Implement support for the free-threaded build of CPython 3.13 (#84)

Co-authored-by: Sam Bull <git@sambull.org>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: J. Nick Koston <nick@koston.org>

.github/workflows/ci-cd.yml

@@ -191,6 +191,7 @@ jobs:
     strategy:
       matrix:
         pyver:
+        - 3.13t
         - 3.13
         - 3.12
         - 3.11
@@ -238,9 +239,11 @@ 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
@@ -257,7 +260,7 @@ jobs:
     - name: Install dependencies
       uses: py-actions/py-dependency-install@v4
       with:
-        path: requirements/test.txt
+        path: requirements/codspeed.txt
     - name: Determine pre-compiled compatible wheel
       env:
         # NOTE: When `pip` is forced to colorize output piped into `jq`,
@@ -419,7 +422,7 @@ jobs:
     - name: Install dependencies
       uses: py-actions/py-dependency-install@v4
       with:
-        path: requirements/test.txt
+        path: requirements/codspeed.txt
     - name: Determine pre-compiled compatible wheel
       env:
         # NOTE: When `pip` is forced to colorize output piped into `jq`,

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 +372,12 @@ 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'):
+        c_ext_build_deps = ['Cython ~= 3.1.0a1']
+    else:
+        c_ext_build_deps = ['Cython ~= 3.0.12']
 
     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
@@ -94,3 +95,12 @@ before-test = []  # Windows cmd has different syntax and pip chooses wheels
 
 [tool.cibuildwheel.linux]
 before-all = "yum install -y libffi-devel || apk add --upgrade libffi-dev || apt-get install libffi-dev"
+
+# TODO: Remove this when there's a Cython 3.1 final release
+# Remove PIP_CONSTRAINT from the environment
+[[tool.cibuildwheel.overrides]]
+select = "cp313t-*"
+
+test-requires = "-r requirements/test-freethreading.txt"
+inherit.environment = "append"
+environment = {PIP_CONSTRAINT = "requirements/cython-freethreading.txt"}

requirements/codspeed.txt

@@ -0,0 +1,2 @@
+-r test.txt
+pytest-codspeed==3.2.0

requirements/cython-freethreading.txt

@@ -0,0 +1 @@
+cython==3.1.0a1

requirements/dev.txt

@@ -1,2 +1,2 @@
--r test.txt
+-r codspeed.txt
 -r towncrier.txt

requirements/test-freethreading.txt

@@ -0,0 +1,2 @@
+-r cython-freethreading.txt
+-r test-pure.txt

requirements/test-pure.txt

@@ -0,0 +1,4 @@
+covdefaults
+pytest==8.3.4
+pytest-cov>=2.3.1
+pytest-xdist

requirements/test.txt

@@ -1,6 +1,2 @@
 -r cython.txt
-covdefaults
-pytest==8.3.4
-pytest-codspeed==3.2.0
-pytest-cov>=2.3.1
-pytest-xdist
+-r test-pure.txt

src/propcache/_helpers_c.pyx

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

tests/test_benchmarks.py

@@ -1,11 +1,16 @@
 """codspeed benchmarks for propcache."""
 
-from pytest_codspeed import BenchmarkFixture
+import pytest
+
+try:
+    from pytest_codspeed import BenchmarkFixture
+except ImportError:
+    pytestmark = pytest.mark.skip("pytest_codspeed needs to be installed")
 
 from propcache import cached_property, under_cached_property
 
 
-def test_under_cached_property_cache_hit(benchmark: BenchmarkFixture) -> None:
+def test_under_cached_property_cache_hit(benchmark: "BenchmarkFixture") -> None:
     """Benchmark for under_cached_property cache hit."""
 
     class Test:
@@ -25,7 +30,7 @@ def _run() -> None:
             t.prop
 
 
-def test_cached_property_cache_hit(benchmark: BenchmarkFixture) -> None:
+def test_cached_property_cache_hit(benchmark: "BenchmarkFixture") -> None:
     """Benchmark for cached_property cache hit."""
 
     class Test:
@@ -45,7 +50,7 @@ def _run() -> None:
             t.prop
 
 
-def test_under_cached_property_cache_miss(benchmark: BenchmarkFixture) -> None:
+def test_under_cached_property_cache_miss(benchmark: "BenchmarkFixture") -> None:
     """Benchmark for under_cached_property cache miss."""
 
     class Test:
@@ -67,7 +72,7 @@ def _run() -> None:
             t.prop
 
 
-def test_cached_property_cache_miss(benchmark: BenchmarkFixture) -> None:
+def test_cached_property_cache_miss(benchmark: "BenchmarkFixture") -> None:
     """Benchmark for cached_property cache miss."""
 
     class Test: