Segmentation fault when unwrapping a PyResult

[Alexander-N]

Calling .unwrap() on a PyResult causes a segfault.

🌍 Environment

• Your operating system and version: Ubuntu 18.10
• Your python version: 3.6.7
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?: apt
• Your rust version (rustc --version): rustc 1.38.0-nightly (83e4eed16 2019-07-14)
• Are you using the latest pyo3 version? Have you tried using latest master (replace version = "0.x.y" with git = "https://github.com/PyO3/pyo3")? yes

💥 Reproducing

use pyo3::PyResult;
use std::net::TcpListener;

fn connect() -> PyResult<bool> {
    TcpListener::bind("127.0.0.1:80")?;
    Ok(true)
}

fn main() {
    connect().unwrap();
}

[Alexander-N]

I guess some kind of initialization for the exception type is missing. The following panics as expected:

use pyo3::prelude::*;

fn fails() -> PyResult<(u32)> {
    Ok("not an integer".parse::<u32>()?)
}

fn main() {
    // Removing these lines causes a segfault
    let gil = Python::acquire_gil();
    let _py = gil.python();

    fails().unwrap();
}

[konstin]

Seems like PyErr is calling the ffi functions without acquiring the GIL first.