use a custom build backend

Author: mayeut

_build_backend/backend.py

@@ -0,0 +1,19 @@
+from scikit_build_core import build as _orig
+
+prepare_metadata_for_build_wheel = _orig.prepare_metadata_for_build_wheel
+build_wheel = _orig.build_wheel
+build_sdist = _orig.build_sdist
+get_requires_for_build_sdist = _orig.get_requires_for_build_sdist
+
+def get_requires_for_build_wheel(config_settings=None):
+    packages_orig = _orig.get_requires_for_build_wheel(config_settings)
+    packages = []
+    for package in packages_orig:
+        package_name = package.lower().split(">")[0].strip()
+        if package_name == "cmake":
+            msg = f"CMake PyPI distibution requires {package} to be available on the build system"
+            raise ValueError(msg)
+        if package_name == "ninja":
+            continue
+        packages.append(package)
+    return packages

pyproject.toml

@@ -1,6 +1,7 @@
 [build-system]
-requires = ["scikit-build-core"]
-build-backend = "scikit_build_core.build"
+requires = ["scikit-build-core>=0.10"]
+build-backend = "backend"
+backend-path = ["_build_backend"]
 
 [project]
 name = "cmake"
@@ -51,9 +52,9 @@ cpack = "cmake:cpack"
 ctest = "cmake:ctest"
 
 [tool.scikit-build]
-minimum-version = "0.8"
+minimum-version = "build-system.requires"
 build-dir = "build/{wheel_tag}"
-cmake.version = ""  # We are cmake, so don't request cmake
+cmake.version = ">=3.15"
 ninja.version = ""  # requiring ninja could cause it to request CMake if it needs to be built from sources, fallback to make
 ninja.make-fallback = true
 wheel.py-api = "py3"