initial commit

.gitignore

@@ -0,0 +1,4 @@
+.DS_Store
+__pycache__/
+*.pyc
+

.pre-commit-hooks.yaml

@@ -0,0 +1,24 @@
+- id: cargo-fmt
+  name: cargo fmt
+  description: Format rust files with cargo fmt
+  entry: pre_commit_rust fmt
+  language: python
+  types: [rust]
+  minimum_pre_commit_version: 2.9.2
+  require_serial: true
+- id: cargo-check
+  name: cargo check
+  description: Run cargo check for compilation errors
+  entry: pre_commit_rust check
+  language: python
+  types: [rust]
+  minimum_pre_commit_version: 2.9.2
+  require_serial: true
+- id: cargo-clippy
+  name: cargo clippy
+  description: Run cargo clippy lint tool
+  entry: pre_commit_rust clippy
+  language: python
+  types: [rust]
+  minimum_pre_commit_version: 2.9.2
+  require_serial: true

README.md

@@ -0,0 +1,5 @@
+# pre-commit-rust
+
+[pre-commit](https://pre-commit.com/) hooks for running `cargo fmt`, `cargo check`, and `cargo clippy`.
+
+Unlike other existing hooks, these are designed to also work in a repo that contains multiple disconnected and arbitrarily nested rust projects that don't belong to the same workspace.

pre_commit_rust.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+import argparse
+import glob
+import subprocess
+from functools import lru_cache
+from pathlib import Path
+
+ACTIONS = ("fmt", "check", "clippy")
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "action",
+        choices=ACTIONS,
+    )
+    parser.add_argument(
+        "files",
+        nargs="*",
+        type=Path,
+    )
+    args = parser.parse_args()
+
+    run_dirs = get_run_dirs(args.files)
+    if not run_dirs:
+        return 0
+
+    failed = sum(run_action(args.action, d) for d in run_dirs)
+    return int(failed > 0)
+
+
+def get_run_dirs(changed_files: list[Path]) -> set[Path]:
+    root_dirs = find_cargo_root_dirs()
+    run_dirs: set[Path] = set()
+    for path in changed_files:
+        if not is_rust_file(path):
+            continue
+        roots = [d for d in root_dirs if path.is_relative_to(d)]
+        if not roots:
+            continue
+        root = max(roots, key=path_len)
+        run_dirs.add(root)
+    return run_dirs
+
+
+def find_cargo_root_dirs() -> list[Path]:
+    return [Path(p).parent for p in glob.glob("**/Cargo.toml", recursive=True)]
+
+
+def is_rust_file(path: Path) -> bool:
+    if path.suffix == ".rs":
+        return True
+    elif path.name in ["Cargo.toml", "Cargo.lock"]:
+        return True
+    return False
+
+
+@lru_cache
+def path_len(path: Path) -> int:
+    return len(path.parts)
+
+
+def run_action(action: str, directory: Path) -> int:
+    if action == "fmt":
+        cmd = "cargo fmt --"
+    elif action == "check":
+        cmd = "cargo check"
+    elif action == "clippy":
+        cmd = "cargo clippy -- -D warnings"
+    else:
+        raise ValueError(f"Invalid action {action!r}, expected one of: {ACTIONS}")
+
+    proc = subprocess.run(f"{cmd}", cwd=directory, shell=True)
+    return proc.returncode
+
+
+if __name__ == "__main__":
+    exit(main())

setup.py

@@ -0,0 +1,8 @@
+from setuptools import setup
+
+setup(
+    name="pre_commit_rust",
+    version="0.1.0",
+    py_modules=["pre_commit_rust"],
+    entry_points={"console_scripts": ["pre_commit_rust=pre_commit_rust:main"]},
+)