kwargs isn't working.

[rodyzi]

https://stackoverflow.com/questions/54015328/calling-from-python-rust-function-with-kwargs-fails

🌍 Environment

• Your operating system and version: Arch Linux 4.19.12
• Your python version: 3.7.1
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?: system package manager - pacman
• Your rust version (rustc --version): 1.33.0-nightly 2018-12-22
• Are you using the latest pyo3 version? Have you tried using latest master? yes

💥 Reproducing

#![feature(custom_attribute)]
#![feature(specialization)]

use pyo3::prelude::*;
use pyo3::types::{PyDict, PyTuple};

#[pyclass]
struct MyClass {}

#[pymethods]
impl MyClass {
    #[staticmethod]
    #[args(kwargs = "**")]
    fn test1(kwargs: Option<&PyDict>) -> PyResult<()> {
        if let Some(kwargs) = kwargs {
            for kwarg in kwargs {
                println!("{:?}", kwarg);
            }
        } else {
            println!("kwargs is none");
        }
        Ok(())
    }

    #[staticmethod]
    #[args(args = "*")]
    fn test2(args: &PyTuple) -> PyResult<()> {
        for arg in args {
            println!("{:?}", arg);
        }
        Ok(())
    }
}


#[pymodule]
fn test123(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_class::<MyClass>()?;
    Ok(())
}

Install using pyo3-pack.

pyo3-pack build --interpreter python3.7
cd target/wheels
sudo pip install --force-reinstall test123-0.1.0-cp37-cp37m-manylinux1_x86_64.whl

import test123
test123.MyClass.test1(test=1) // fails with `MyClass.test1()() takes at most 0 argument (1 given)`
test123.MyClass.test2(1) // success