add pre-commit hazmat

pre_commit/commands/hazmat.py

@@ -0,0 +1,95 @@
+from __future__ import annotations
+
+import argparse
+import subprocess
+from collections.abc import Sequence
+
+from pre_commit.parse_shebang import normalize_cmd
+
+
+def add_parsers(parser: argparse.ArgumentParser) -> None:
+    subparsers = parser.add_subparsers(dest='tool')
+
+    cd_parser = subparsers.add_parser(
+        'cd', help='cd to a subdir and run the command',
+    )
+    cd_parser.add_argument('subdir')
+    cd_parser.add_argument('cmd', nargs=argparse.REMAINDER)
+
+    ignore_exit_code_parser = subparsers.add_parser(
+        'ignore-exit-code', help='run the command but ignore the exit code',
+    )
+    ignore_exit_code_parser.add_argument('cmd', nargs=argparse.REMAINDER)
+
+    n1_parser = subparsers.add_parser(
+        'n1', help='run the command once per filename',
+    )
+    n1_parser.add_argument('cmd', nargs=argparse.REMAINDER)
+
+
+def _cmd_filenames(cmd: tuple[str, ...]) -> tuple[
+    tuple[str, ...],
+    tuple[str, ...],
+]:
+    for idx, val in enumerate(reversed(cmd)):
+        if val == '--':
+            split = len(cmd) - idx
+            break
+    else:
+        raise SystemExit('hazmat entry must end with `--`')
+
+    return cmd[:split - 1], cmd[split:]
+
+
+def cd(subdir: str, cmd: tuple[str, ...]) -> int:
+    cmd, filenames = _cmd_filenames(cmd)
+
+    prefix = f'{subdir}/'
+    new_filenames = []
+    for filename in filenames:
+        if not filename.startswith(prefix):
+            raise SystemExit(f'unexpected file without {prefix=}: {filename}')
+        else:
+            new_filenames.append(filename.removeprefix(prefix))
+
+    cmd = normalize_cmd(cmd)
+    return subprocess.call((*cmd, *new_filenames), cwd=subdir)
+
+
+def ignore_exit_code(cmd: tuple[str, ...]) -> int:
+    cmd = normalize_cmd(cmd)
+    subprocess.call(cmd)
+    return 0
+
+
+def n1(cmd: tuple[str, ...]) -> int:
+    cmd, filenames = _cmd_filenames(cmd)
+    cmd = normalize_cmd(cmd)
+    ret = 0
+    for filename in filenames:
+        ret |= subprocess.call((*cmd, filename))
+    return ret
+
+
+def impl(args: argparse.Namespace) -> int:
+    args.cmd = tuple(args.cmd)
+    if args.tool == 'cd':
+        return cd(args.subdir, args.cmd)
+    elif args.tool == 'ignore-exit-code':
+        return ignore_exit_code(args.cmd)
+    elif args.tool == 'n1':
+        return n1(args.cmd)
+    else:
+        raise NotImplementedError(f'unexpected tool: {args.tool}')
+
+
+def main(argv: Sequence[str] | None = None) -> int:
+    parser = argparse.ArgumentParser()
+    add_parsers(parser)
+    args = parser.parse_args(argv)
+
+    return impl(args)
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())