From fbf6e63a3e1fc055d56682de89c30b35b4107c40 Mon Sep 17 00:00:00 2001
From: Jason Barnett <862300+jasonwbarnett@users.noreply.github.com>
Date: Wed, 15 Jul 2026 19:45:49 +0000
Subject: [PATCH] Replace deprecated pkg_resources with packaging in setup.py

setup.py used pkg_resources.Requirement to validate the installed Cython
version at build time. pkg_resources is deprecated by setuptools and slated
for removal: it emits a DeprecationWarning on import and is unavailable in
some modern setuptools configurations, which can make source builds warn or
fail.

Port the check to the packaging library:
  - pkg_resources.Requirement.parse(CYTHON_DEPENDENCY)
      -> packaging.requirements.Requirement(CYTHON_DEPENDENCY)
  - Cython.__version__ not in cython_dep
      -> not cython_dep.specifier.contains(Cython.__version__, prereleases=True)

pkg_resources.Requirement.__contains__ passed prereleases=True internally, so
passing prereleases=True preserves the original behavior exactly. Add
packaging>=20 to build-system.requires so it is available when building from
source.

Mirrors the same fix in the sister project MagicStack/uvloop@b377b7c.

Refs: MagicStack/asyncpg#1337

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ScLtrCvUAVqPrVbcqsGUDJ
---
 pyproject.toml | 3 ++-
 setup.py       | 8 +++++---
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index e2b18388..5d09895b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -62,7 +62,8 @@ docs = [
 [build-system]
 requires = [
     "setuptools>=77.0.3",
-    "Cython(>=3.2.1,<4.0.0)"
+    "Cython(>=3.2.1,<4.0.0)",
+    "packaging>=20"
 ]
 build-backend = "setuptools.build_meta"
 
diff --git a/setup.py b/setup.py
index f9fafadf..5fdc53ff 100644
--- a/setup.py
+++ b/setup.py
@@ -188,7 +188,7 @@ def finalize_options(self):
                         need_cythonize = True
 
         if need_cythonize:
-            import pkg_resources
+            from packaging.requirements import Requirement
 
             # Double check Cython presence in case setup_requires
             # didn't go into effect (most likely because someone
@@ -201,8 +201,10 @@ def finalize_options(self):
                     'please install {} to compile asyncpg from source'.format(
                         CYTHON_DEPENDENCY))
 
-            cython_dep = pkg_resources.Requirement.parse(CYTHON_DEPENDENCY)
-            if Cython.__version__ not in cython_dep:
+            cython_dep = Requirement(CYTHON_DEPENDENCY)
+            if not cython_dep.specifier.contains(
+                Cython.__version__, prereleases=True
+            ):
                 raise RuntimeError(
                     'asyncpg requires {}, got Cython=={}'.format(
                         CYTHON_DEPENDENCY, Cython.__version__