misc: Check for Change-Id in GitHub Actions

This adds a check to our continous integration tests that ensures
that every single commit in a pull request has a Change-Id, and
instructs you to add one if that check fails.  This ensures all
commits on GitHub are still compatible with Gerrit.

Change-Id: I3fd753da5ab3ca6d6334a8e0eb574433aa1ca589
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/72118
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
diff --git a/.github/workflows/ci-tests.yaml b/.github/workflows/ci-tests.yaml
index 61ba4b5..c3188b8 100644
--- a/.github/workflows/ci-tests.yaml
+++ b/.github/workflows/ci-tests.yaml
@@ -16,10 +16,33 @@
     - uses: actions/setup-python@v3
     - uses: pre-commit/action@v3.0.0
 
+  # ensures we have a change-id in every commit, needed for gerrit
+  check-for-change-id:
+    # runs on github hosted runner
+    runs-on: ubuntu-latest
+    container: gcr.io/gem5-test/ubuntu-22.04_all-dependencies:latest
+    steps:
+      - uses: actions/github-script@v6
+        env:
+          token: "Change-Id"
+          pattern: ".*"
+        with:
+          script: |
+            const commits = ${{ toJSON(github.event.commits) }}
+            for (const commit of commits) {
+              const id = "Change-Id: "
+              const message = commit.message;
+              if (!message.includes(id)) {
+                core.setFailed('One or more of the commits in this pull request is missing a Change-ID, which we require for any changes made to gem5. ' +
+                'To automatically insert one, run the following:\n f=`git rev-parse --git-dir`/hooks/commit-msg ; mkdir -p $(dirname $f) ; ' +
+                'curl -Lo $f https://gerrit-review.googlesource.com/tools/hooks/commit-msg ; chmod +x $f\n Then amend the commit with git commit --amend --no-edit, and update your pull request.')
+              }
+            }
+
   build-gem5:
     runs-on: [self-hosted, linux, x64, build]
     container: gcr.io/gem5-test/ubuntu-22.04_all-dependencies:latest
-    needs: pre-commit # only runs if pre-commit passes
+    needs: [pre-commit, check-for-change-id] # only runs if pre-commit and change-id passes
     outputs:
       artifactname: ${{ steps.name.outputs.test }}
     steps:
@@ -39,7 +62,7 @@
   unittests-all-opt:
     runs-on: [self-hosted, linux, x64, run]
     container: gcr.io/gem5-test/ubuntu-22.04_all-dependencies:latest
-    needs: pre-commit # only runs if pre-commit passes
+    needs: [pre-commit, check-for-change-id] # only runs if pre-commit and change-id passes
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v3
@@ -51,7 +74,7 @@
   testlib-quick:
     runs-on: [self-hosted, linux, x64, run]
     container: gcr.io/gem5-test/ubuntu-22.04_all-dependencies:latest
-    needs: [pre-commit, build-gem5]
+    needs: [pre-commit, check-for-change-id, build-gem5]
     timeout-minutes: 360     # 6 hours
     steps:
       - uses: actions/checkout@v3