Implementing __setattr__ errors

[danieldk]

🐛 Bug Reports

When reporting a bug, please provide the following information. If this is not a bug report you can just discard this template.

🌍 Environment

• Your operating system and version: NixOS 19.09
• Your python version: 3.7
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?: nix-shell
• Your rust version (rustc --version): rustc 1.38.0-nightly (311376d30 2019-07-18)
• Are you using the latest pyo3 version? No

💥 Reproducing

#[pyclass(name=Test)]
pub struct PyTest {
    foo: usize,
}

#[pyproto]
impl PyObjectProtocol for PyTest {
    fn __setattr__(&mut self, name: String, value: String) -> PyResult<()> {
        Ok(())
    }
}

Fails with:

error[E0437]: type `Success` is not a member of trait `pyo3::class::basic::PyObjectSetAttrProtocol`
   --> src/sentence.rs:251:1
    |
251 | #[pyproto]
    | ^^^^^^^^^^ not a member of trait `pyo3::class::basic::PyObjectSetAttrProtocol`

error: aborting due to previous error

__getattr__ works fine on the other hand.

[sebpuetz]

Should be fixed by #645, in the meantime it's possible to replace the code generated by the proc-macro with the correct impls:

use pyo3::{PyObjectProtocol, PyResult};
use pyo3::prelude::*;
use pyo3::class::basic::PyObjectSetAttrProtocol;

#[pyclass(name=Test)]
pub struct PyTest {
    foo: usize,
}

impl<'p> PyObjectProtocol<'p> for PyTest {
    fn __setattr__(
        &'p mut self,
        name: <PyTest as PyObjectSetAttrProtocol<'p>>::Name,
        value: <PyTest as PyObjectSetAttrProtocol<'p>>::Value,
    ) -> <PyTest as PyObjectSetAttrProtocol<'p>>::Result {
        Ok(())
    }
}
impl<'p> PyObjectSetAttrProtocol<'p> for PyTest {
    type Name = String;
    type Value = String;
    type Result = PyResult<()>;
}