BLD: avoid a deprecation warning from setuptools (PEP 735 license metadata)

Author: neutrinoceros

MANIFEST.in

@@ -27,4 +27,3 @@ include *.md
 include *.py
 include *.release
 include *.sh
-include LICENSE

pyproject.toml

@@ -3,7 +3,8 @@ requires = [
     "Cython>=0.29",
     "oldest-supported-numpy ; python_version < '3.9'",
     "numpy>=2.0.0rc1 ; python_version >= '3.9'",
-    "setuptools>=61", "setuptools_scm[toml]>=3.4"
+    "setuptools>=77.0.1",
+    "setuptools_scm[toml]>=3.4",
 ]
 build-backend = "setuptools.build_meta"
 
@@ -18,7 +19,8 @@ keywords = [
     "numpy", "netcdf", "data", "science", "network", "oceanography",
     "meteorology", "climate",
 ]
-license = {text = "MIT"}
+license = "MIT"
+license-files = ["LICENSE"]
 classifiers = [
     "Development Status :: 3 - Alpha",
     "Programming Language :: Python :: 3",
@@ -28,7 +30,6 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Intended Audience :: Science/Research",
-    "License :: OSI Approved :: MIT License",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: System :: Archiving :: Compression",
     "Operating System :: OS Independent",

setup.py

@@ -3,11 +3,27 @@
 import pathlib
 import shutil
 import configparser
+import sysconfig
 from setuptools import setup, Extension
 from setuptools.dist import Distribution
 from typing import List
 
 
+USE_PY_LIMITED_API = (
+    # require opt-in (builds are specilized by default)
+    os.getenv('NETCDF4_LIMITED_API', '0') == '1'
+    # Cython + numpy + limited API de facto requires Python >=3.11
+    and sys.version_info >= (3, 11) 
+    # as of Python 3.14t, free-threaded builds don't support the limited API
+    and not sysconfig.get_config_var("Py_GIL_DISABLED")
+)
+ABI3_TARGET_VERSION = "".join(str(_) for _ in sys.version_info[:2])
+ABI3_TARGET_HEX = hex(sys.hexversion & 0xFFFF00F0)
+
+if USE_PY_LIMITED_API:
+    SETUP_OPTIONS = {"bdist_wheel": {"py_limited_api", f"cp{ABI3_TARGET_VERSION}"}}
+else:
+    SETUP_OPTIONS = {}
 
 open_kwargs = {'encoding': 'utf-8'}
 
@@ -436,6 +452,8 @@ def _populate_hdf5_info(dirstosearch, inc_dirs, libs, lib_dirs):
         str(nc_complex_dir / "include/generated_fallbacks"),
     ]
     DEFINE_MACROS += [("NC_COMPLEX_NO_EXPORT", "1")]
+    if USE_PY_LIMITED_API:
+        DEFINE_MACROS.append(("Py_LIMITED_API", ABI3_TARGET_HEX))
 
     ext_modules = [Extension("netCDF4._netCDF4",
                              source_files,
@@ -477,6 +495,7 @@ def _populate_hdf5_info(dirstosearch, inc_dirs, libs, lib_dirs):
     name="netCDF4",  # need by GitHub dependency graph
     version=extract_version(netcdf4_src_pyx),
     ext_modules=ext_modules,
+    options=SETUP_OPTIONS,
 )
 
 # remove plugin files copied from outside source tree