Scans a Rust project directory and assigns unique sequential numbers to any un-numbered `// TODO` comments in-place (e.g. `// TODO` → `// TODO(42)`).

number_todos.py

#!/usr/bin/env python3
"""Number unnumbered // TODO comments across Rust files."""

import re
import sys
from pathlib import Path


# Matches "// TODO" NOT followed by "(number)"
UNNUMBERED_TODO = re.compile(r"// TODO(?!\(\d+\))")


def find_rust_files(directory: Path):
    return sorted(directory.rglob("*.rs"))


def number_todos(directory: Path):
    rust_files = find_rust_files(directory)
    counter = 0

    for path in rust_files:
        text = path.read_text()
        new_lines = []
        changed = False

        for line in text.splitlines(keepends=True):
            if UNNUMBERED_TODO.search(line):
                counter += 1
                line = UNNUMBERED_TODO.sub(f"// TODO({counter})", line, count=1)
                changed = True
            new_lines.append(line)

        if changed:
            path.write_text("".join(new_lines))
            print(f"Updated: {path}")

    print(f"\nNumbered {counter} TODO(s) across {len(rust_files)} file(s).")


if __name__ == "__main__":
    target = Path(sys.argv[1]) if len(sys.argv) > 1 else Path(".")
    if not target.is_dir():
        print(f"Error: {target} is not a directory", file=sys.stderr)
        sys.exit(1)
    number_todos(target)