Enhance changelog workflow to check for missing labels

Signed-off-by: Kunal Kotwani <kkotwani@amazon.com>

.github/workflows/changelog_verifier.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   # Enforces the update of a changelog file on every pull request
   verify-changelog:
-    if: github.repository == 'opensearch-project/OpenSearch'
+    # if: github.repository == 'opensearch-project/OpenSearch'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -26,6 +26,19 @@ jobs:
           changeLogPath: 'CHANGELOG.md'
         continue-on-error: true
       - run: |
+          # The check was possibly skipped leading to success for both the jobs
+          if [[ ${{ steps.verify-changelog-3x.outcome }} == 'success' && ${{ steps.verify-changelog.outcome }} == 'success' ]]; then
+            exit 0
+          fi
+          
           if [[ ${{ steps.verify-changelog-3x.outcome }} == 'failure' && ${{ steps.verify-changelog.outcome }} == 'failure' ]]; then
+            echo "error: Please ensure a changelog entry exists in CHANGELOG.md or CHANGELOG-3.0.md"
+            exit 1
+          fi
+          
+          # Concatenates the labels and checks if the string contains "backport"
+          has_backport_label=${{ contains(join(github.event.pull_request.labels.*.name, ', '), 'backport')}}
+          if [[ ${{ steps.verify-changelog.outcome }} == 'success' && $has_backport_label == false ]]; then
+            echo "error: Please make sure that the PR has a backport label associated with it when making an entry to the CHANGELOG.md file"
             exit 1
           fi

CHANGELOG-3.0.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Tracing for deep search path ([#12103](https://github.com/opensearch-project/OpenSearch/pull/12103))
 - Add explicit dependency to validatePom and generatePom tasks ([#12807](https://github.com/opensearch-project/OpenSearch/pull/12807))
 - Replace configureEach with all for publication iteration ([#12876](https://github.com/opensearch-project/OpenSearch/pull/12876))
+- Should not complain for this change
 
 ### Dependencies
 - Bump `log4j-core` from 2.18.0 to 2.19.0