cargo llvm-cov unusable on the Rust build node: llvm-tools-preview cannot be installed (file conflict) #1559

cargo-llvm-cov 0.9.1 is installed on the node, but the active toolchain (rustc 1.98.1, LLVM 22.1.8) has no llvm-tools component. Running 'prod-code exec -- cargo llvm-cov --no-report --lib' makes cargo-llvm-cov call 'rustup component add llvm-tools-preview', which fails: failed to install component llvm-tools-preview-x86_64-unknown-linux-gnu, detected conflict: lib/rustlib/x86_64-unknown-linux-gnu/lib/libLLVM-22-rust-1.98.1-stable.so. The system llvm-cov/llvm-profdata are LLVM 14 and cannot read LLVM 22 profiles. Expected: coverage runs on the node (llvm-tools-preview installed for the active toolchain) or a code_coverage tool. Workaround: ran cargo llvm-cov locally with PROD_CODE_LOCAL=1.

Environment

• client: prod-code 0.3.41 (commit 9a21810) on macos aarch64
• node: linux x86_64 (prod-code 0.3.41, commit 9a21810), engines: rust (ra_ap_ide), go (gopls), cpp (clangd), python (basedpyright-langserver), typescript (tsc --lsp), generic-lsp

Filed with prod-code report-issue.