object]],
+                Callable[[Any], Optional[object]],
             ]
         ],
         parameters: typing.Sequence[ParameterSet],
@@ -1226,7 +1227,7 @@ def _idval(
     val: object,
     argname: str,
     idx: int,
-    idfn: Optional[Callable[[object], Optional[object]]],
+    idfn: Optional[Callable[[Any], Optional[object]]],
     nodeid: Optional[str],
     config: Optional[Config],
 ) -> str:
@@ -1266,7 +1267,7 @@ def _idvalset(
     idx: int,
     parameterset: ParameterSet,
     argnames: Iterable[str],
-    idfn: Optional[Callable[[object], Optional[object]]],
+    idfn: Optional[Callable[[Any], Optional[object]]],
     ids: Optional[List[Union[None, str]]],
     nodeid: Optional[str],
     config: Optional[Config],
@@ -1287,7 +1288,7 @@ def _idvalset(
 def idmaker(
     argnames: Iterable[str],
     parametersets: Iterable[ParameterSet],
-    idfn: Optional[Callable[[object], Optional[object]]] = None,
+    idfn: Optional[Callable[[Any], Optional[object]]] = None,
     ids: Optional[List[Union[None, str]]] = None,
     config: Optional[Config] = None,
     nodeid: Optional[str] = None,

testing/typing_checks.py

@@ -10,3 +10,15 @@
 @pytest.mark.xfail(raises=RuntimeError)
 def check_mark_xfail_raises() -> None:
     pass
+
+
+# Issue #7494.
+@pytest.fixture(params=[(0, 0), (1, 1)], ids=lambda x: str(x[0]))
+def check_fixture_ids_callable() -> None:
+    pass
+
+
+# Issue #7494.
+@pytest.mark.parametrize("func", [str, int], ids=lambda x: str(x.__name__))
+def check_parametrize_ids_callable(func) -> None:
+    pass