feat: update default windows compiler

[Glatzel]

references:

• https://github.com/conda-forge/conda-forge-pinning-feedstock/blob/main/recipe/conda_build_config.yaml

[Glatzel]

The error comes from upstream vc package and starts from vs2019_xxx. The expansion of temp(prefix) path in test in vc activate.bat exceeds 8192 characters.

https://github.com/conda-forge/vc-feedstock/blob/41025d6f35dbe5134294f7ad2cbca95a25b8ec65/recipe/activate.bat#L155-L159

https://learn.microsoft.com/en-us/troubleshoot/windows-client/shell-experience/command-line-string-limitation

[wolfv]

Hey @Glatzel I am not sure if we should really edit this ... I have asked on Zulip:

#build-tools > Updating the default compilers (Windows)

[Glatzel]

Hi @wolfv, I agree with removing the default bahavior of parsing ${{compiler('xxx')}} like thing.

But, it needs decision, if you think rattler-build concerns more about building for arbitrary build environment, not just conda-forge, removing the default compiler is reasonable. Just need to add docs the sample pin file/link(the one in conda-forge-pinning-feedstock is already good enough), users will add their own conda_build_config.yaml and have fully control over their own build workflow, just like a normal varient file, no black-box and implicit "magic".

If you decide to apply the no default compiler solution, just close this pr. I may try it to remove those compiler relate code and revise the doc. It could effect many tests and need some time, so no guarentee here.