Automatically call CMake as part of PEP 517 build

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
-requires = ["setuptools >= 63.0.0"]
-build-backend = "setuptools.build_meta"
+requires = ["scikit-build-core", "setuptools >= 63.0.0"]
+build-backend = "scikit_build_core.setuptools.build_meta"
 
 [project]
 name = "bitsandbytes"

setup.py

@@ -2,7 +2,11 @@
 #
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
+from distutils.errors import DistutilsModuleError
+from warnings import warn
+
 from setuptools import find_packages, setup
+from setuptools.command.build_py import build_py
 from setuptools.dist import Distribution
 
 
@@ -12,4 +16,22 @@ def has_ext_modules(self):
         return True
 
 
-setup(version="0.45.3.dev0", packages=find_packages(), distclass=BinaryDistribution)
+class ExtBuildPy(build_py):
+    def run(self):
+        # build_cmake needs to be called prior to build_py, as the latter
+        # collects the files output into the package directory.
+        try:
+            self.run_command("build_cmake")
+        except DistutilsModuleError:
+            warn("scikit-build-core not installed, CMake will not be invoked automatically. "
+                 "Please install scikit-build-core or run CMake manually to build extensions.")
+        super().run()
+
+
+setup(version="0.45.3.dev0",
+      packages=find_packages(),
+      distclass=BinaryDistribution,
+      cmake_source_dir=".",
+      cmdclass={
+          "build_py": ExtBuildPy,
+      })