nogil VS RustPython

This might be a dumb question, but why would removing the GIL break FFI? Is it just that existing no-GIL implementations/proposals have discarded/ignored it, or is there a fundamental requirement, e.g. C programs unavoidably interact directly with the GIL? I know that the C-API is only stable between minor releases [0] compiled in the same manner [1], so it's not like the ecosystem is dependent upon it never changing.

I cannot seem to find much discussion about this. I have found a no-GIL interpreter that works with numpy, scikit, etc. [2][3] so it doesn't seem to be a hard limit. (That said, it was not stated if that particular no-GIL implementation requires specially built versions of C-API libs or if it's a drop-in replacement.)

[0]: https://docs.python.org/3/c-api/stable.html#c-api-stability

[1]: https://docs.python.org/3/c-api/stable.html#platform-conside...

[2]: https://github.com/colesbury/nogil

[3]: https://discuss.python.org/t/pep-703-making-the-global-inter...

https://github.com/colesbury/nogil does manage to get rid of the GIL, but it's not certain to make it into Python core. The main problem is the amount of existing libraries that depend on the existence of the GIL without realizing it - breaking those would be extremely disruptive.

CPython is also investigating the removal of the GIL (PEP703, nogil). I think requiring the GIL is a wider thing that libraries will need to address anyway. But also, for the same reason as above I'd be surprised if the Modular team thought that saying "you can run all your python code unchanged" was a good idea if there was a secret "except for code that uses numpy" muttered under the breath.

I'm worried about the speedup

My understanding is that it's based on the most recent attempt to remove the GIL by Sam Gross

https://github.com/colesbury/nogil

In addition to some ways to try to not have nogil have as much overhead he added a lot of unrelated speed improvements so that python without the gil would still be faster not slower in single thread mode. They seem to have merged those performance patches first that means if they add his Gil removal patches in say python 3.12 it will still be substantially slower then 3.11 although faster then 3.10. I hope that doesn't stop them from removing the gil (at least by default)

Looks like it's still active to me:

https://github.com/colesbury/nogil/

Integrating Rust into Python, Edward Wright, 2021-04-12 Examples for making rustpython run actual python code Calling Rust from Python using PyO3 Writing Python inside your Rust code — Part 1, 2020-04-17 RustPython, RustPython Rust for Python developers: Using Rust to optimize your Python code PyO3 (Rust bindings for Python) Musing About Pythonic Design Patterns In Rust, Teddy Rendahl, 2023-07-14

No.

…and this one is no exception -> https://github.com/RustPython/RustPython/issues/1940

Packages that rely on c dependencies like numpy, etc. only work if you write a custom implementation by hand; the “normal” package flat out doesn’t (and cannot) work.

The title would be accurate if this project (https://rustpython.github.io/) was becoming the official version of Python.

If you absolutely need something comparable to Sympy, then one option might be to figure out how to best call Sympy from Rust. e.g. - RustPython, although it seems like Sympy isn't supported yet - Pyodide, and figuring out how to run it outside of a web browser. Probably also not very easy. - PyPy, and having a pretty simple Python binary for every platform - ...

I'm actually rooting for RustPython to reach a level of maturity that we'd just be able to ship apis and stuff with it.... https://github.com/RustPython/RustPython

Good question and it also actual for: python 3.12, RustPython and xonsh binary.

RustPython – A Python Interpreter written in Rust