Implement support for the free-threaded build of CPython 3.13

.github/workflows/ci-cd.yml

@@ -38,7 +38,7 @@ env:
   PY_COLORS: 1  # Recognized by the `py` package, dependency of `pytest`
   PYTHONIOENCODING: utf-8
   PYTHONUTF8: 1
-  PYTHON_LATEST: 3.12
+  PYTHON_LATEST: 3.13
 
 
 jobs:
@@ -184,6 +184,7 @@ jobs:
     strategy:
       matrix:
         pyver:
+        - 3.13t
         - 3.13
         - 3.12
         - 3.11
@@ -229,9 +230,11 @@ jobs:
         pattern: ${{ needs.pre-setup.outputs.dists-artifact-name }}*
         merge-multiple: true
 
+    # TODO: Revert back to using actions/setup-python once the official
+    # action supports free-threaded Python
     - name: Setup Python ${{ matrix.pyver }}
       id: python-install
-      uses: actions/setup-python@v5
+      uses: quansight-labs/setup-python@v5
       with:
         python-version: ${{ matrix.pyver }}
         allow-prereleases: true

.github/workflows/reusable-linters.yml

@@ -21,7 +21,7 @@ env:
   PY_COLORS: 1  # Recognized by the `py` package, dependency of `pytest`
   PYTHONIOENCODING: utf-8
   PYTHONUTF8: 1
-  PYTHON_LATEST: 3.12
+  PYTHON_LATEST: 3.13
 
 jobs:
 

CHANGES/84.feature.rst

@@ -0,0 +1 @@
+Implemented support for the free-threaded build of CPython 3.13 -- by :user:`lysnikolaou`.

CHANGES/84.packaging.rst

@@ -0,0 +1 @@
+Started building wheels for the free-threaded build of CPython 3.13 -- by :user:`lysnikolaou`.

docs/spelling_wordlist.txt

@@ -1,5 +1,6 @@
 Bluesky
 Bugfixes
+CPython
 Changelog
 Codecov
 Cython

packaging/pep517_backend/_backend.py

@@ -4,6 +4,7 @@
 from __future__ import annotations
 
 import os
+import sysconfig
 import typing as t
 from contextlib import contextmanager, nullcontext, suppress
 from functools import partial
@@ -371,10 +372,13 @@ def get_requires_for_build_wheel(
             stacklevel=999,
         )
 
-    c_ext_build_deps = [] if is_pure_python_build else [
-        'Cython ~= 3.0.0; python_version >= "3.12"',
-        'Cython; python_version < "3.12"',
-    ]
+    if is_pure_python_build:
+        c_ext_build_deps = []
+    elif sysconfig.get_config_var("Py_GIL_DISABLED"):
+        # TODO: Remove when there's a Cython final with free-threading support
+        c_ext_build_deps = ['Cython == 3.1.0a1']
+    else:
+        c_ext_build_deps = ['Cython ~= 3.0.0']
 
     return _setuptools_get_requires_for_build_wheel(
         config_settings=config_settings,

pyproject.toml

@@ -64,6 +64,7 @@ linetrace = "True"  # Implies `profile=True`
 
 [tool.cibuildwheel]
 build-frontend = "build"
+enable = ["cpython-freethreading"]
 before-test = [
   # NOTE: Attempt to have pip pre-compile PyYAML wheel with our build
   # NOTE: constraints unset. The hope is that pip will cache that wheel

requirements/cython.txt

@@ -1 +1,2 @@
-cython==3.0.11
+cython==3.0.11; python_version < '3.13'
+cython==3.1.0a1; python_version >= '3.13'

src/propcache/_helpers_c.pyx

@@ -1,4 +1,4 @@
-# cython: language_level=3
+# cython: language_level=3, freethreading_compatible=True
 from types import GenericAlias