Switch CI to use merge queue

Author: Kobzol

.github/workflows/ci.yml

@@ -1,7 +1,7 @@
 name: CI
 on:
-  push: {}
-  pull_request: {}
+  pull_request:
+  merge_group:
 
 env:
   AWS_ACCESS_KEY_ID: AKIA46X5W6CZEAQSMRH7
@@ -30,9 +30,10 @@ jobs:
       - name: Check formatting
         run: cargo fmt --all --check
 
-  ci:
-    name: CI
+  deploy:
+    name: Deploy
     runs-on: ubuntu-latest
+    if: github.event_name == 'merge_group'
     steps:
       - name: Checkout the source code
         uses: actions/checkout@v4
@@ -50,4 +51,22 @@ jobs:
           redeploy_ecs_service: triagebot
           aws_access_key_id: "${{ env.AWS_ACCESS_KEY_ID }}"
           aws_secret_access_key: "${{ secrets.AWS_SECRET_ACCESS_KEY }}"
-        if: github.ref == 'refs/heads/master'
+
+  # Summary job for the merge queue.
+  # ALL THE PREVIOUS JOBS NEED TO BE ADDED TO THE `needs` SECTION OF THIS JOB!
+  ci:
+    needs: [ test, deploy ]
+    # We need to ensure this job does *not* get skipped if its dependencies fail,
+    # because a skipped job is considered a success by GitHub. So we have to
+    # overwrite `if:`. We use `!cancelled()` to ensure the job does still not get run
+    # when the workflow is canceled manually.
+    if: ${{ !cancelled() }}
+    runs-on: ubuntu-latest
+    steps:
+      # Manually check the status of all dependencies. `if: failure()` does not work.
+      - name: Conclusion
+        run: |
+          # Print the dependent jobs to see them in the CI log
+          jq -C <<< '${{ toJson(needs) }}'
+          # Check if all jobs that we depend on (in the needs array) were successful.
+          jq --exit-status 'all(.result == "success" or .result == "skipped")' <<< '${{ toJson(needs) }}'