rust/hg-cpython/src/debug.rs

test-grep: document that trivially moved lines might not be detected

I'm not going to fix this. I just learned "grep --diff" does clever thing
than a simple grep(patch.diff(context=0)), and I think it's better to
document how things work.

// debug.rs
//
// Copyright 2020 Raphaël Gomès <[e-mail]>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

//! Module to get debug information about Rust extensions.
use cpython::{PyDict, PyModule, PyResult, Python};

/// Create the module, with `__package__` given from parent
pub fn init_module(py: Python, package: &str) -> PyResult<PyModule> {
    let dotted_name = &format!("{}.debug", package);
    let m = PyModule::new(py, dotted_name)?;

    m.add(py, "__package__", package)?;
    m.add(py, "__doc__", "Rust debugging information")?;

    let sys = PyModule::import(py, "sys")?;
    let sys_modules: PyDict = sys.get(py, "modules")?.extract(py)?;
    sys_modules.set_item(py, dotted_name, &m)?;

    Ok(m)
}