x.py check fails on enzyme build step

[ZuseZ4]

Summary

Command used

./configure --enable-llvm-link-shared --enable-llvm-plugins --enable-llvm-enzyme --release-channel=nightly --enable-llvm-assertions --enable-clang --enable-lld --enable-option-checking --enable-ninja --disable-docs

./x.py build --stage 1 library

./x.py check

Expected behaviour

runs a check build

Actual behaviour

Checking stage0 library artifacts (x86_64-unknown-linux-gnu)
    Finished `release` profile [optimized] target(s) in 0.02s

thread 'main' panicked at src/bootstrap/src/core/build_steps/compile.rs:1198:73:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Build completed unsuccessfully in 0:00:23

Bootstrap configuration (bootstrap.toml)

./configure --enable-llvm-link-shared --enable-llvm-plugins --enable-llvm-enzyme --release-channel=nightly --enable-llvm-assertions --enable-clang --enable-lld --enable-option-checking --enable-ninja --disable-docs

Operating system

Ubuntu 22.04

HEAD

Additional context

Build Log

<log>

cc @onur-ozkan since you helped with bootstrap before.
I improved the code a bit here https://github.com/rust-lang/rust/pull/136428/files#diff-5a1e05f2688d271039171a547d407d0c8a96715ee64d35562fc76b4c9a874303 and you improved it here: #130648

I feel like this worked before and probably regressed, but I'm not 100% sure. I guess I need to add a rustc_check boolean to rustc_cargo and skip the code for both check_runs and dry runs?

[onur-ozkan]

Replacing the dry-run check with if let Some(llvm_config) = ... might make more sense. I'm not sure if it works in all cases but it's worth a try. If it doesn't work, you can do the if let Some(llvm_config) = ... thing inside a dry-run check.