From 0303285d7c554435a701d056fb907092f50371c5 Mon Sep 17 00:00:00 2001
From: Bruno Oliveira <bruno@pytest.org>
Date: Tue, 26 Nov 2024 11:02:41 -0300
Subject: [PATCH 1/4] typing: Improve FixtureDefinition and FixtureDef

* Carry around parameters and return value in `FixtureFunctionDefinition`.
* Add `FixtureParams` to `FixtureDef`.

Follow up to #12473.
---
 pyproject.toml             |   1 +
 src/_pytest/fixtures.py    | 108 +++++++++++++++++++++----------------
 src/_pytest/hookspec.py    |   4 +-
 src/_pytest/python.py      |   6 +--
 src/_pytest/setuponly.py   |   7 +--
 src/_pytest/setupplan.py   |   4 +-
 testing/python/metafunc.py |   4 +-
 7 files changed, 78 insertions(+), 56 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index dce6a0870e1..0b0164862a9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -52,6 +52,7 @@ dependencies = [
     "packaging",
     "pluggy>=1.5,<2",
     "tomli>=1; python_version<'3.11'",
+    "typing-extensions; python_version<'3.10'",
 ]
 optional-dependencies.dev = [
     "argcomplete",
diff --git a/src/_pytest/fixtures.py b/src/_pytest/fixtures.py
index 8b79dbcb932..3a4b6fe5e62 100644
--- a/src/_pytest/fixtures.py
+++ b/src/_pytest/fixtures.py
@@ -75,6 +75,13 @@
 if sys.version_info < (3, 11):
     from exceptiongroup import BaseExceptionGroup
 
+if sys.version_info < (3, 10):
+    from typing_extensions import ParamSpec
+    from typing_extensions import TypeAlias
+else:
+    from typing import ParamSpec
+    from typing import TypeAlias
+
 
 if TYPE_CHECKING:
     from _pytest.python import CallSpec2
@@ -84,14 +91,17 @@
 
 # The value of the fixture -- return/yield of the fixture function (type variable).
 FixtureValue = TypeVar("FixtureValue")
-# The type of the fixture function (type variable).
-FixtureFunction = TypeVar("FixtureFunction", bound=Callable[..., object])
-# The type of a fixture function (type alias generic in fixture value).
-_FixtureFunc = Union[
-    Callable[..., FixtureValue], Callable[..., Generator[FixtureValue]]
+
+# The parameters that a fixture function receives.
+FixtureParams = ParamSpec("FixtureParams")
+
+# The type of fixture function (type alias generic in fixture params and value).
+_FixtureFunc: TypeAlias = Union[
+    Callable[FixtureParams, FixtureValue],
+    Callable[FixtureParams, Generator[FixtureValue, None, None]],
 ]
 # The type of FixtureDef.cached_result (type alias generic in fixture value).
-_FixtureCachedResult = Union[
+_FixtureCachedResult: TypeAlias = Union[
     tuple[
         # The result.
         FixtureValue,
@@ -121,7 +131,7 @@ def pytest_sessionstart(session: Session) -> None:
 
 def get_scope_package(
     node: nodes.Item,
-    fixturedef: FixtureDef[object],
+    fixturedef: FixtureDef[Any, object],
 ) -> nodes.Node | None:
     from _pytest.python import Package
 
@@ -318,7 +328,7 @@ class FuncFixtureInfo:
     # matching the name which are applicable to this function.
     # There may be multiple overriding fixtures with the same name. The
     # sequence is ordered from furthest to closes to the function.
-    name2fixturedefs: dict[str, Sequence[FixtureDef[Any]]]
+    name2fixturedefs: dict[str, Sequence[FixtureDef[Any, Any]]]
 
     def prune_dependency_tree(self) -> None:
         """Recompute names_closure from initialnames and name2fixturedefs.
@@ -359,8 +369,8 @@ def __init__(
         self,
         pyfuncitem: Function,
         fixturename: str | None,
-        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]],
-        fixture_defs: dict[str, FixtureDef[Any]],
+        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any, Any]]],
+        fixture_defs: dict[str, FixtureDef[Any, Any]],
         *,
         _ispytest: bool = False,
     ) -> None:
@@ -403,7 +413,7 @@ def scope(self) -> _ScopeName:
     @abc.abstractmethod
     def _check_scope(
         self,
-        requested_fixturedef: FixtureDef[object] | PseudoFixtureDef[object],
+        requested_fixturedef: FixtureDef[Any, object] | PseudoFixtureDef[object],
         requested_scope: Scope,
     ) -> None:
         raise NotImplementedError()
@@ -544,7 +554,7 @@ def _iter_chain(self) -> Iterator[SubRequest]:
 
     def _get_active_fixturedef(
         self, argname: str
-    ) -> FixtureDef[object] | PseudoFixtureDef[object]:
+    ) -> FixtureDef[Any, object] | PseudoFixtureDef[object]:
         if argname == "request":
             cached_result = (self, [0], None)
             return PseudoFixtureDef(cached_result, Scope.Function)
@@ -616,7 +626,9 @@ def _get_active_fixturedef(
         self._fixture_defs[argname] = fixturedef
         return fixturedef
 
-    def _check_fixturedef_without_param(self, fixturedef: FixtureDef[object]) -> None:
+    def _check_fixturedef_without_param(
+        self, fixturedef: FixtureDef[Any, object]
+    ) -> None:
         """Check that this request is allowed to execute this fixturedef without
         a param."""
         funcitem = self._pyfuncitem
@@ -649,7 +661,7 @@ def _check_fixturedef_without_param(self, fixturedef: FixtureDef[object]) -> Non
             )
             fail(msg, pytrace=False)
 
-    def _get_fixturestack(self) -> list[FixtureDef[Any]]:
+    def _get_fixturestack(self) -> list[FixtureDef[Any, Any]]:
         values = [request._fixturedef for request in self._iter_chain()]
         values.reverse()
         return values
@@ -674,7 +686,7 @@ def _scope(self) -> Scope:
 
     def _check_scope(
         self,
-        requested_fixturedef: FixtureDef[object] | PseudoFixtureDef[object],
+        requested_fixturedef: FixtureDef[Any, object] | PseudoFixtureDef[object],
         requested_scope: Scope,
     ) -> None:
         # TopRequest always has function scope so always valid.
@@ -708,7 +720,7 @@ def __init__(
         scope: Scope,
         param: Any,
         param_index: int,
-        fixturedef: FixtureDef[object],
+        fixturedef: FixtureDef[Any, object],
         *,
         _ispytest: bool = False,
     ) -> None:
@@ -721,7 +733,7 @@ def __init__(
         )
         self._parent_request: Final[FixtureRequest] = request
         self._scope_field: Final = scope
-        self._fixturedef: Final[FixtureDef[object]] = fixturedef
+        self._fixturedef: Final[FixtureDef[Any, object]] = fixturedef
         if param is not NOTSET:
             self.param = param
         self.param_index: Final = param_index
@@ -751,7 +763,7 @@ def node(self):
 
     def _check_scope(
         self,
-        requested_fixturedef: FixtureDef[object] | PseudoFixtureDef[object],
+        requested_fixturedef: FixtureDef[Any, object] | PseudoFixtureDef[object],
         requested_scope: Scope,
     ) -> None:
         if isinstance(requested_fixturedef, PseudoFixtureDef):
@@ -772,7 +784,7 @@ def _check_scope(
                 pytrace=False,
             )
 
-    def _format_fixturedef_line(self, fixturedef: FixtureDef[object]) -> str:
+    def _format_fixturedef_line(self, fixturedef: FixtureDef[Any, object]) -> str:
         factory = fixturedef.func
         path, lineno = getfslineno(factory)
         if isinstance(path, Path):
@@ -886,7 +898,9 @@ def toterminal(self, tw: TerminalWriter) -> None:
 
 
 def call_fixture_func(
-    fixturefunc: _FixtureFunc[FixtureValue], request: FixtureRequest, kwargs
+    fixturefunc: _FixtureFunc[FixtureParams, FixtureValue],
+    request: FixtureRequest,
+    kwargs: FixtureParams.kwargs,
 ) -> FixtureValue:
     if inspect.isgeneratorfunction(fixturefunc):
         fixturefunc = cast(Callable[..., Generator[FixtureValue]], fixturefunc)
@@ -945,9 +959,11 @@ def _eval_scope_callable(
 
 
 @final
-class FixtureDef(Generic[FixtureValue]):
+class FixtureDef(Generic[FixtureParams, FixtureValue]):
     """A container for a fixture definition.
 
+    This is a generic class parametrized on the parameters that a fixture function receives and its return value.
+
     Note: At this time, only explicitly documented fields and methods are
     considered public stable API.
     """
@@ -957,7 +973,7 @@ def __init__(
         config: Config,
         baseid: str | None,
         argname: str,
-        func: _FixtureFunc[FixtureValue],
+        func: _FixtureFunc[FixtureParams, FixtureValue],
         scope: Scope | _ScopeName | Callable[[str, Config], _ScopeName] | None,
         params: Sequence[object] | None,
         ids: tuple[object | None, ...] | Callable[[Any], object | None] | None = None,
@@ -1112,8 +1128,8 @@ def __repr__(self) -> str:
 
 
 def resolve_fixture_function(
-    fixturedef: FixtureDef[FixtureValue], request: FixtureRequest
-) -> _FixtureFunc[FixtureValue]:
+    fixturedef: FixtureDef[FixtureParams, FixtureValue], request: FixtureRequest
+) -> _FixtureFunc[FixtureParams, FixtureValue]:
     """Get the actual callable that can be called to obtain the fixture
     value."""
     fixturefunc = fixturedef.func
@@ -1136,7 +1152,7 @@ def resolve_fixture_function(
 
 
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[FixtureValue], request: SubRequest
+    fixturedef: FixtureDef[FixtureParams, FixtureValue], request: SubRequest
 ) -> FixtureValue:
     """Execution of fixture setup."""
     kwargs = {}
@@ -1192,7 +1208,9 @@ class FixtureFunctionMarker:
     def __post_init__(self, _ispytest: bool) -> None:
         check_ispytest(_ispytest)
 
-    def __call__(self, function: FixtureFunction) -> FixtureFunctionDefinition:
+    def __call__(
+        self, function: Callable[FixtureParams, FixtureValue]
+    ) -> FixtureFunctionDefinition[FixtureParams, FixtureValue]:
         if inspect.isclass(function):
             raise ValueError("class fixtures not supported (maybe in the future)")
 
@@ -1219,12 +1237,10 @@ def __call__(self, function: FixtureFunction) -> FixtureFunctionDefinition:
         return fixture_definition
 
 
-# TODO: paramspec/return type annotation tracking and storing
-class FixtureFunctionDefinition:
+class FixtureFunctionDefinition(Generic[FixtureParams, FixtureValue]):
     def __init__(
         self,
-        *,
-        function: Callable[..., Any],
+        function: Callable[FixtureParams, FixtureValue],
         fixture_function_marker: FixtureFunctionMarker,
         instance: object | None = None,
         _ispytest: bool = False,
@@ -1237,7 +1253,7 @@ def __init__(
         self._fixture_function_marker = fixture_function_marker
         if instance is not None:
             self._fixture_function = cast(
-                Callable[..., Any], function.__get__(instance)
+                Callable[FixtureParams, FixtureValue], function.__get__(instance)
             )
         else:
             self._fixture_function = function
@@ -1246,12 +1262,14 @@ def __init__(
     def __repr__(self) -> str:
         return f"<pytest_fixture({self._fixture_function})>"
 
-    def __get__(self, instance, owner=None):
+    def __get__(
+        self, obj: object, objtype: type | None = None
+    ) -> FixtureFunctionDefinition[FixtureParams, FixtureValue]:
         """Behave like a method if the function it was applied to was a method."""
         return FixtureFunctionDefinition(
             function=self._fixture_function,
             fixture_function_marker=self._fixture_function_marker,
-            instance=instance,
+            instance=obj,
             _ispytest=True,
         )
 
@@ -1270,14 +1288,14 @@ def _get_wrapped_function(self) -> Callable[..., Any]:
 
 @overload
 def fixture(
-    fixture_function: Callable[..., object],
+    fixture_function: Callable[FixtureParams, FixtureValue],
     *,
     scope: _ScopeName | Callable[[str, Config], _ScopeName] = ...,
     params: Iterable[object] | None = ...,
     autouse: bool = ...,
     ids: Sequence[object | None] | Callable[[Any], object | None] | None = ...,
     name: str | None = ...,
-) -> FixtureFunctionDefinition: ...
+) -> FixtureFunctionDefinition[FixtureParams, FixtureValue]: ...
 
 
 @overload
@@ -1293,14 +1311,14 @@ def fixture(
 
 
 def fixture(
-    fixture_function: FixtureFunction | None = None,
+    fixture_function: Callable[FixtureParams, FixtureValue] | None = None,
     *,
     scope: _ScopeName | Callable[[str, Config], _ScopeName] = "function",
     params: Iterable[object] | None = None,
     autouse: bool = False,
     ids: Sequence[object | None] | Callable[[Any], object | None] | None = None,
     name: str | None = None,
-) -> FixtureFunctionMarker | FixtureFunctionDefinition:
+) -> FixtureFunctionMarker | FixtureFunctionDefinition[FixtureParams, FixtureValue]:
     """Decorator to mark a fixture factory function.
 
     This decorator can be used, with or without parameters, to define a
@@ -1507,7 +1525,7 @@ def __init__(self, session: Session) -> None:
         # suite/plugins defined with this name. Populated by parsefactories().
         # TODO: The order of the FixtureDefs list of each arg is significant,
         #       explain.
-        self._arg2fixturedefs: Final[dict[str, list[FixtureDef[Any]]]] = {}
+        self._arg2fixturedefs: Final[dict[str, list[FixtureDef[Any, Any]]]] = {}
         self._holderobjseen: Final[set[object]] = set()
         # A mapping from a nodeid to a list of autouse fixtures it defines.
         self._nodeid_autousenames: Final[dict[str, list[str]]] = {
@@ -1598,7 +1616,7 @@ def getfixtureclosure(
         parentnode: nodes.Node,
         initialnames: tuple[str, ...],
         ignore_args: AbstractSet[str],
-    ) -> tuple[list[str], dict[str, Sequence[FixtureDef[Any]]]]:
+    ) -> tuple[list[str], dict[str, Sequence[FixtureDef[Any, Any]]]]:
         # Collect the closure of all fixtures, starting with the given
         # fixturenames as the initial set.  As we have to visit all
         # factory definitions anyway, we also return an arg2fixturedefs
@@ -1608,7 +1626,7 @@ def getfixtureclosure(
 
         fixturenames_closure = list(initialnames)
 
-        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]] = {}
+        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any, Any]]] = {}
         lastlen = -1
         while lastlen != len(fixturenames_closure):
             lastlen = len(fixturenames_closure)
@@ -1688,7 +1706,7 @@ def _register_fixture(
         self,
         *,
         name: str,
-        func: _FixtureFunc[object],
+        func: _FixtureFunc[Any, object],
         nodeid: str | None,
         scope: Scope | _ScopeName | Callable[[str, Config], _ScopeName] = "function",
         params: Sequence[object] | None = None,
@@ -1823,7 +1841,7 @@ def parsefactories(
 
     def getfixturedefs(
         self, argname: str, node: nodes.Node
-    ) -> Sequence[FixtureDef[Any]] | None:
+    ) -> Sequence[FixtureDef[Any, Any]] | None:
         """Get FixtureDefs for a fixture name which are applicable
         to a given node.
 
@@ -1842,8 +1860,8 @@ def getfixturedefs(
         return tuple(self._matchfactories(fixturedefs, node))
 
     def _matchfactories(
-        self, fixturedefs: Iterable[FixtureDef[Any]], node: nodes.Node
-    ) -> Iterator[FixtureDef[Any]]:
+        self, fixturedefs: Iterable[FixtureDef[Any, Any]], node: nodes.Node
+    ) -> Iterator[FixtureDef[Any, Any]]:
         parentnodeids = {n.nodeid for n in node.iter_parents()}
         for fixturedef in fixturedefs:
             if fixturedef.baseid in parentnodeids:
@@ -1880,7 +1898,7 @@ def get_best_relpath(func) -> str:
         loc = getlocation(func, invocation_dir)
         return bestrelpath(invocation_dir, Path(loc))
 
-    def write_fixture(fixture_def: FixtureDef[object]) -> None:
+    def write_fixture(fixture_def: FixtureDef[Any, object]) -> None:
         argname = fixture_def.argname
         if verbose <= 0 and argname.startswith("_"):
             return
diff --git a/src/_pytest/hookspec.py b/src/_pytest/hookspec.py
index 8b20061d6f0..66700a3938b 100644
--- a/src/_pytest/hookspec.py
+++ b/src/_pytest/hookspec.py
@@ -866,7 +866,7 @@ def pytest_report_from_serializable(
 
 @hookspec(firstresult=True)
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[Any], request: SubRequest
+    fixturedef: FixtureDef[Any, Any], request: SubRequest
 ) -> object | None:
     """Perform fixture setup execution.
 
@@ -894,7 +894,7 @@ def pytest_fixture_setup(
 
 
 def pytest_fixture_post_finalizer(
-    fixturedef: FixtureDef[Any], request: SubRequest
+    fixturedef: FixtureDef[Any, Any], request: SubRequest
 ) -> None:
     """Called after fixture teardown, but before the cache is cleared, so
     the fixture result ``fixturedef.cached_result`` is still available (not
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index 85e3cb0ae71..c8db81e73c9 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -1085,7 +1085,7 @@ def get_direct_param_fixture_func(request: FixtureRequest) -> Any:
 
 
 # Used for storing pseudo fixturedefs for direct parametrization.
-name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any]]]()
+name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any, Any]]]()
 
 
 @final
@@ -1271,7 +1271,7 @@ def parametrize(
         if node is None:
             name2pseudofixturedef = None
         else:
-            default: dict[str, FixtureDef[Any]] = {}
+            default: dict[str, FixtureDef[Any, Any]] = {}
             name2pseudofixturedef = node.stash.setdefault(
                 name2pseudofixturedef_key, default
             )
@@ -1458,7 +1458,7 @@ def _recompute_direct_params_indices(self) -> None:
 
 def _find_parametrized_scope(
     argnames: Sequence[str],
-    arg2fixturedefs: Mapping[str, Sequence[fixtures.FixtureDef[object]]],
+    arg2fixturedefs: Mapping[str, Sequence[fixtures.FixtureDef[Any, object]]],
     indirect: bool | Sequence[str],
 ) -> Scope:
     """Find the most appropriate scope for a parametrized call based on its arguments.
diff --git a/src/_pytest/setuponly.py b/src/_pytest/setuponly.py
index 1e887a896f5..ed09c83732d 100644
--- a/src/_pytest/setuponly.py
+++ b/src/_pytest/setuponly.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from collections.abc import Generator
+from typing import Any
 
 from _pytest._io.saferepr import saferepr
 from _pytest.config import Config
@@ -30,7 +31,7 @@ def pytest_addoption(parser: Parser) -> None:
 
 @pytest.hookimpl(wrapper=True)
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[object], request: SubRequest
+    fixturedef: FixtureDef[Any, object], request: SubRequest
 ) -> Generator[None, object, object]:
     try:
         return (yield)
@@ -51,7 +52,7 @@ def pytest_fixture_setup(
 
 
 def pytest_fixture_post_finalizer(
-    fixturedef: FixtureDef[object], request: SubRequest
+    fixturedef: FixtureDef[Any, object], request: SubRequest
 ) -> None:
     if fixturedef.cached_result is not None:
         config = request.config
@@ -62,7 +63,7 @@ def pytest_fixture_post_finalizer(
 
 
 def _show_fixture_action(
-    fixturedef: FixtureDef[object], config: Config, msg: str
+    fixturedef: FixtureDef[Any, object], config: Config, msg: str
 ) -> None:
     capman = config.pluginmanager.getplugin("capturemanager")
     if capman:
diff --git a/src/_pytest/setupplan.py b/src/_pytest/setupplan.py
index 4e124cce243..0a6f2f668e5 100644
--- a/src/_pytest/setupplan.py
+++ b/src/_pytest/setupplan.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Any
+
 from _pytest.config import Config
 from _pytest.config import ExitCode
 from _pytest.config.argparsing import Parser
@@ -21,7 +23,7 @@ def pytest_addoption(parser: Parser) -> None:
 
 @pytest.hookimpl(tryfirst=True)
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[object], request: SubRequest
+    fixturedef: FixtureDef[Any, object], request: SubRequest
 ) -> object | None:
     # Will return a dummy fixture if the setuponly option is provided.
     if request.config.option.setupplan:
diff --git a/testing/python/metafunc.py b/testing/python/metafunc.py
index 4e7e441768c..09ea1e451f9 100644
--- a/testing/python/metafunc.py
+++ b/testing/python/metafunc.py
@@ -32,7 +32,7 @@ def Metafunc(self, func, config=None) -> python.Metafunc:
         # on the funcarg level, so we don't need a full blown
         # initialization.
         class FuncFixtureInfoMock:
-            name2fixturedefs: dict[str, list[fixtures.FixtureDef[object]]] = {}
+            name2fixturedefs: dict[str, list[fixtures.FixtureDef[Any, object]]] = {}
 
             def __init__(self, names):
                 self.names_closure = names
@@ -153,7 +153,7 @@ class DummyFixtureDef:
             _scope: Scope
 
         fixtures_defs = cast(
-            dict[str, Sequence[fixtures.FixtureDef[object]]],
+            dict[str, Sequence[fixtures.FixtureDef[Any, object]]],
             dict(
                 session_fix=[DummyFixtureDef(Scope.Session)],
                 package_fix=[DummyFixtureDef(Scope.Package)],

From af0d67a5aa94dfa386f46454a8a349032086ca5b Mon Sep 17 00:00:00 2001
From: Bruno Oliveira <bruno@pytest.org>
Date: Sat, 7 Dec 2024 19:37:14 -0300
Subject: [PATCH 2/4] Use instance/owner for __get__

---
 src/_pytest/fixtures.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/_pytest/fixtures.py b/src/_pytest/fixtures.py
index 3a4b6fe5e62..451fbd2a5da 100644
--- a/src/_pytest/fixtures.py
+++ b/src/_pytest/fixtures.py
@@ -1263,13 +1263,13 @@ def __repr__(self) -> str:
         return f"<pytest_fixture({self._fixture_function})>"
 
     def __get__(
-        self, obj: object, objtype: type | None = None
+        self, instance: object, owner: type | None = None
     ) -> FixtureFunctionDefinition[FixtureParams, FixtureValue]:
         """Behave like a method if the function it was applied to was a method."""
         return FixtureFunctionDefinition(
             function=self._fixture_function,
             fixture_function_marker=self._fixture_function_marker,
-            instance=obj,
+            instance=instance,
             _ispytest=True,
         )
 

From 9f78c6c45bafe01dc8b05e1d8ab5905c39f063a8 Mon Sep 17 00:00:00 2001
From: Bruno Oliveira <bruno@pytest.org>
Date: Sat, 7 Dec 2024 19:42:16 -0300
Subject: [PATCH 3/4] Revert FixtureDef to a single argument

---
 src/_pytest/fixtures.py    | 54 ++++++++++++++++++--------------------
 src/_pytest/hookspec.py    |  4 +--
 src/_pytest/python.py      |  6 ++---
 src/_pytest/setuponly.py   |  7 +++--
 src/_pytest/setupplan.py   |  4 +--
 testing/python/metafunc.py |  4 +--
 6 files changed, 36 insertions(+), 43 deletions(-)

diff --git a/src/_pytest/fixtures.py b/src/_pytest/fixtures.py
index 451fbd2a5da..1b301b125b4 100644
--- a/src/_pytest/fixtures.py
+++ b/src/_pytest/fixtures.py
@@ -131,7 +131,7 @@ def pytest_sessionstart(session: Session) -> None:
 
 def get_scope_package(
     node: nodes.Item,
-    fixturedef: FixtureDef[Any, object],
+    fixturedef: FixtureDef[object],
 ) -> nodes.Node | None:
     from _pytest.python import Package
 
@@ -328,7 +328,7 @@ class FuncFixtureInfo:
     # matching the name which are applicable to this function.
     # There may be multiple overriding fixtures with the same name. The
     # sequence is ordered from furthest to closes to the function.
-    name2fixturedefs: dict[str, Sequence[FixtureDef[Any, Any]]]
+    name2fixturedefs: dict[str, Sequence[FixtureDef[Any]]]
 
     def prune_dependency_tree(self) -> None:
         """Recompute names_closure from initialnames and name2fixturedefs.
@@ -369,8 +369,8 @@ def __init__(
         self,
         pyfuncitem: Function,
         fixturename: str | None,
-        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any, Any]]],
-        fixture_defs: dict[str, FixtureDef[Any, Any]],
+        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]],
+        fixture_defs: dict[str, FixtureDef[Any]],
         *,
         _ispytest: bool = False,
     ) -> None:
@@ -413,7 +413,7 @@ def scope(self) -> _ScopeName:
     @abc.abstractmethod
     def _check_scope(
         self,
-        requested_fixturedef: FixtureDef[Any, object] | PseudoFixtureDef[object],
+        requested_fixturedef: FixtureDef[object] | PseudoFixtureDef[object],
         requested_scope: Scope,
     ) -> None:
         raise NotImplementedError()
@@ -554,7 +554,7 @@ def _iter_chain(self) -> Iterator[SubRequest]:
 
     def _get_active_fixturedef(
         self, argname: str
-    ) -> FixtureDef[Any, object] | PseudoFixtureDef[object]:
+    ) -> FixtureDef[object] | PseudoFixtureDef[object]:
         if argname == "request":
             cached_result = (self, [0], None)
             return PseudoFixtureDef(cached_result, Scope.Function)
@@ -626,9 +626,7 @@ def _get_active_fixturedef(
         self._fixture_defs[argname] = fixturedef
         return fixturedef
 
-    def _check_fixturedef_without_param(
-        self, fixturedef: FixtureDef[Any, object]
-    ) -> None:
+    def _check_fixturedef_without_param(self, fixturedef: FixtureDef[object]) -> None:
         """Check that this request is allowed to execute this fixturedef without
         a param."""
         funcitem = self._pyfuncitem
@@ -661,7 +659,7 @@ def _check_fixturedef_without_param(
             )
             fail(msg, pytrace=False)
 
-    def _get_fixturestack(self) -> list[FixtureDef[Any, Any]]:
+    def _get_fixturestack(self) -> list[FixtureDef[Any]]:
         values = [request._fixturedef for request in self._iter_chain()]
         values.reverse()
         return values
@@ -686,7 +684,7 @@ def _scope(self) -> Scope:
 
     def _check_scope(
         self,
-        requested_fixturedef: FixtureDef[Any, object] | PseudoFixtureDef[object],
+        requested_fixturedef: FixtureDef[object] | PseudoFixtureDef[object],
         requested_scope: Scope,
     ) -> None:
         # TopRequest always has function scope so always valid.
@@ -720,7 +718,7 @@ def __init__(
         scope: Scope,
         param: Any,
         param_index: int,
-        fixturedef: FixtureDef[Any, object],
+        fixturedef: FixtureDef[object],
         *,
         _ispytest: bool = False,
     ) -> None:
@@ -733,7 +731,7 @@ def __init__(
         )
         self._parent_request: Final[FixtureRequest] = request
         self._scope_field: Final = scope
-        self._fixturedef: Final[FixtureDef[Any, object]] = fixturedef
+        self._fixturedef: Final[FixtureDef[object]] = fixturedef
         if param is not NOTSET:
             self.param = param
         self.param_index: Final = param_index
@@ -763,7 +761,7 @@ def node(self):
 
     def _check_scope(
         self,
-        requested_fixturedef: FixtureDef[Any, object] | PseudoFixtureDef[object],
+        requested_fixturedef: FixtureDef[object] | PseudoFixtureDef[object],
         requested_scope: Scope,
     ) -> None:
         if isinstance(requested_fixturedef, PseudoFixtureDef):
@@ -784,7 +782,7 @@ def _check_scope(
                 pytrace=False,
             )
 
-    def _format_fixturedef_line(self, fixturedef: FixtureDef[Any, object]) -> str:
+    def _format_fixturedef_line(self, fixturedef: FixtureDef[object]) -> str:
         factory = fixturedef.func
         path, lineno = getfslineno(factory)
         if isinstance(path, Path):
@@ -959,11 +957,9 @@ def _eval_scope_callable(
 
 
 @final
-class FixtureDef(Generic[FixtureParams, FixtureValue]):
+class FixtureDef(Generic[FixtureValue]):
     """A container for a fixture definition.
 
-    This is a generic class parametrized on the parameters that a fixture function receives and its return value.
-
     Note: At this time, only explicitly documented fields and methods are
     considered public stable API.
     """
@@ -973,7 +969,7 @@ def __init__(
         config: Config,
         baseid: str | None,
         argname: str,
-        func: _FixtureFunc[FixtureParams, FixtureValue],
+        func: _FixtureFunc[Any, FixtureValue],
         scope: Scope | _ScopeName | Callable[[str, Config], _ScopeName] | None,
         params: Sequence[object] | None,
         ids: tuple[object | None, ...] | Callable[[Any], object | None] | None = None,
@@ -1128,8 +1124,8 @@ def __repr__(self) -> str:
 
 
 def resolve_fixture_function(
-    fixturedef: FixtureDef[FixtureParams, FixtureValue], request: FixtureRequest
-) -> _FixtureFunc[FixtureParams, FixtureValue]:
+    fixturedef: FixtureDef[FixtureValue], request: FixtureRequest
+) -> _FixtureFunc[Any, FixtureValue]:
     """Get the actual callable that can be called to obtain the fixture
     value."""
     fixturefunc = fixturedef.func
@@ -1152,7 +1148,7 @@ def resolve_fixture_function(
 
 
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[FixtureParams, FixtureValue], request: SubRequest
+    fixturedef: FixtureDef[FixtureValue], request: SubRequest
 ) -> FixtureValue:
     """Execution of fixture setup."""
     kwargs = {}
@@ -1525,7 +1521,7 @@ def __init__(self, session: Session) -> None:
         # suite/plugins defined with this name. Populated by parsefactories().
         # TODO: The order of the FixtureDefs list of each arg is significant,
         #       explain.
-        self._arg2fixturedefs: Final[dict[str, list[FixtureDef[Any, Any]]]] = {}
+        self._arg2fixturedefs: Final[dict[str, list[FixtureDef[Any]]]] = {}
         self._holderobjseen: Final[set[object]] = set()
         # A mapping from a nodeid to a list of autouse fixtures it defines.
         self._nodeid_autousenames: Final[dict[str, list[str]]] = {
@@ -1616,7 +1612,7 @@ def getfixtureclosure(
         parentnode: nodes.Node,
         initialnames: tuple[str, ...],
         ignore_args: AbstractSet[str],
-    ) -> tuple[list[str], dict[str, Sequence[FixtureDef[Any, Any]]]]:
+    ) -> tuple[list[str], dict[str, Sequence[FixtureDef[Any]]]]:
         # Collect the closure of all fixtures, starting with the given
         # fixturenames as the initial set.  As we have to visit all
         # factory definitions anyway, we also return an arg2fixturedefs
@@ -1626,7 +1622,7 @@ def getfixtureclosure(
 
         fixturenames_closure = list(initialnames)
 
-        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any, Any]]] = {}
+        arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]] = {}
         lastlen = -1
         while lastlen != len(fixturenames_closure):
             lastlen = len(fixturenames_closure)
@@ -1841,7 +1837,7 @@ def parsefactories(
 
     def getfixturedefs(
         self, argname: str, node: nodes.Node
-    ) -> Sequence[FixtureDef[Any, Any]] | None:
+    ) -> Sequence[FixtureDef[Any]] | None:
         """Get FixtureDefs for a fixture name which are applicable
         to a given node.
 
@@ -1860,8 +1856,8 @@ def getfixturedefs(
         return tuple(self._matchfactories(fixturedefs, node))
 
     def _matchfactories(
-        self, fixturedefs: Iterable[FixtureDef[Any, Any]], node: nodes.Node
-    ) -> Iterator[FixtureDef[Any, Any]]:
+        self, fixturedefs: Iterable[FixtureDef[Any]], node: nodes.Node
+    ) -> Iterator[FixtureDef[Any]]:
         parentnodeids = {n.nodeid for n in node.iter_parents()}
         for fixturedef in fixturedefs:
             if fixturedef.baseid in parentnodeids:
@@ -1898,7 +1894,7 @@ def get_best_relpath(func) -> str:
         loc = getlocation(func, invocation_dir)
         return bestrelpath(invocation_dir, Path(loc))
 
-    def write_fixture(fixture_def: FixtureDef[Any, object]) -> None:
+    def write_fixture(fixture_def: FixtureDef[object]) -> None:
         argname = fixture_def.argname
         if verbose <= 0 and argname.startswith("_"):
             return
diff --git a/src/_pytest/hookspec.py b/src/_pytest/hookspec.py
index 66700a3938b..8b20061d6f0 100644
--- a/src/_pytest/hookspec.py
+++ b/src/_pytest/hookspec.py
@@ -866,7 +866,7 @@ def pytest_report_from_serializable(
 
 @hookspec(firstresult=True)
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[Any, Any], request: SubRequest
+    fixturedef: FixtureDef[Any], request: SubRequest
 ) -> object | None:
     """Perform fixture setup execution.
 
@@ -894,7 +894,7 @@ def pytest_fixture_setup(
 
 
 def pytest_fixture_post_finalizer(
-    fixturedef: FixtureDef[Any, Any], request: SubRequest
+    fixturedef: FixtureDef[Any], request: SubRequest
 ) -> None:
     """Called after fixture teardown, but before the cache is cleared, so
     the fixture result ``fixturedef.cached_result`` is still available (not
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index c8db81e73c9..85e3cb0ae71 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -1085,7 +1085,7 @@ def get_direct_param_fixture_func(request: FixtureRequest) -> Any:
 
 
 # Used for storing pseudo fixturedefs for direct parametrization.
-name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any, Any]]]()
+name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any]]]()
 
 
 @final
@@ -1271,7 +1271,7 @@ def parametrize(
         if node is None:
             name2pseudofixturedef = None
         else:
-            default: dict[str, FixtureDef[Any, Any]] = {}
+            default: dict[str, FixtureDef[Any]] = {}
             name2pseudofixturedef = node.stash.setdefault(
                 name2pseudofixturedef_key, default
             )
@@ -1458,7 +1458,7 @@ def _recompute_direct_params_indices(self) -> None:
 
 def _find_parametrized_scope(
     argnames: Sequence[str],
-    arg2fixturedefs: Mapping[str, Sequence[fixtures.FixtureDef[Any, object]]],
+    arg2fixturedefs: Mapping[str, Sequence[fixtures.FixtureDef[object]]],
     indirect: bool | Sequence[str],
 ) -> Scope:
     """Find the most appropriate scope for a parametrized call based on its arguments.
diff --git a/src/_pytest/setuponly.py b/src/_pytest/setuponly.py
index ed09c83732d..1e887a896f5 100644
--- a/src/_pytest/setuponly.py
+++ b/src/_pytest/setuponly.py
@@ -1,7 +1,6 @@
 from __future__ import annotations
 
 from collections.abc import Generator
-from typing import Any
 
 from _pytest._io.saferepr import saferepr
 from _pytest.config import Config
@@ -31,7 +30,7 @@ def pytest_addoption(parser: Parser) -> None:
 
 @pytest.hookimpl(wrapper=True)
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[Any, object], request: SubRequest
+    fixturedef: FixtureDef[object], request: SubRequest
 ) -> Generator[None, object, object]:
     try:
         return (yield)
@@ -52,7 +51,7 @@ def pytest_fixture_setup(
 
 
 def pytest_fixture_post_finalizer(
-    fixturedef: FixtureDef[Any, object], request: SubRequest
+    fixturedef: FixtureDef[object], request: SubRequest
 ) -> None:
     if fixturedef.cached_result is not None:
         config = request.config
@@ -63,7 +62,7 @@ def pytest_fixture_post_finalizer(
 
 
 def _show_fixture_action(
-    fixturedef: FixtureDef[Any, object], config: Config, msg: str
+    fixturedef: FixtureDef[object], config: Config, msg: str
 ) -> None:
     capman = config.pluginmanager.getplugin("capturemanager")
     if capman:
diff --git a/src/_pytest/setupplan.py b/src/_pytest/setupplan.py
index 0a6f2f668e5..4e124cce243 100644
--- a/src/_pytest/setupplan.py
+++ b/src/_pytest/setupplan.py
@@ -1,7 +1,5 @@
 from __future__ import annotations
 
-from typing import Any
-
 from _pytest.config import Config
 from _pytest.config import ExitCode
 from _pytest.config.argparsing import Parser
@@ -23,7 +21,7 @@ def pytest_addoption(parser: Parser) -> None:
 
 @pytest.hookimpl(tryfirst=True)
 def pytest_fixture_setup(
-    fixturedef: FixtureDef[Any, object], request: SubRequest
+    fixturedef: FixtureDef[object], request: SubRequest
 ) -> object | None:
     # Will return a dummy fixture if the setuponly option is provided.
     if request.config.option.setupplan:
diff --git a/testing/python/metafunc.py b/testing/python/metafunc.py
index 09ea1e451f9..4e7e441768c 100644
--- a/testing/python/metafunc.py
+++ b/testing/python/metafunc.py
@@ -32,7 +32,7 @@ def Metafunc(self, func, config=None) -> python.Metafunc:
         # on the funcarg level, so we don't need a full blown
         # initialization.
         class FuncFixtureInfoMock:
-            name2fixturedefs: dict[str, list[fixtures.FixtureDef[Any, object]]] = {}
+            name2fixturedefs: dict[str, list[fixtures.FixtureDef[object]]] = {}
 
             def __init__(self, names):
                 self.names_closure = names
@@ -153,7 +153,7 @@ class DummyFixtureDef:
             _scope: Scope
 
         fixtures_defs = cast(
-            dict[str, Sequence[fixtures.FixtureDef[Any, object]]],
+            dict[str, Sequence[fixtures.FixtureDef[object]]],
             dict(
                 session_fix=[DummyFixtureDef(Scope.Session)],
                 package_fix=[DummyFixtureDef(Scope.Package)],

From 348068ccad91074ddcc8f26f3c4412afcbf66c6f Mon Sep 17 00:00:00 2001
From: Bruno Oliveira <bruno@pytest.org>
Date: Sat, 7 Dec 2024 19:45:34 -0300
Subject: [PATCH 4/4] Add FixtureDefDict type alias

---
 src/_pytest/fixtures.py | 5 ++++-
 src/_pytest/python.py   | 5 +++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/_pytest/fixtures.py b/src/_pytest/fixtures.py
index 1b301b125b4..454a1e52a6c 100644
--- a/src/_pytest/fixtures.py
+++ b/src/_pytest/fixtures.py
@@ -95,6 +95,9 @@
 # The parameters that a fixture function receives.
 FixtureParams = ParamSpec("FixtureParams")
 
+# A dict of fixture name -> its FixtureDef.
+FixtureDefDict: TypeAlias = dict[str, "FixtureDef[Any]"]
+
 # The type of fixture function (type alias generic in fixture params and value).
 _FixtureFunc: TypeAlias = Union[
     Callable[FixtureParams, FixtureValue],
@@ -370,7 +373,7 @@ def __init__(
         pyfuncitem: Function,
         fixturename: str | None,
         arg2fixturedefs: dict[str, Sequence[FixtureDef[Any]]],
-        fixture_defs: dict[str, FixtureDef[Any]],
+        fixture_defs: FixtureDefDict,
         *,
         _ispytest: bool = False,
     ) -> None:
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index 85e3cb0ae71..f17a696799a 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -51,6 +51,7 @@
 from _pytest.config.argparsing import Parser
 from _pytest.deprecated import check_ispytest
 from _pytest.fixtures import FixtureDef
+from _pytest.fixtures import FixtureDefDict
 from _pytest.fixtures import FixtureRequest
 from _pytest.fixtures import FuncFixtureInfo
 from _pytest.fixtures import get_scope_node
@@ -1085,7 +1086,7 @@ def get_direct_param_fixture_func(request: FixtureRequest) -> Any:
 
 
 # Used for storing pseudo fixturedefs for direct parametrization.
-name2pseudofixturedef_key = StashKey[dict[str, FixtureDef[Any]]]()
+name2pseudofixturedef_key = StashKey[FixtureDefDict]()
 
 
 @final
@@ -1271,7 +1272,7 @@ def parametrize(
         if node is None:
             name2pseudofixturedef = None
         else:
-            default: dict[str, FixtureDef[Any]] = {}
+            default: FixtureDefDict = {}
             name2pseudofixturedef = node.stash.setdefault(
                 name2pseudofixturedef_key, default
             )