[R-pkg-devel] Is there an Rtools40 changelog?

[James Lamb]

Hello,

I am a maintainer on the LightGBM project, focused on that project's R
package. The R package is not available on CRAN yet (we are working on it),
so for now our users must build it from source.

The package includes compilation of a C++ library, and we link to R.dll /
R.so to use R-provided functions like Rprintf.

With the release of R4.0 and Rtools40, we recently received reports from
our users that they are unable to build our package on Windows systems with
R 4.0 and Rtools 4.0 (https://github.com/microsoft/LightGBM/issues/3064).

After some investigation, I've learned that the following changes in
Rtools40 (relative to Rtools35) broke our installation process:

   - *gendef.exe* was removed
   - *mingw32-make.exe* was removed
   - paths like "mingw_64/bin" were changed to "mingw64/bin"

I do not expect that our off-CRAN installation process is supported. I
understand that by maintaining our own process, we are taking on the burden
of keeping up with new releases of R and Rtools.

My question is this...is there public documentation about why the changes I
mentioned above were made? I have not found any mention of them in the
following places, and am not sure where else to look.

   - https://cran.r-project.org/bin/windows/Rtools/
   - https://github.com/r-windows/docs/blob/master/faq.md#readme
   - https://jeroen.github.io/rstudio2019

Thank you very much for your time and consideration,

-James Lamb

	[[alternative HTML version deleted]]