[needs-design]Can we let macro generate function to append module to init table?

[herquan]

Hi,
In order to debug module sometimes we need to run a python script inside the rust environment. One way to do this is through calling function PyImport_AppendInittab before pyo3::prepare_freethreaded_python(). We don't have this in pyo3 directly but one workaround would be adding such piece of code

pub extern "C" fn pyinit() -> *mut ::pyo3::ffi::PyObject {
	unsafe { PyInit_module() }
}
pub fn append_inittab(){
	unsafe {
		pyo3::ffi::PyImport_AppendInittab("module\0".as_ptr() as *const std::os::raw::c_char, Option::Some(pyinit));
	}
}

And I'm thinking of adding such support in macro pymodule with similar code like

pub fn append_inittab_wrapper(){
    unsafe {
        #krate::ffi::PyImport_AppendInittab(concat!(stringify!(#name), "\0").as_ptr() as *const std::os::raw::c_char, Option::Some(pyinit));
    }
}

Meanwhile make sure PyImport_AppendInittab contains unsafe so this function can be reused. One thing I'm not sure is how to let the rust project that uses pyo3 recognize the append_inittab_wrapper without guessing the function name.
Please let me know if there is any concern for this or if there is any better idea?

[davidhewitt]

I would be ok with having a safe function PyModule::append_to_inittab(). It would probably make sense for it to panic if Py_IsInitialized() returns true.

[davidhewitt]

Actually maybe this would need to a a macro pyo3::append_to_inittab!(my_module) which uses the same kind of tricks done in wrap_pymodule. PRs to experiment with this are welcome!