x.py in rust-lang/rust does not like being called by rust-analyzer

[jyn514]

[ERROR rust_analyzer::reload] failed to switch build data: cargo check failed:
error: failed to run custom build command for `bootstrap v0.0.0 (C:\Users\Joshua Nelson\src\rust\src\bootstrap)`

Caused by:
  process didn't exit successfully: `c:\Users\Joshua Nelson\src\rust\target\debug\build\bootstrap-4864c5f723b632c4\build-script-build` (exit code: 101)
  --- stdout
  cargo:rerun-if-changed=build.rs
  cargo:rustc-env=BUILD_TRIPLE=x86_64-pc-windows-msvc

  --- stderr
  thread 'main' panicked at 'assertion failed: rustc.is_absolute()', src\bootstrap\build.rs:20:5

[jyn514]

It looks like rust-analyzer is calling it with the env variable RUSTC set to rustc. I don't know why it would do that, bootstrap is not built with any rustc on the host PATH.

[bjorn3]

RUSTC_WRAPPER is set to point to rust-analyzer. This will cause cargo to call rust-analyzer rustc instead of $RUSTC and not rust-analyzer $RUSTC I think. Rust-analyzer simply uses the second argument as command to run. (rustc in this case) The RUSTC_WRAPPER is part of the code that allows building proc macros and running build scripts and getting their output (generated code, env vars, ...) without doing a full cargo check run. This was implemented in #8476.

[flodiebold]

This can be disabled with rust-analyzer.cargo.useRustcWrapperForBuildScripts, but I don't think we should be running it at all if you've got proc macros and build scripts disabled 🤔

[flodiebold]

@jyn514 do you have runBuildScripts and procMacros disabled like in the suggested settings? Note that the defaults for this changed somewhat recently.

[jyn514]

Thanks! That worked around the issue, and now I just have the cyclic deps error (#8330). I suspect this is a duplicate of #9201 like you said.