fix: correctly handle pull_request_target event (#1327)

* Fix workflow on pull_request_target

* fix fromJSON

.github/workflows/validate-formatting.yaml

@@ -18,6 +18,7 @@ jobs:
 
     steps:
       - name: Get pull request information
+        if: github.event_name == 'pull_request_target'
         uses: actions/github-script@v7
         id: pr
         with:
@@ -32,13 +33,13 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: 0 # Ensure the full history is fetched for accurate diffing
-          ref: ${{ fromJSON(steps.pr.outputs.result).merge_commit_sha }}
+          ref: ${{ github.event_name == 'pull_request_target' && fromJSON(steps.pr.outputs.result).merge_commit_sha || '' }}
 
       - name: Get changed files
         id: changed-files
         run: |
           if ${{ github.event_name == 'pull_request' }}; then
-              echo "files=$(git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.sha }} | grep -E '\.(sh|func)$' | xargs)" >> $GITHUB_OUTPUT
+              echo "files=$(git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ steps.pr.outputs.result && fromJSON(steps.pr.outputs.result).merge_commit_sha }} | grep -E '\.(sh|func)$' | xargs)" >> $GITHUB_OUTPUT
           else
               echo "files=$(git diff --name-only ${{ github.event.before }} ${{ github.event.after }} | grep -E '\.(sh|func)$' | xargs)" >> $GITHUB_OUTPUT
           fi