Add support for free-threaded builds (#70)

* Build free-threaded wheels, disable limited API there

Co-authored-by: Min RK <151929+minrk@users.noreply.github.com>

* Try installing libffi-dev on Linux

It's faling due to lack of includes. Presumably because the lack of cffi
wheels.

* Revert "Try installing libffi-dev on Linux"

Does not work.

* Merge

* Actually build FT

* support the free-threaded build of Python 3.14 (#93)

* support the free-threaded build of Python 3.14

* attempt to get 3.14t CI to run

* Add trove classifier

* Add changelog

* Add 3.14 trove classifier, too

---------

Co-authored-by: Hynek Schlawack <hs@ox.cx>

---------

Co-authored-by: Min RK <151929+minrk@users.noreply.github.com>
Co-authored-by: Nathan Goldbaum <nathan.goldbaum@gmail.com>

.github/workflows/ci.yml

@@ -29,6 +29,7 @@ jobs:
           - "3.12"
           - "3.13"
           - "3.14"
+          - "3.14t"
           - "pypy-3.9"
           - "pypy-3.10"
 
@@ -56,7 +57,7 @@ jobs:
 
           echo TOX_PYTHON=$V >>$GITHUB_ENV
 
-      - run: python -Im tox run -f $TOX_PYTHON
+      - run: python -Im tox run -e $TOX_PYTHON
 
   system-package:
     runs-on: ubuntu-latest

.github/workflows/wheels.yml

@@ -31,7 +31,7 @@ jobs:
           persist-credentials: false
 
       # See pyproject.toml for config.
-      - uses: pypa/cibuildwheel@v3.0
+      - uses: pypa/cibuildwheel@v3.1
 
       - uses: actions/upload-artifact@v4
         with:

CHANGELOG.md

@@ -25,6 +25,9 @@ Vendoring Argon2 @ [**`f57e61e`**](https://github.com/P-H-C/phc-winner-argon2/co
 - Official Python 3.12, 3.13, and 3.14 support.
   No code or packaging changes were necessary.
 
+- Support for free-threading (aka nogil) on Python 3.14.
+  [#93](https://github.com/hynek/argon2-cffi-bindings/pull/93)
+
 
 ### Removed
 

pyproject.toml

@@ -2,7 +2,8 @@
 requires = [
     "setuptools>=77",
     "setuptools_scm[toml]>=6.2",
-    "cffi>=1.0.1",
+    "cffi>=1.0.1; python_version < '3.14'",
+    "cffi>=2.0.0b1; python_version >= '3.14'",
 ]
 build-backend = "setuptools.build_meta"
 
@@ -30,13 +31,18 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: Free Threading",
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
     "Topic :: Security :: Cryptography",
     "Topic :: Security",
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]
-dependencies = ["cffi>=1.0.1"]
+dependencies = [
+    "cffi>=1.0.1; python_version < '3.14'",
+    "cffi>=2.0.0b1; python_version >= '3.14'",
+]
 
 [project.optional-dependencies]
 tests = ["pytest"]
@@ -61,6 +67,7 @@ local_scheme = "no-local-version"
 [tool.cibuildwheel]
 build =  [
     "cp39-*" ,  # We have portable abi3 wheels.
+    "cp314t-*", # Free-threading / nogil.
     "pp310-*",  # PyPy 3.9 is EOL and doesn't build on Windows anymore.
 ]
 enable = ["pypy"]

setup.py

@@ -2,6 +2,7 @@
 
 import platform
 import sys
+import sysconfig
 
 from setuptools import setup
 
@@ -17,7 +18,11 @@ if platform.python_implementation() == "CPython":
 
         class BDistWheel(bdist_wheel):
             def finalize_options(self):
-                self.py_limited_api = f"cp3{sys.version_info[1]}"
+                # Free-threaded CPython doesn't support limited API.
+                if sysconfig.get_config_var("Py_GIL_DISABLED"):
+                    self.py_limited_api = False
+                else:
+                    self.py_limited_api = f"cp3{sys.version_info[1]}"
 
                 super().finalize_options()
 

src/_argon2_cffi_bindings/_ffi_build.py

@@ -2,6 +2,7 @@
 
 import os
 import platform
+import sysconfig
 
 from pathlib import Path
 
@@ -11,6 +12,8 @@ from cffi import FFI
 use_system_argon2 = os.environ.get("ARGON2_CFFI_USE_SYSTEM", "0") == "1"
 use_sse2 = os.environ.get("ARGON2_CFFI_USE_SSE2", None)
 windows = platform.system() == "Windows"
+# Free-threaded CPython doesn't support limited API.
+limited_api = not sysconfig.get_config_var("Py_GIL_DISABLED")
 
 
 # Try to detect cross-compilation.
@@ -48,6 +51,7 @@ if use_system_argon2:
         "_ffi",
         "#include <argon2.h>",
         libraries=["argon2"],
+        py_limited_api=limited_api,
     )
 else:
     lib_base = Path("extras") / "libargon2" / "src"
@@ -56,6 +60,7 @@ else:
         "#include <argon2.h>",
         extra_compile_args=["-msse2"] if (optimized and not windows) else None,
         include_dirs=[str(Path("extras", "libargon2", "include"))],
+        py_limited_api=limited_api,
         sources=[
             str(lib_base / path)
             for path in [

tox.ini

@@ -10,7 +10,7 @@ min_version = 4
 env_list =
     pre-commit,
     cog-{check,render},
-    py3{9,10,11,12,13,14},
+    py3{9,10,11,12,13,14,14t},
     pypy3{9,10},
     system-argon2