Maturin build fails with --sdist, succeeds without

[Bluesy1]

Bug Description

I was updating my project from maturing 0.13.7 to 0.14.1, and as such, i was trying to update my code to take advantage of some new things I noticed in the docs for maturin.
When i was updating my pyproject.toml for my mixed python+rust project, i added the following lines, and after that trying to build with the --sdist flag fails, saying maturin crashed.

[tool.maturin]
python-source = "python"

Generated report file

Your Python version (python -V)

Python 3.11.0

Your pip version (pip -V)

pip 22.3.1

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

1. Take a working mixed python rust project and add the folowing lines:

[tool.maturin]
python-source = "python"

2. Observe maturin crashes when trying to build with the --sdist flag
   Generated output from adding RUST_LOG=maturin=debug to the front of the call

[messense]

So the crashed code is

maturin/src/source_distribution.rs

Line 557 in 3cfd886

let target = root_dir.join(source.strip_prefix(pyproject_dir).unwrap());

Is your code public that I can reproduce this issue from it?

[Bluesy1]

@messense yeah! its a little behind what i have locally, but you can find it here: https://github.com/Bluesy1/CharB0T/tree/main/charbot_rust

[messense]

That doesn't include the python-source = "python" change, can you push your changes to a branch?

[Bluesy1]

Done, https://github.com/Bluesy1/CharB0T/tree/refractor/rust-maturin-0.14/charbot_rust

[Bluesy1]

Thanks for the quick look and fix on this!