feature: allow local runs on windows/macOS (#974)

* feature: allow local runs on windows/macOS

Cache python installations to a user cache folder using platformdirs.
The build environment is now a virtual environment to allow proper isolation.
Allows to run tests in parallel.

Co-authored-by: Joe Rickerby <joerick@mac.com>

bin/update_virtualenv.py

@@ -0,0 +1,120 @@
+#!/usr/bin/env python3
+
+from __future__ import annotations
+
+import difflib
+import logging
+import subprocess
+from pathlib import Path
+from typing import NamedTuple
+
+import click
+import rich
+import tomli
+from packaging.version import InvalidVersion, Version
+from rich.logging import RichHandler
+from rich.syntax import Syntax
+
+from cibuildwheel.typing import Final
+
+log = logging.getLogger("cibw")
+
+# Looking up the dir instead of using utils.resources_dir
+# since we want to write to it.
+DIR: Final[Path] = Path(__file__).parent.parent.resolve()
+RESOURCES_DIR: Final[Path] = DIR / "cibuildwheel/resources"
+
+GET_VIRTUALENV_GITHUB: Final[str] = "https://github.com/pypa/get-virtualenv"
+GET_VIRTUALENV_URL_TEMPLATE: Final[
+    str
+] = f"{GET_VIRTUALENV_GITHUB}/blob/{{version}}/public/virtualenv.pyz?raw=true"
+
+
+class VersionTuple(NamedTuple):
+    version: Version
+    version_string: str
+
+
+def git_ls_remote_versions(url) -> list[VersionTuple]:
+    versions: list[VersionTuple] = []
+    tags = subprocess.run(
+        ["git", "ls-remote", "--tags", url], check=True, text=True, capture_output=True
+    ).stdout.splitlines()
+    for tag in tags:
+        _, ref = tag.split()
+        assert ref.startswith("refs/tags/")
+        version_string = ref[10:]
+        try:
+            version = Version(version_string)
+            if version.is_devrelease:
+                log.info(f"Ignoring development release '{version}'")
+                continue
+            if version.is_prerelease:
+                log.info(f"Ignoring pre-release '{version}'")
+                continue
+            versions.append(VersionTuple(version, version_string))
+        except InvalidVersion:
+            log.warning(f"Ignoring ref '{ref}'")
+    versions.sort(reverse=True)
+    return versions
+
+
+@click.command()
+@click.option("--force", is_flag=True)
+@click.option(
+    "--level", default="INFO", type=click.Choice(["WARNING", "INFO", "DEBUG"], case_sensitive=False)
+)
+def update_virtualenv(force: bool, level: str) -> None:
+
+    logging.basicConfig(
+        level="INFO",
+        format="%(message)s",
+        datefmt="[%X]",
+        handlers=[RichHandler(rich_tracebacks=True, markup=True)],
+    )
+    log.setLevel(level)
+
+    toml_file_path = RESOURCES_DIR / "virtualenv.toml"
+
+    original_toml = toml_file_path.read_text()
+    with toml_file_path.open("rb") as f:
+        loaded_file = tomli.load(f)
+    version = str(loaded_file["version"])
+    versions = git_ls_remote_versions(GET_VIRTUALENV_GITHUB)
+    if versions[0].version > Version(version):
+        version = versions[0].version_string
+
+    result_toml = (
+        f'version = "{version}"\n'
+        f'url = "{GET_VIRTUALENV_URL_TEMPLATE.format(version=version)}"\n'
+    )
+
+    rich.print()  # spacer
+
+    if original_toml == result_toml:
+        rich.print("[green]Check complete, virtualenv version unchanged.")
+        return
+
+    rich.print("virtualenv version updated.")
+    rich.print("Changes:")
+    rich.print()
+
+    toml_relpath = toml_file_path.relative_to(DIR).as_posix()
+    diff_lines = difflib.unified_diff(
+        original_toml.splitlines(keepends=True),
+        result_toml.splitlines(keepends=True),
+        fromfile=toml_relpath,
+        tofile=toml_relpath,
+    )
+    rich.print(Syntax("".join(diff_lines), "diff", theme="ansi_light"))
+    rich.print()
+
+    if force:
+        toml_file_path.write_text(result_toml)
+        rich.print("[green]TOML file updated.")
+    else:
+        rich.print("[yellow]File left unchanged. Use --force flag to update.")
+
+
+if __name__ == "__main__":
+    update_virtualenv()