feat: support vendoring with command (#32)

Signed-off-by: Henry Schreiner <[email protected]>

.pre-commit-config.yaml

@@ -56,6 +56,7 @@ repos:
         additional_dependencies:
           - pytest
           - scikit-build-core
+          - importlib-resources
 
   - repo: https://github.com/codespell-project/codespell
     rev: "v2.3.0"

README.md

@@ -15,6 +15,31 @@
 
 <!-- SPHINX-START -->
 
+## Vendoring
+
+You can vendor FindCython and/or UseCython into your package, as well. This
+avoids requiring a dependency at build time and protects you against changes in
+this package, at the expense of requiring manual re-vendoring to get bugfixes
+and/or improvements. This mechanism is also ideal if you want to support direct
+builds, outside of scikit-build-core.
+
+You should make a CMake helper directory, such as `cmake`. Add this to your
+`CMakeLists.txt` like this:
+
+```cmake
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
+```
+
+Then, you can vendor our files into that folder:
+
+```bash
+pipx run cython-cmake vendor cmake
+```
+
+If you want to just vendor one of the two files, use `--member FindCython` or
+`--member UseCython`. You can rerun this command to revendor. The directory must
+already exist.
+
 <!-- prettier-ignore-start -->
 [actions-badge]:            https://github.com/scikit-build/cython-cmake/workflows/CI/badge.svg
 [actions-link]:             https://github.com/scikit-build/cython-cmake/actions

pyproject.toml

@@ -30,11 +30,16 @@ classifiers = [
   "Typing :: Typed",
 ]
 dynamic = ["version"]
-dependencies = []
+dependencies = [
+  "importlib_resources; python_version<'3.9'"
+]
 
 [project.entry-points."cmake.module"]
 any = "cython_cmake.cmake"
 
+[project.scripts]
+cython-cmake = "cython_cmake.__main__:main"
+
 [project.optional-dependencies]
 test = [
   "pytest >=6",
@@ -152,7 +157,9 @@ similarities.ignore-imports = "yes"
 messages_control.disable = [
   "design",
   "fixme",
+  "invalid-name",
   "line-too-long",
+  "missing-class-docstring",
   "missing-module-docstring",
   "wrong-import-position",
 ]

src/cython_cmake/__main__.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+
+import argparse
+import enum
+import functools
+import operator
+from collections.abc import Sequence
+from pathlib import Path
+from typing import Any
+
+from ._version import version as __version__
+from .vendor import Members, vendorize
+
+__all__ = ["main"]
+
+
+def __dir__() -> list[str]:
+    return __all__
+
+
+class FlagAction(argparse.Action):
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        enum_type = kwargs.pop("type", None)
+        if enum_type is None:
+            msg = "enum type is required"
+            raise ValueError(msg)
+        if not issubclass(enum_type, enum.Flag):
+            msg = "type must be an Flag when using FlagAction"
+            raise TypeError(msg)
+
+        kwargs.setdefault("choices", tuple(e.name for e in enum_type))
+
+        super().__init__(*args, **kwargs)
+
+        self._enum = enum_type
+
+    def __call__(
+        self,
+        parser: argparse.ArgumentParser,  # noqa: ARG002
+        namespace: argparse.Namespace,
+        values: str | Sequence[Any] | None,
+        option_string: str | None = None,  # noqa: ARG002
+    ) -> None:
+        if not isinstance(values, list):
+            values = [values]
+        flags = functools.reduce(operator.or_, (self._enum[e] for e in values))
+        setattr(namespace, self.dest, flags)
+
+
+def main() -> None:
+    """
+    Entry point.
+    """
+    parser = argparse.ArgumentParser(
+        prog="cython_cmake", description="CMake Cython module helper"
+    )
+    parser.add_argument(
+        "--version", action="version", version=f"%(prog)s {__version__}"
+    )
+    subparser = parser.add_subparsers(required=True)
+    vendor_parser = subparser.add_parser("vendor", help="Vendor CMake helpers")
+    vendor_parser.add_argument(
+        "target", type=Path, help="Directory to vendor the CMake helpers"
+    )
+    vendor_parser.add_argument(
+        "--members",
+        type=Members,
+        nargs="*",
+        action=FlagAction,
+        default=functools.reduce(operator.or_, list(Members)),
+        help="Members to vendor, defaults to all",
+    )
+    args = parser.parse_args()
+    vendorize(args.target, args.members)
+
+
+if __name__ == "__main__":
+    main()

src/cython_cmake/vendor.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+import enum
+import sys
+from pathlib import Path
+
+if sys.version_info < (3, 9):
+    from importlib_resources import files
+else:
+    from importlib.resources import files
+
+__all__ = ["vendorize", "Members"]
+
+
+def __dir__() -> list[str]:
+    return __all__
+
+
+class Members(enum.Flag):
+    FindCython = enum.auto()
+    UseCython = enum.auto()
+
+
+def vendorize(
+    target: Path, members: Members = Members.FindCython | Members.UseCython
+) -> None:
+    """
+    Vendorize files into a directory. Directory must exist.
+    """
+    if not target.is_dir():
+        msg = f"Target directory {target} does not exist"
+        raise AssertionError(msg)
+
+    cmake_dir = files("cython_cmake") / "cmake"
+    if Members.FindCython in members:
+        find = cmake_dir / "FindCython.cmake"
+        find_target = target / "FindCython.cmake"
+        find_target.write_text(find.read_text(encoding="utf-8"), encoding="utf-8")
+
+    if Members.UseCython in members:
+        use = cmake_dir / "UseCython.cmake"
+        use_target = target / "UseCython.cmake"
+        use_target.write_text(use.read_text(encoding="utf-8"), encoding="utf-8")

tests/test_vendorize.py

@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+import pytest
+
+from cython_cmake.__main__ import main
+
+DIR = Path(__file__).parent.resolve()
+FIND_CYTHON = DIR.parent.joinpath("src/cython_cmake/cmake/FindCython.cmake").read_text()
+USE_CYTHON = DIR.parent.joinpath("src/cython_cmake/cmake/UseCython.cmake").read_text()
+
+
+def test_copy_files(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    path = tmp_path / "copy_all"
+    path.mkdir()
+
+    monkeypatch.setattr(sys, "argv", [sys.executable, "vendor", str(path)])
+    main()
+
+    assert path.joinpath("FindCython.cmake").read_text() == FIND_CYTHON
+    assert path.joinpath("UseCython.cmake").read_text() == USE_CYTHON
+
+
+def test_copy_only_find(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    path = tmp_path / "copy_find"
+    path.mkdir()
+
+    monkeypatch.setattr(
+        sys, "argv", [sys.executable, "vendor", str(path), "--member", "FindCython"]
+    )
+    main()
+
+    assert path.joinpath("FindCython.cmake").read_text() == FIND_CYTHON
+    assert not path.joinpath("UseCython.cmake").exists()