prepare_freethreaded_python in crate pyo3 on OSX Big Sur

[sansyrox]

🐛 Bug Reports

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

I am getting the error : prepare_freethreaded_python in crate pyo3 on OSX Big Sur when I am using the prepare_freethreaded_python function.

🌍 Environment

• Your operating system and version: OSX Big Sur
• Your python version: 3.9
• How did you install python (e.g. apt or pyenv)? Did you use a virtualenv?:
• Your Rust version (rustc --version): 1.50.0 (cb75ad5db 2021-02-10
• Your PyO3 version: 0.13.2
• Have you tried using latest PyO3 main (replace version = "0.x.y" with git = "https://github.com/PyO3/pyo3")?:

💥 Reproducing

Please provide a minimal working example. This means both the Rust code and the Python.

use pyo3::prelude::*;
use pyo3::wrap_pyfunction;

use std::future::Future;

#[pymodule]
pub fn robyn(py: Python<'_>, m: &PyModule) -> PyResult<()> {
    pyo3_asyncio::try_init(py).unwrap();
    pyo3::prepare_freethreaded_python();

    Ok(())
}

Error message:

error[E0425]: cannot find function `prepare_freethreaded_python` in crate `pyo3`
  --> src/lib.rs:29:11
   |
29 |     pyo3::prepare_freethreaded_python();
   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in `pyo3`

Please also write what exact flags are required to reproduce your results.

[mejrs]

That function is not available when compiling for PyPy - is that what you are running?

[davidhewitt]

It's also unavailable on 0.13.2 if your Python interpreter does not claim to have the Py_ENABLE_SHARED config var set. You can check:

>>> import sysconfig
>>> sysconfig.get_config_var("Py_ENABLE_SHARED")
1

If you don't get "1" output above, this could explain it.

We decided that disabling this API in this way was a mistake in #1553, so in the very-soon-to-be-released 0.14 or main you shouldn't experience this problem.

[sansyrox]

Thank you ,@davidhewitt ! Switching to main solved this issue. But , it has introduced a new issue.

-> src/process.rs:34:53
   |
34 |                 let contents: &str = output.extract(py).unwrap();
   |                                                     ^^ expected struct `pyo3::python::Python`, found struct `pyo3::Python`
   |
   = note: perhaps two different versions of crate `pyo3` are being used?

Any idea how do I fix it?

My cargo.toml file looks like this

[dependencies]
tokio = { version = "1.7.0", features = ["full"] }
dashmap = "4.0.2"
flume = "0.10.7"
pyo3 = {git = "https://github.com/PyO3/pyo3/",branch = "main", features = ["extension-module"]}

[davidhewitt]

Do you have pyo3 anywhere else in your dependencies? As the error suggests, you have two versions of pyo3 in use.

[sansyrox]

@davidhewitt , I am also using pyo3-asyncio. Is that a possible source of conflict?

[messense]

try patch instead

[dependencies]
pyo3 = { version = "0.13.2", features = ["extension-module"]}

[patch.crates-io]
pyo3 = {git = "https://github.com/PyO3/pyo3/",branch = "main", features = ["extension-module"]}

https://doc.rust-lang.org/edition-guide/rust-2018/cargo-and-crates-io/replacing-dependencies-with-patch.html

[sansyrox]

Thank you, @messense . Your solution works for me! 🥳

[davidhewitt]

Glad to hear. As the original problem has been solved, I'm going to close this issue out.