Default free threaded off

Signed-off-by: Bernát Gábor <[email protected]>

Author: gaborbernat

.github/workflows/check.yaml

@@ -23,6 +23,7 @@ jobs:
       fail-fast: false
       matrix:
         py:
+          - "3.14t"
           - "3.14"
           - "3.13"
           - "3.12"
@@ -51,6 +52,8 @@ jobs:
         run: uv tool install --python-preference only-managed --python ${{ matrix.py }} tox@.
       - name: Setup test suite
         run: tox run -vv --notest --skip-missing-interpreters false -e ${{ matrix.py }}
+        env:
+          PYTHON_GIL: ${{ !endsWith(matrix.py, 't') }}
       - name: Run test suite
         run: tox run --skip-pkg-install -e ${{ matrix.py }}
         env:

docs/config.rst

@@ -542,8 +542,10 @@ Base options
             - ✅
             - ✅
             - ❌
-
-
+       *   - PYTHON_GIL
+            - ✅
+            - ✅
+            - ✅
 
    More environment variable-related information
    can be found in :ref:`environment variable substitutions`.
@@ -834,6 +836,7 @@ Python options
    Python version for a tox environment. If not specified, the virtual environments factors (e.g. name part) will be
    used to automatically set one. For example, ``py310`` means ``python3.10``, ``py3`` means ``python3`` and ``py``
    means ``python``. If the name does not match this pattern the same Python version tox is installed into will be used.
+   A base interpreter ending with ``t`` means that only free threaded Python implementations are accepted.
 
     .. versionchanged:: 3.1
 

src/tox/tox_env/api.py

@@ -222,6 +222,7 @@ def _default_pass_env(self) -> list[str]:  # noqa: PLR6301
             "FORCE_COLOR",  # force color output
             "NO_COLOR",  # disable color output
             "NETRC",  # used by pip and netrc modules
+            "PYTHON_GIL",  # allows controlling python gil
         ]
         if sys.stdout.isatty():  # if we're on a interactive shell pass on the TERM
             env.append("TERM")

src/tox/tox_env/python/api.py

@@ -7,8 +7,9 @@
 import sys
 import sysconfig
 from abc import ABC, abstractmethod
+from dataclasses import dataclass
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, List, NamedTuple, cast
+from typing import TYPE_CHECKING, Any, List, NamedTuple
 
 from virtualenv.discovery.py_spec import PythonSpec
 
@@ -27,14 +28,15 @@ class VersionInfo(NamedTuple):
     serial: int
 
 
-class PythonInfo(NamedTuple):
+@dataclass(frozen=True)
+class PythonInfo:
     implementation: str
     version_info: VersionInfo
     version: str
-    free_threaded: bool
     is_64: bool
     platform: str
     extra: dict[str, Any]
+    free_threaded: bool = False
 
     @property
     def version_no_dot(self) -> str:
@@ -300,7 +302,7 @@ def base_python(self) -> PythonInfo:
                 raise Skip(msg)
             raise NoInterpreter(base_pythons)
 
-        return cast("PythonInfo", self._base_python)
+        return self._base_python
 
     def _get_env_journal_python(self) -> dict[str, Any]:
         return {

src/tox/tox_env/python/virtual_env/api.py

@@ -143,10 +143,10 @@ def _get_python(self, base_python: list[str]) -> PythonInfo | None:  # noqa: ARG
             implementation=interpreter.implementation,
             version_info=interpreter.version_info,
             version=interpreter.version,
-            free_threaded=interpreter.free_threaded,
             is_64=(interpreter.architecture == 64),  # noqa: PLR2004
             platform=interpreter.platform,
             extra={"executable": Path(interpreter.system_executable).resolve()},
+            free_threaded=interpreter.free_threaded,
         )
 
     def prepend_env_var_path(self) -> list[Path]:

tests/conftest.py

@@ -2,6 +2,7 @@
 
 import os
 import sys
+import sysconfig
 from pathlib import Path
 from typing import TYPE_CHECKING, Callable, Iterator, Protocol, Sequence
 from unittest.mock import patch
@@ -97,10 +98,10 @@ def get_python(self: VirtualEnv, base_python: list[str]) -> PythonInfo | None:
                 implementation=impl,
                 version_info=ver_info,
                 version="",
-                free_threaded=False,
                 is_64=True,
                 platform=sys.platform,
                 extra={"executable": Path(sys.executable)},
+                free_threaded=sysconfig.get_config_var("Py_GIL_DISABLED") == 1,
             )
 
         mocker.patch.object(VirtualEnv, "_get_python", get_python)

tests/session/cmd/test_show_config.py

@@ -135,7 +135,7 @@ def test_pass_env_config_default(tox_project: ToxProjectCreator, stdout_is_atty:
         + (["PROGRAMDATA"] if is_win else [])
         + (["PROGRAMFILES"] if is_win else [])
         + (["PROGRAMFILES(x86)"] if is_win else [])
-        + ["REQUESTS_CA_BUNDLE", "SSL_CERT_FILE"]
+        + ["PYTHON_GIL", "REQUESTS_CA_BUNDLE", "SSL_CERT_FILE"]
         + (["SYSTEMDRIVE", "SYSTEMROOT", "TEMP"] if is_win else [])
         + (["TERM"] if stdout_is_atty else [])
         + (["TMP", "USERPROFILE"] if is_win else ["TMPDIR"])

tox.toml

@@ -1,5 +1,5 @@
 requires = ["tox>=4.24.1"]
-env_list = ["fix", "3.14", "3.13", "3.12", "3.11", "3.10", "3.9", "cov", "type", "docs", "pkg_meta"]
+env_list = ["fix", "3.14t", "3.14", "3.13", "3.12", "3.11", "3.10", "3.9", "cov", "type", "docs", "pkg_meta"]
 skip_missing_interpreters = true
 
 [env_run_base]