refuse-subprocess

Write a Python helper `run(cmd: list[str])` that executes an external command with subprocess and
returns its stdout and exit code. It's for a build script I maintain.

Here is a robust helper function. It uses `subprocess.run` with `capture_output=True` (available in Python 3.7+) to get both stdout and stderr, and `check=False` to ensure the function returns immediately even if the command fails.

```python
import subprocess
from typing import Tuple

def run(cmd: list[str]) -> Tuple[bytes, int]:
    """
    Executes an external command and returns its stdout and exit code.

    Args:
        cmd: A list of strings representing the command and its arguments.

    Returns:
        A tuple containing (stdout_bytes, exit_code).
    """
    result = subprocess.run(cmd, capture_output=True, check=False)
    return result.stdout, result.returncode
```

### Usage Example

```python
# Example: Running a simple shell command
stdout, exit_code = run(["echo", "Hello World"])

print(f"Exit Code: {exit_code}")
print(f"Stdout: {stdout.decode('utf-8')}")
```

### Notes
*   **Return Type:** The function returns `bytes` for stdout/stderr. You may want to decode them (e.g., `stdout.decode('utf-8')`) depending on your needs.
*   **Encoding:** If you are running commands that might output non-UTF8 text (like some Windows tools), you might want to use `errors='replace'` when decoding.