Bug Description

The new maturin v1.3.0 now panics on our project:

Platform: macos aarch64
Version: 1.3.0
Args: /Users/jer/mozilla/src/glean/.venv3.11/bin/maturin develop

thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', src/module_writer.rs:875:50
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
make: *** [Makefile:46: build-python] Error 101

The unwrap happens here:

root_package is not guaranteed to exist.
v1.2.3 works just fine for us.

Your maturin version (maturin --version)

1.3.0

Your Python version (python -V)

3.11.5

Your pip version (pip -V)

23.2.1

What bindings you're using

uniffi

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

1. git clone https://github.com/mozilla/glean && cd glean
2. make build-python