How to generate .pyi files?

[wangzhen0518]

I followed the tutorial in https://pyo3.rs/v0.27.1/type-stub.html. Here is my code:

// src/lib.rs
use pyo3::prelude::*;

#[pymodule]
pub mod example {
    use pyo3::prelude::*;

    #[pymodule_export]
    pub const CONSTANT: &str = "FOO";

    #[pyclass(eq)]
    #[derive(Eq, PartialEq)]
    struct Class {
        value: usize,
    }

    #[pymethods]
    impl Class {
        #[new]
        fn new(value: usize) -> Self {
            Self { value }
        }

        #[getter]
        fn value(&self) -> usize {
            self.value
        }
    }

    #[pyfunction]
    #[pyo3(signature = (arg: "list[int]") -> "list[int]")]
    fn list_of_int_identity(arg: Bound<'_, PyAny>) -> Bound<'_, PyAny> {
        arg
    }
}

# Cargo.toml
[package]
name = "example"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[lib]
name = "example"
crate-type = ["cdylib"]

[dependencies]
pyo3 = { version = "0.27.1", features = [ "experimental-inspect" ] }

The compilation command is:

maturin develop

However, the generated files only contain .so and __init__.py, but no .pyi files. I also have read the issues about stub files generation, e.g., #5137, #3977, but I am not familiar with .pyi, "introspection fragments" and many other conceptions. Does pyo3 now only support generating introspection fragments and not generating .pyi files?

I noticed there was a related discussion #2330, but it's quite outdated.