Drop support for positional arguments in @pytest.fixture

changelog/5585.breaking.rst

@@ -2,3 +2,5 @@ As per our policy, the following features have been deprecated in the 5.X series
 removed:
 
 * The ``funcargnames`` read-only property of ``FixtureRequest``, ``Metafunc``, and ``Function`` classes. Use ``fixturenames`` attribute.
+
+* ``@pytest.fixture`` no longer supports positional arguments, pass all arguments by keyword instead.

doc/en/deprecations.rst

@@ -162,6 +162,13 @@ Removed Features
 As stated in our :ref:`backwards-compatibility` policy, deprecated features are removed only in major releases after
 an appropriate period of deprecation has passed.
 
+``pytest.fixture`` arguments are keyword only
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. versionremoved:: 6.0
+
+Passing arguments to pytest.fixture() as positional arguments has been removed - pass them by keyword instead.
+
 ``funcargnames`` alias for ``fixturenames``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

src/_pytest/deprecated.py

@@ -30,11 +30,6 @@ RESULT_LOG = PytestDeprecationWarning(
     "See https://docs.pytest.org/en/stable/deprecations.html#result-log-result-log for more information."
 )
 
-FIXTURE_POSITIONAL_ARGUMENTS = PytestDeprecationWarning(
-    "Passing arguments to pytest.fixture() as positional arguments is deprecated - pass them "
-    "as a keyword argument instead."
-)
-
 NODE_USE_FROM_PARENT = UnformattedWarning(
     PytestDeprecationWarning,
     "Direct construction of {name} has been deprecated, please use {name}.from_parent.\n"

src/_pytest/fixtures.py

@@ -2,7 +2,6 @@ import functools
 import inspect
 import os
 import sys
-import warnings
 from collections import defaultdict
 from collections import deque
 from types import TracebackType
@@ -46,7 +45,6 @@ from _pytest.compat import TYPE_CHECKING
 from _pytest.config import _PluggyPlugin
 from _pytest.config import Config
 from _pytest.config.argparsing import Parser
-from _pytest.deprecated import FIXTURE_POSITIONAL_ARGUMENTS
 from _pytest.mark import ParameterSet
 from _pytest.outcomes import fail
 from _pytest.outcomes import TEST_OUTCOME
@@ -1246,7 +1244,7 @@ def fixture(  # noqa: F811
 
 def fixture(  # noqa: F811
     fixture_function: Optional[_FixtureFunction] = None,
-    *args: Any,
+    *,
     scope: "Union[_Scope, Callable[[str, Config], _Scope]]" = "function",
     params: Optional[Iterable[object]] = None,
     autouse: bool = False,
@@ -1308,53 +1306,6 @@ def fixture(  # noqa: F811
         name the decorated function ``fixture_<fixturename>`` and then use
         ``@pytest.fixture(name='<fixturename>')``.
     """
-    # Positional arguments backward compatibility.
-    # If a kwarg is equal to its default, assume it was not explicitly
-    # passed, i.e. not duplicated. The more correct way is to use a
-    # **kwargs and check `in`, but that obfuscates the function signature.
-    if isinstance(fixture_function, str):
-        # It's actually the first positional argument, scope.
-        args = (fixture_function, *args)  # type: ignore[unreachable]
-        fixture_function = None
-    duplicated_args = []
-    if len(args) > 0:
-        if scope == "function":
-            scope = args[0]
-        else:
-            duplicated_args.append("scope")
-    if len(args) > 1:
-        if params is None:
-            params = args[1]
-        else:
-            duplicated_args.append("params")
-    if len(args) > 2:
-        if autouse is False:
-            autouse = args[2]
-        else:
-            duplicated_args.append("autouse")
-    if len(args) > 3:
-        if ids is None:
-            ids = args[3]
-        else:
-            duplicated_args.append("ids")
-    if len(args) > 4:
-        if name is None:
-            name = args[4]
-        else:
-            duplicated_args.append("name")
-    if len(args) > 5:
-        raise TypeError(
-            "fixture() takes 5 positional arguments but {} were given".format(len(args))
-        )
-    if duplicated_args:
-        raise TypeError(
-            "The fixture arguments are defined as positional and keyword: {}. "
-            "Use only keyword arguments.".format(", ".join(duplicated_args))
-        )
-    if args:
-        warnings.warn(FIXTURE_POSITIONAL_ARGUMENTS, stacklevel=2)
-    # End backward compatiblity.
-
     fixture_marker = FixtureFunctionMarker(
         scope=scope, params=params, autouse=autouse, ids=ids, name=name,
     )

testing/python/fixtures.py

@@ -4130,73 +4130,6 @@ def test_fixture_named_request(testdir):
     )
 
 
-def test_fixture_duplicated_arguments() -> None:
-    """Raise error if there are positional and keyword arguments for the same parameter (#1682)."""
-    with pytest.raises(TypeError) as excinfo:
-
-        @pytest.fixture("session", scope="session")  # type: ignore[call-overload]
-        def arg(arg):
-            pass
-
-    assert (
-        str(excinfo.value)
-        == "The fixture arguments are defined as positional and keyword: scope. "
-        "Use only keyword arguments."
-    )
-
-    with pytest.raises(TypeError) as excinfo:
-
-        @pytest.fixture(  # type: ignore[call-overload]
-            "function",
-            ["p1"],
-            True,
-            ["id1"],
-            "name",
-            scope="session",
-            params=["p1"],
-            autouse=True,
-            ids=["id1"],
-            name="name",
-        )
-        def arg2(request):
-            pass
-
-    assert (
-        str(excinfo.value)
-        == "The fixture arguments are defined as positional and keyword: scope, params, autouse, ids, name. "
-        "Use only keyword arguments."
-    )
-
-
-def test_fixture_with_positionals() -> None:
-    """Raise warning, but the positionals should still works (#1682)."""
-    from _pytest.deprecated import FIXTURE_POSITIONAL_ARGUMENTS
-
-    with pytest.warns(pytest.PytestDeprecationWarning) as warnings:
-
-        @pytest.fixture("function", [0], True)  # type: ignore[call-overload]
-        def fixture_with_positionals():
-            pass
-
-    assert str(warnings[0].message) == str(FIXTURE_POSITIONAL_ARGUMENTS)
-
-    assert fixture_with_positionals._pytestfixturefunction.scope == "function"
-    assert fixture_with_positionals._pytestfixturefunction.params == (0,)
-    assert fixture_with_positionals._pytestfixturefunction.autouse
-
-
-def test_fixture_with_too_many_positionals() -> None:
-    with pytest.raises(TypeError) as excinfo:
-
-        @pytest.fixture("function", [0], True, ["id"], "name", "extra")  # type: ignore[call-overload]
-        def fixture_with_positionals():
-            pass
-
-    assert (
-        str(excinfo.value) == "fixture() takes 5 positional arguments but 6 were given"
-    )
-
-
 def test_indirect_fixture_does_not_break_scope(testdir):
     """Ensure that fixture scope is respected when using indirect fixtures (#570)"""
     testdir.makepyfile(