crates_repository incorrectly resolves windows_x86_64_msvc for x86_64-pc-windows-gnu target

[drinktoomuchsax]

Problem

When cross-compiling for x86_64-pc-windows-gnu (MinGW) target from Linux, crates_repository
incorrectly selects windows_x86_64_msvc crate variants instead of windows_x86_64_gnu,
causing linking failures with .lib files.

Reproduction

1. Register x86_64-pc-windows-gnu in rust_register_toolchains(extra_target_triples=...)
2. Create a rust_binary with platform = "//platforms:windows-x86_64"
3. Build with MinGW linker (-C linker=x86_64-w64-mingw32-gcc)

Expected Behavior

Crates with platform-specific dependencies (like windows-sys) should resolve to
windows_x86_64_gnu variant when target_env = "gnu".

Actual Behavior

Links with MSVC libraries (.lib files), causing errors like:
x86_64-w64-mingw32-gcc: error: advapi32.lib: No such file or directory

Environment

• rules_rust: v0.48.0
• Bazel: 8.2.1
• Host: Linux x86_64 (WSL)
• Target: x86_64-pc-windows-gnu

Related Work

• PR Don't emit .pdb output files using mingw-gcc #1742 addresses MinGW .pdb files but doesn't solve crate dependency resolution
• Cargo correctly handles this by evaluating cfg(target_env = "gnu") conditions

Workaround

Currently using Cargo directly for Windows builds.

[dzbarsky]

Yes, the windows support in rules_rust is lacking and only the msvc ABI is really supported. This branch in my rules_rs ruleset properly handles toolchains for all windows ABIs, you may want to give it a try https://github.com/dzbarsky/rules_rs/tree/zbarsky/toolchains

Still experimental but feel free to file issues there if it doesn't work for tou

[drinktoomuchsax]

thanks a lot for answering, i will give it a try

[dzbarsky]

thanks a lot for answering, i will give it a try

That support has now been landed to the main branch of rules_rs and released. There's docs in the README as well