import_hook doesn't rebuild and reinstall the package if the Rust code changes

[itamarst]

Bug Description

If I edit the Rust source code I am importing with maturin.import_hook, I would expect that a new Python process would rebuild the code when importing in the new process. Instead, the package is only ever compiled once.

Your maturin version (maturin --version)

1.1.0

Your Python version (python -V)

3.11.4

Your pip version (pip -V)

23.2

What bindings you're using

pyo3

Does cargo build work?

• Yes, it works

If on windows, have you checked that you aren't accidentally using unix path (those with the forward slash /)?

• Yes

Steps to Reproduce

I have a rust_pointvec.rs with PyO3 module defined.

I run:

import maturin.import_hook
maturin.import_hook.install()
import rust_pointvec

It compiles and installs.

I then modify the Rust code, and rerun the Python script. No rebuild or recompilation happens, the old compiled module is imported, and there is no maturin logging, unlike the initial run.

My guess at the problem: now that the package is installed, the import hook is bypassed since it can just use the default importer. Perhaps instead of sys.meta_path.append() the hook should be inserted earlier in sys.meta_path, e.g. rustimport makes sure to be first: https://github.com/mityax/rustimport/blob/master/rustimport/import_hook.py#L65C2-L65C2

[messense]

Thanks for the report, pull requests are welcome.