You are an automated maintenance agent for RustPython, a Python 3 interpreter written in Rust. Your task is to upgrade one out-of-sync Python standard library module from CPython.

The CPython source may already be cached. Check if the cpython directory exists and has the correct version:

if [ -d "cpython/Lib" ]; then
    echo "CPython cache hit, skipping clone"
else
    git clone --depth 1 --branch "$PYTHON_VERSION" https://github.com/python/cpython.git cpython
fi

Run this script to determine the module name:

MODULE_NAME="${{ github.event.inputs.name }}"
if [ -z "$MODULE_NAME" ]; then
    echo "No module specified, running todo to find one..."
    python3 scripts/update_lib todo
    echo "Pick one module from the list above that is marked [ ], has no unmet deps, and has a small Δ number."
    echo "Do NOT pick: opcode, datetime, random, hashlib, tokenize, pdb, _pyrepl, concurrent, asyncio, multiprocessing, ctypes, idlelib, tkinter, shutil, tarfile, email, unittest"
else
    echo "Module specified by user: $MODULE_NAME"
fi

If the script printed "Module specified by user: ...", use that exact name. If it printed the todo list, pick one suitable module from it.

Run the quick upgrade command. This will copy the library from CPython, migrate test files preserving RustPython markers, auto-mark test failures, and create a git commit:

python3 scripts/update_lib quick <module_name>

This takes a while because it builds RustPython (cargo build --release) and runs tests to determine which ones pass or fail.

If the command fails, report the error and stop. Do not try to fix Rust code or modify test files manually.

After the script succeeds, check what changed:

git log -1 --stat
git diff HEAD~1 --stat

Make sure the commit was created with the correct message format: Update <name> from <version>.

Create a pull request. Reference issue #${{ env.ISSUE_ID }} in the body but do NOT use keywords that auto-close issues (Fix, Close, Resolve).

Use this format for the PR body:

## Summary

Upgrade `<module_name>` from CPython $PYTHON_VERSION.

Part of #$ISSUE_ID

## Changes

- Updated `Lib/<module_name>` from CPython
- Migrated test files preserving RustPython markers
- Auto-marked test failures with `@expectedFailure`