Enhance workflow to get PR info before checkout

Added steps to retrieve pull request information before checking out the PR head.

Author: nixel2007

.github/workflows/build-bootJar-on-comment.yaml

@@ -19,9 +19,30 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Checkout repository with full history
-        uses: actions/checkout@v4
+      - name: Get PR info
+        id: pr
+        uses: actions/github-script@v7
         with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const prNumber = context.issue.number;
+            const pr = await github.rest.pulls.get({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: prNumber,
+            });
+
+            core.info(`Base: ${pr.data.base.repo.full_name}@${pr.data.base.ref}`);
+            core.info(`Head: ${pr.data.head.repo.full_name}@${pr.data.head.ref}`);
+
+            core.setOutput('head_ref', pr.data.head.ref);
+            core.setOutput('head_repo', pr.data.head.repo.full_name);
+
+      - name: Checkout PR head with full history
+        uses: actions/checkout@v5
+        with:
+          repository: ${{ steps.pr.outputs.head_repo }}
+          ref: ${{ steps.pr.outputs.head_ref }}
           fetch-depth: 0
           fetch-tags: true