[R-pkg-devel] Rust 1.70 and build failures on Windows

[Hiroaki Yutani]

Correction: GitHub Actions already uses the latest version of Rtools43, so
it should be no problem. I sincerely apologize to those who got confused
and the maintainer of r-lib/actions for spreading the wrong information.

Best,
Yutani

2023年6月8日(木) 18:06 Hiroaki Yutani <yutani.ini using gmail.com>:

> Hi,
>
> This is a quick notice for developers of R packages using Rust.
>
> Rust 1.70 was released on June 1st, 2023 [1]. If you use Rust in your R
> package,
> you'll probably start to see an error and a warning on the final linking
> step of
> Windows builds.
>
> ## Error
>
> The first thing you'll notice is that linking fails with errors like this
> one:
>
>     ...snip...\std\src\sys\windows/handle.rs:290: undefined reference to
> `NtWriteFile'
>
> This is because Rust 1.70 started to use several Windows APIs defined in
> NTDLL.DLL [2]. So, this can be easily fixed by adding `-ltdll` to
> `PKG_LIBS`.
>
>     PKG_LIBS = ...snip... -lntdll
>
>
> ## Warning
>
> This one is a bit tricky, After modifying `PKG_LIBS`, your build should
> succeed,
> but you might or might not see a lot of warnings like this one:
>
>     Warning: corrupt .drectve at end of def file
>
> This is because Rust 1.70 upgraded LLVM to version 16, and LLVM generates a
> binary containing directives that only the very latest version (2.40) of
> GNU
> linker can understand [3]. What's fortunate is that the latest Rtools43
> uses
> binutils 2.40, so this warning won't happen if you target only R >= 4.3.
> However, the following cases might be a problem:
>
>     1. On R < 4.3
>     2. On R >= 4.3 with outdated Rtools43 (currently, it's the case on
> GitHub Actions [4])
>
> Unfortunately, it seems there's no option to suppress this warning, so
> there's
> no way to save `R CMD check` from failing if you run it with `--as-cran`.
> In
> other words, if you are a maintainer of some R package on CRAN, you might
> need
> to consider giving up your package on oldrel when the CRAN Windows server
> upgrades
> Rust (I heard the current installed version is 1.69, but I'm not sure).
>
> For non-CRAN packages, I think you can ignore the warnings. The directive
> is to
> reduce the number of exported symbols in order to prevent overflow [5], so
> it
> should be fine if it doesn't overflow in actual. But, I'm not an expert
> here,
> so please decide at your own risk.
>
> Hope this helps.
>
> Best,
> Yutani
>
> [1]: https://blog.rust-lang.org/2023/06/01/Rust-1.70.0.html
> [2]:
> https://en.wikipedia.org/wiki/Microsoft_Windows_library_files#NTDLL.DLL
> [3]:
> https://github.com/rust-lang/rust/issues/112368#issuecomment-1581917714
> [4]: https://github.com/r-lib/actions/issues/734
> [5]:
> https://github.com/llvm/llvm-project/commit/c5b3de6745c37dd991430b9b88ff97c35b6fc455
>

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