experimental-inspect: write nested package stubs into their own directory

[jonasdedden]

What was wrong

add_module_stub_files used a single module_path: &[&str] argument for two different things: the output directory and the list of parent module names. The recursive call passed [...ancestors, parent_name], which is right as parents and wrong as a directory. A package nested inside a package wrote its __init__.pyi under a directory named after its parent, its own name disappeared from the tree, and its leaf submodules landed one level too shallow.

pytests has no nested package, so nothing in the test suite exercised it.

Reproduction

#[pymodule]
pub mod grandchild {
    #[pyclass]
    pub struct Deep;
}

#[pymodule]
pub mod child {
    #[pymodule_export]
    use super::grandchild;
    #[pyclass]
    pub struct Mid;
}

#[pymodule]
mod slotrepro {
    #[pymodule_export]
    use super::child;
    #[pyclass]
    pub struct Top;
}

before                      after
__init__.pyi                __init__.pyi
slotrepro/__init__.pyi      child/__init__.pyi
slotrepro/grandchild.pyi    child/grandchild.pyi

The fix

Split the argument into directory: &Path and parents: &[&str]. The directory descends by the submodule's own name; parents accumulates module names exactly as before, so module_stubs and make_module_path_relative are unchanged in behaviour.

[Tpt]

Great catch! Thanks!