build: use packaging.version.Version

This avoids a deprecation warning on the distutils class.

Author: indygreg

ci/conda/meta.yaml

@@ -10,6 +10,7 @@ source:
 requirements:
   build:
     - python
+    - packaging
     - setuptools
 
   run:

ci/requirements.in

@@ -1,2 +1,3 @@
 cffi
+packaging
 wheel

ci/requirements.txt

@@ -69,6 +69,10 @@ cffi==1.17.1 \
     --hash=sha256:f7f5baafcc48261359e14bcd6d9bff6d4b28d9103847c9e136694cb0501aef87 \
     --hash=sha256:fc48c783f9c87e60831201f2cce7f3b2e4846bf4d8728eabe54d60700b318a0b
     # via -r ci/requirements.in
+packaging==25.0 \
+    --hash=sha256:29572ef2b1f17581046b3a2227d5c611fb25ec70ca1ba8554b24b0e69331a484 \
+    --hash=sha256:d443872c98d677bf60f6a1f2f8c1cb748e8fe762d2bf9d3148b5599295b0fc4f
+    # via -r ci/requirements.in
 pycparser==2.22 \
     --hash=sha256:491c8be9c040f5390f5bf44a5b07752bd07f56edf992381b05c701439eec10f6 \
     --hash=sha256:c3702b6d3dd8c7abc1afa565d7e63d53a1d0bd86cdc24edd75470f4de499cfcc

docs/news.rst

@@ -50,6 +50,9 @@ Version History
   formally support free-threaded builds. (#276)
 * The C and Rust backends now declare the GIL as unused.
 * The `pythoncapi_compat.h` file has been upgraded to the latest version. (#278)
+* `setup.py` now depends on `packaging` and uses `packaging.version.Version` for
+  version comparisons. This removes some deprecation warnings from usage of
+  legacy distutils `Version` classes.
 
 0.24.0 (released 2025-08-17)
 ============================

setup.py

@@ -12,15 +12,9 @@
 import sys
 import sysconfig
 
+from packaging.version import Version
 from setuptools import setup
 
-# Python 3.12 dropped distutils from the stdlib. Try to access it via
-# setuptools.
-try:
-    from setuptools._distutils.version import LooseVersion
-except ImportError:
-    from distutils.version import LooseVersion
-
 if sys.version_info[0:2] < (3, 9):
     print("Python 3.9+ is required", file=sys.stderr)
     sys.exit(1)
@@ -61,8 +55,8 @@
 
     # PyPy (and possibly other distros) have CFFI distributed as part of
     # them.
-    cffi_version = LooseVersion(cffi.__version__)
-    if cffi_version < LooseVersion(MINIMUM_CFFI_VERSION):
+    cffi_version = Version(Version(cffi.__version__).base_version)
+    if cffi_version < Version(MINIMUM_CFFI_VERSION):
         print(
             "CFFI %s or newer required (%s found); "
             "not building CFFI backend" % (MINIMUM_CFFI_VERSION, cffi_version),