build/rust/gni_impl/clippy_wrapper.py

#!/usr/bin/env python3

# Copyright 2026 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import argparse
import subprocess
import pathlib
import sys
import tempfile

from rustc_wrapper import (ConvertPathsToAbsolute, LoadRustEnvAndFlags,
                           HandleReturnCode)


def main():
  parser = argparse.ArgumentParser()
  parser.add_argument('--clippy-driver', required=True, type=pathlib.Path)
  parser.add_argument('--rustc-env-and-flags', type=pathlib.Path, required=True)
  parser.add_argument('--build-stamp-file', type=pathlib.Path, required=True)
  args = parser.parse_args()

  (rustenv, rustflags) = LoadRustEnvAndFlags(args.rustc_env_and_flags)
  ConvertPathsToAbsolute(rustenv)

  # `clippy-driver` should not write any files into the build directory
  # (e.g. into `out/`).
  #
  # `--emit=metadata` asks Clippy to only emit `.rmeta`.  This:
  # * Matches how `cargo clippy` invokes `clippy-driver` - see
  #   https://crrev.com/c/7316228/17#message-fa234861e30ee37399388ca5a6a048822b658833
  # * Seems sufficient for triggering Clippy lints.
  # * Avoids performance overhead (and general ickiness) of also building
  #   `.rlib` from within `clippy-driver`.
  assert not [x for x in rustflags if x.startswith("--emit")]
  assert not [x for x in rustflags if x.startswith("-o")]
  assert not [x for x in rustflags if x.startswith("--out-dir")]
  temp_dir = tempfile.TemporaryDirectory()
  rustflags += ["--out-dir", temp_dir.name]
  rustflags += ["--emit=metadata"]

  r = subprocess.run([args.clippy_driver, *rustflags], env=rustenv, check=False)
  if r.returncode != 0:
    print("NOTE: See `//docs/rust/clippy.md` for more Clippy info.",
          file=sys.stderr)
    HandleReturnCode(r, args.rustc_env_and_flags)
    assert False  # `HandleReturnCode` should call `sys.exit` for non-0 code.

  args.build_stamp_file.touch()
  return 0


if __name__ == '__main__':
  sys.exit(main())