chore: debug failure when run manually

.github/workflows/e2ePerformanceTests.yml

@@ -32,6 +32,24 @@ jobs:
         with:
           fetch-depth: 0  # Fetches the entire history
 
+      - name: Determine "baseline ref" (prev merge commit)
+        id: getBaselineRef
+        run: |
+          # Get the name of the current branch
+          current_branch=$(git rev-parse --abbrev-ref HEAD)
+
+          echo "$current_branch"
+
+          if [ "$current_branch" = "main" ]; then
+            # On the main branch, find the previous merge commit
+            previous_merge=$(git rev-list --merges HEAD~1 | head -n 1)
+          else
+            # On a feature branch, find the common ancestor of the current branch and main
+            previous_merge=$(git merge-base HEAD main)
+          fi
+          echo "$previous_merge"
+          echo "BASELINE_REF=$previous_merge" >> "$GITHUB_OUTPUT"
+
       - name: Get pull request details
         id: getPullRequestDetails
         uses: ./.github/actions/javascript/getPullRequestDetails