Compile error when compiling polars for python

Question

When compiling polars python package I get following error, any idea which version of rust should I use? Is there any workaround/fix for this?

I used following commands:

python -m pip install --no-binary :all: maturin
python -m pip install --no-binary :all: Polars==0.18.15

C:\Users\ashish.shirodkar>rustc --version
rustc 1.74.0-nightly (58eefc33a 2023-08-24)

Error:

   Compiling pyo3-built v0.4.7
         Compiling lz4 v1.24.0
         Compiling zstd v0.12.4
         Compiling parquet2 v0.17.2
         Compiling polars-error v0.32.0 (C:\Users\ashish.shirodkar\AppData\Local\Temp\pip-install-cor5irss\polars_180ec2d9ea9044ce86687698c1427599\local_dependencies\polars-error)
         Compiling polars-row v0.32.0 (C:\Users\ashish.shirodkar\AppData\Local\Temp\pip-install-cor5irss\polars_180ec2d9ea9044ce86687698c1427599\local_dependencies\polars-row)
      error: assigning to `&T` is undefined behavior, consider using an `UnsafeCell`
         --> local_dependencies\polars-core\src\chunked_array\ops\rolling_window.rs:120:29
          |
      96  |               let ptr = array_ptr.as_ref() as *const dyn Array as *mut dyn Array
          |  _______________________-
      97  | |                 as *mut PrimitiveArray<T::Native>;
          | |_________________________________________________- casting happend here
      ...
      120 |                               *ptr = arr_window;
          |                               ^^^^^^^^^^^^^^^^^
          |
          = note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
          = note: `#[deny(invalid_reference_casting)]` on by default

I tried using older rust versions but no luck.

Answer 1

I followed below steps as mentioned by @ritchie46 and it worked:

1. Get the version source code from GitHUB: https://github.com/pola-rs/polars/releases/tag/py-0.18.15

2. Install rust compiler from https://www.rust-lang.org/tools/install

3. Get the version of rust mentioned in rust-toolchain.toml in source downloaded from GitHub.

   rustup install nightly-2023-07-27
   rustup default nightly-2023-07-27-x86_64-pc-windows-msvc

   C:\Users\ashish.shirodkar>rustc --version
   rustc 1.73.0-nightly (0d95f9132 2023-07-26)

4. Execute following commands to compile and install Polars:

   python -m pip install --no-binary :all: maturin
   python -m pip install --no-binary :all: Polars==0.18.15