NIFI-15794 Changed single commit check to opened action

Author: exceptionfactory

.github/scripts/build/validate-single-commit.sh

@@ -21,7 +21,7 @@ set -e
 
 if [ "${COMMIT_COUNT}" -eq 1 ]; then
   echo "Pull request contains a single commit"
-else
+else if [ "${GITHUB_EVENT_ACTION}" == "opened" ]; then
   echo "::error::Pull request contains ${COMMIT_COUNT} commits. Squash commits into a single commit for initial review."
   exit 1
 fi

.github/workflows/build.yml

@@ -105,7 +105,16 @@ jobs:
         continue-on-error: true
         env:
           COMMIT_COUNT: ${{ github.event.pull_request.commits }}
+          GITHUB_EVENT_ACTION: ${{ github.event.action }}
         run: .github/scripts/build/validate-single-commit.sh
+      - name: Evaluate Validation Results
+        env:
+          VALIDATION_FAILED: ${{ contains(steps.*.outcome, 'failure') }}
+        run: |
+          if [[ "${VALIDATION_FAILED}" == "true" ]]; then
+            echo "::error::Pull request validation failed"
+            exit 1
+          fi
 
   ubuntu-build-en:
     timeout-minutes: 120