Merge pull request #173502 from Homebrew/fix-automerge-from-merge_queue

automerge-from-merge-queue: fix

.github/workflows/automerge-from-merge-queue.yml

@@ -56,9 +56,13 @@ jobs:
                 ... on WorkflowRun {
                   checkSuite {
                     commit {
-                      associatedPullRequests(last: 1) {
+                      parents(last: 2) {
                         nodes {
-                          number
+                          associatedPullRequests(last: 1) {
+                            nodes {
+                              number
+                            }
+                          }
                         }
                       }
                     }
@@ -67,12 +71,21 @@ jobs:
               }
             }
         run: |
+          # Get the latest PR associated with the second parent of the merge commit created for the merge_group.
           number="$(
             gh api graphql \
               --field url="$WORKFLOW_RUN_URL" \
               --raw-field query="$QUERY" \
-              --jq '.data.resource.checkSuite.commit.associatedPullRequests.nodes[].number'
+              --jq '.data.resource.checkSuite.commit.parents.nodes |
+                      last.associatedPullRequests.nodes[].number'
           )"
+
+          if [[ -z "$number" ]]
+          then
+            echo "::error::Missing PR number!"
+            exit 1
+          fi
+
           echo "number=$number" >> "$GITHUB_OUTPUT"
 
       - name: Check PR labels and timeline for merge queue events