Auto merge of #131531 - onur-ozkan:move-dummy-commit, r=Kobzol

move dummy commit logic into x86_64-gnu-llvm-18

Doing the dummy commit logic in a runner that uses CI-LLVM breaks in merge CI. This should be properly fixed by https://github.com/rust-lang/rust/pull/131358 (see the [actual problem](https://github.com/rust-lang/rust/pull/131448#issuecomment-2406516261)). Since we can also fix it by moving the dummy commit into the runner where we use in-tree LLVM, so why not do that as well?

1 files changed, 16 insertions, 0 deletions

diff --git a/src/ci/docker/scripts/x86_64-gnu-llvm.sh b/src/ci/docker/scripts/x86_64-gnu-llvm.sh
index 98290f5a72c..dea38b6fd2a 100755
--- a/src/ci/docker/scripts/x86_64-gnu-llvm.sh
+++ b/src/ci/docker/scripts/x86_64-gnu-llvm.sh
@@ -2,6 +2,22 @@
 
 set -ex
 
+if [ "$READ_ONLY_SRC" = "0" ]; then
+    # `core::builder::tests::ci_rustc_if_unchanged_logic` bootstrap test ensures that
+    # "download-rustc=if-unchanged" logic don't use CI rustc while there are changes on
+    # compiler and/or library. Here we are adding a dummy commit on compiler and running
+    # that test to make sure we never download CI rustc with a change on the compiler tree.
+    echo "" >> ../compiler/rustc/src/main.rs
+    git config --global user.email "dummy@dummy.com"
+    git config --global user.name "dummy"
+    git add ../compiler/rustc/src/main.rs
+    git commit -m "test commit for rust.download-rustc=if-unchanged logic"
+    DISABLE_CI_RUSTC_IF_INCOMPATIBLE=0 ../x.py test bootstrap \
+        -- core::builder::tests::ci_rustc_if_unchanged_logic
+    # Revert the dummy commit
+    git reset --hard HEAD~1
+fi
+
 # Only run the stage 1 tests on merges, not on PR CI jobs.
 if [[ -z "${PR_CI_JOB}" ]]; then
     ../x.py --stage 1 test --skip src/tools/tidy