Bootstrap test ci_rustc_if_unchanged_logic fails locally

[ehuss]

Summary

The test ci_rustc_if_unchanged_logic fails if you are working on a branch that has any changes to library or compiler with:

---- core::builder::tests::ci_rustc_if_unchanged_logic stdout ----
Creating a sysroot for stage2 compiler (use `rustup toolchain link 'name' build/host/stage2`)
Building stage2 library artifacts (x86_64-unknown-linux-gnu)

thread 'core::builder::tests::ci_rustc_if_unchanged_logic' panicked at src/bootstrap/src/core/builder/tests.rs:267:9:
CI-rustc can't be used with 'if-unchanged' while there are changes in compiler and/or library.
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    core::builder::tests::ci_rustc_if_unchanged_logic

This makes it difficult to run tests locally. For example, running the x86_64-gnu docker image fails with this message.

I'm not entirely clear how this test works in CI, but it would be helpful if it didn't fail for local testing.

Command used

./x test bootstrap

or

 cargo run --manifest-path src/ci/citool/Cargo.toml run-local x86_64-gnu

Expected behaviour

Command should pass.

Actual behaviour

Test fails.

Bootstrap configuration (config.toml)

No config (use all defaults), or use the config in the x86_64-gnu image.

Operating system

Any

HEAD

39d5d92

[onur-ozkan]

The error message is pretty clear and it should never trigger when you have changes on compiler or library tree. I tried to reproduce it by adding dummy commit on compiler tree but x test bootstrap still did not fail.

[ehuss]

Hm, the following exact steps fail for me:

git clone https://github.com/rust-lang/rust.git
cd rust
git checkout -b bootstrap-test
echo "// test" >> library/std/src/lib.rs
git add library/std/src/lib.rs
git commit -m test
./x test bootstrap

Does that not fail for you?

[onur-ozkan]

That failed, yeah. I think the reason is that we allow using ci-rustc in non-CI environments when the library changes but the compiler doesn't (to make library development easier). I will stabilize the test and send a fix PR in couple minutes.

[onur-ozkan]

If you can confirm that #138245 fixes this issue, that would be great.

[ehuss]

Yea, that works, thanks!