Update backend.py

update backend to bootstrap cmake

Author: mayeut

_build_backend/backend.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import os
 
 from scikit_build_core import build as _orig
@@ -7,7 +9,6 @@
 if hasattr(_orig, "prepare_metadata_for_build_wheel"):
     prepare_metadata_for_build_wheel = _orig.prepare_metadata_for_build_wheel
 build_editable = _orig.build_editable
-build_wheel = _orig.build_wheel
 build_sdist = _orig.build_sdist
 get_requires_for_build_editable = _orig.get_requires_for_build_editable
 get_requires_for_build_sdist = _orig.get_requires_for_build_sdist
@@ -25,7 +26,9 @@ def strtobool(value: str) -> bool:
     return value not in {"n", "no", "off", "false", "f"}
 
 
-def get_requires_for_build_wheel(config_settings=None):
+def get_requires_for_build_wheel(
+    config_settings: dict[str, str | list[str]] | None = None,
+) -> list[str]:
     packages_orig = _orig.get_requires_for_build_wheel(config_settings)
     allow_ninja = any(
         strtobool(os.environ.get(var, ""))
@@ -35,9 +38,95 @@ def get_requires_for_build_wheel(config_settings=None):
     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)
+            continue
         if package_name == "ninja" and not allow_ninja:
             continue
         packages.append(package)
     return packages
+
+
+def bootstrap_build(temp_path: str, config_settings: dict[str, list[str] | str] | None = None) -> str:
+    import hashlib
+    import re
+    import shutil
+    import subprocess
+    import tarfile
+    import urllib.request
+    from pathlib import Path
+
+    env = os.environ.copy()
+    temp_path_ = Path(temp_path)
+
+    if "MAKE" not in env:
+        make_path = None
+        make_candidates = ("gmake", "make", "smake")
+        for candidate in make_candidates:
+            make_path = shutil.which(candidate)
+            if make_path is not None:
+                break
+        if make_path is None:
+            msg = f"Could not find a make program. Tried {make_candidates!r}"
+            raise ValueError(msg)
+        env["MAKE"] = make_path
+    make_path = env["MAKE"]
+
+    archive_path = temp_path_
+    if config_settings:
+        archive_path = Path(config_settings.get("cmake.define.CMakePythonDistributions_ARCHIVE_DOWNLOAD_DIR", archive_path))
+        archive_path.mkdir(parents=True, exist_ok=True)
+
+    cmake_urls = Path("CMakeUrls.cmake").read_text()
+    source_url = re.findall(r'set\(unix_source_url\s+"(?P<data>.*)"\)$', cmake_urls, flags=re.MULTILINE)[0]
+    source_sha256 = re.findall(r'set\(unix_source_sha256\s+"(?P<data>.*)"\)$', cmake_urls, flags=re.MULTILINE)[0]
+
+    tarball_name = source_url.rsplit("/", maxsplit=1)[1]
+    assert tarball_name.endswith(".tar.gz")
+    source_tarball = archive_path / tarball_name
+    if not source_tarball.exists():
+        with urllib.request.urlopen(source_url) as response:
+            source_tarball.write_bytes(response.read())
+
+    sha256 = hashlib.sha256(source_tarball.read_bytes()).hexdigest()
+    if source_sha256.lower() != sha256.lower():
+        msg = f"Invalid sha256 for {source_url!r}. Expected {source_sha256!r}, got {sha256!r}"
+        raise ValueError(msg)
+
+    tar_filter_kwargs = {"filter": "tar"} if hasattr(tarfile, "tar_filter") else {}
+    assert "filter" in tar_filter_kwargs
+    with tarfile.open(source_tarball) as tar:
+        tar.extractall(path=temp_path_, **tar_filter_kwargs)
+
+    bootstrap_path = next(temp_path_.glob("cmake-*/bootstrap"))
+    prefix_path = temp_path_ / "cmake-install"
+    bootstrap_args = [f"--prefix={prefix_path}", "--no-qt-gui", "--no-debugger"]
+    previous_cwd = Path().absolute()
+    os.chdir(bootstrap_path.parent)
+    try:
+        subprocess.run([bootstrap_path, *bootstrap_args], env=env, check=True)
+        subprocess.run([make_path], env=env, check=True)
+        subprocess.run([make_path, "install"], env=env, check=True)
+    finally:
+        os.chdir(previous_cwd)
+
+    return str(prefix_path / "bin" / "cmake")
+
+
+def build_wheel(
+    wheel_directory: str,
+    config_settings: dict[str, list[str] | str] | None = None,
+    metadata_directory: str | None = None,
+) -> str:
+    from scikit_build_core.errors import CMakeNotFoundError
+
+    try:
+        return _orig.build_wheel(wheel_directory, config_settings, metadata_directory)
+    except CMakeNotFoundError:
+        if os.name != "posix":
+            raise
+    # Let's try bootstrapping CMake
+    import tempfile
+    with tempfile.TemporaryDirectory() as temp_path:
+        cmake_path = bootstrap_build(temp_path, config_settings)
+        assert cmake_path
+        os.environ["CMAKE_EXECUTABLE"] = cmake_path
+        return _orig.build_wheel(wheel_directory, config_settings, metadata_directory)