The RUSTC_WORKSPACE_WRAPPER case does not work if the wrapper is called rustc

[nagisa]

I’m trying to set up sccache and I have a wrapper script at a location scripts/coverage-wrappers/rustc that I set RUSTC_WORKSPACE_WRAPPER to.

Cargo then invokes $RUSTC_WRAPPER $RUSTC_WORKSPACE_WRAPPER $RUSTC "$@", sccache compiler detection code notices that $RUSTC_WORKSPACE_WRAPPER is named rustc and tries to invoke $RUSTC_WORKSPACE_WRAPPER -v which naturally fails, because the first argument ain’t $RUSTC as expected by the wrapper.

I think detection logic should be adjusted to check if the first argument to sccache is actually the same thing as $RUSTC_WORKSPACE_WRAPPER and then use the next argument to query version. Or a possible alternative is to invoke $RUSTC_WORKSPACE_WRAPPER $RUSTC ${SCCACHE_ARGS}.

[nagisa]

Another problem, even when I had renamed the wrapper script to something else than rustc I would still see an error when running cargo build

  cargo build --locked --profile dev-release -p neard --bin neard
  shell: /usr/bin/bash -e {0}
  env:
    CI_HACKS: 1
    pythonLocation: /opt/hostedtoolcache/Python/3.11.7/x64
    PKG_CONFIG_PATH: /opt/hostedtoolcache/Python/3.11.7/x64/lib/pkgconfig
    Python_ROOT_DIR: /opt/hostedtoolcache/Python/3.11.7/x64
    Python2_ROOT_DIR: /opt/hostedtoolcache/Python/3.11.7/x64
    Python3_ROOT_DIR: /opt/hostedtoolcache/Python/3.11.7/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.11.7/x64/lib
    SCCACHE_PATH: /opt/hostedtoolcache/sccache/0.7.5/x64/sccache
    ACTIONS_CACHE_URL: https://acghubeus1.actions.githubusercontent.com/Gv3ljlJl5EjEbK2TmdZ8BXVzVUjRQhtIvr6X7PmTEjRmsGZMxp/
    ACTIONS_RUNTIME_TOKEN: ***
    SCCACHE_GHA_ENABLED: true
    RUSTC_WRAPPER: sccache
    LLVM_PROFILE_FILE: /home/runner/work/nearcore/nearcore/target/nearcore-%p-%4m.profraw
    CARGO_LLVM_COV: 1
    CARGO_LLVM_COV_SHOW_ENV: 1
    CARGO_LLVM_COV_TARGET_DIR: /home/runner/work/nearcore/nearcore/target
    RUSTC_WORKSPACE_WRAPPER: /home/runner/work/nearcore/nearcore/scripts/coverage-wrapper-rustc
error: failed to run `rustc` to learn about target-specific information

Caused by:
  process didn't exit successfully: `sccache /home/runner/work/nearcore/nearcore/scripts/coverage-wrapper-rustc /home/runner/.rustup/toolchains/1.75.0-x86_64-unknown-linux-gnu/bin/rustc - --crate-name ___ --print=file-names -Cforce-unwind-tables=y --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=sysroot --print=split-debuginfo --print=crate-name --print=cfg` (exit status: 2)
  --- stderr
  sccache: error: failed to execute compile
  sccache: caused by: Compiler not supported: "/home/runner/work/nearcore/nearcore/scripts/coverage-wrapper-rustc: line 9: exec: -E: invalid option\nexec: usage: exec [-cl] [-a name] [command [argument ...]] [redirection ...]\n"

Only after I manually set $CARGO=1 did things started chugging along, which suggests to me that perhaps cargo isn’t always setting $CARGO environment variable? Might be bug in cargo too, though. Not sure.