Issue checkstyle#15567: Fix the new workflow and Optimise it

.github/workflows/regression-report.yml

@@ -349,7 +349,6 @@ jobs:
         || needs.handle_configs_in_pr_description.result == 'success')
     runs-on: ubuntu-latest
     outputs:
-      download_files_failed: ${{ steps.download_files.outputs.failed }}
       branch: ${{ steps.set_branch.outputs.ref }}
       commit_sha: ${{ steps.set_branch.outputs.commit_sha }}
     steps:
@@ -557,38 +556,60 @@ jobs:
   # should be always last step
   send_message:
     runs-on: ubuntu-latest
-    needs: [ check_pr_status, parse_comment, download_configs, make_report ]
-    if: failure() || success()
+    needs: [
+      handle_generated_config_bundle,
+      download_configs,
+      make_report ]
+    if: always()
+      && (needs.make_report.outputs.message != ''
+          || needs.download_configs.result == 'failure'
+          || needs.handle_generated_config_bundle.result == 'failure')
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
       - name: Get message
         env:
           MSG: ${{ needs.make_report.outputs.message }}
-          DOWNLOAD_FAILED: ${{ needs.download_configs.outputs.download_files_failed }}
+          DOWNLOAD_RESULT: ${{ needs.download_configs.result }}
+          GENERATED_CONFIG_RESULT: ${{ needs.handle_generated_config_bundle.result }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
           mkdir -p .ci-temp
           JOBS_LINK="https://github.com/checkstyle/checkstyle/actions/runs/${{github.run_id}}"
-          if [ "$DOWNLOAD_FAILED" == "true" ]; then
-            echo "Report generation failed. Please use 'GitHub, generate report for" \
-                 "check_name/example_type'<br>Link: $JOBS_LINK" > .ci-temp/message
+          if [ "$DOWNLOAD_RESULT" == "failure" ]; then
+            {
+              echo "Failed to download or process the specified configuration(s)."
+              echo "Error details: $DOWNLOAD_ERROR"
+              echo "<br>Please ensure you've used one of the following commands correctly:"
+              echo "- 'GitHub, generate report for <config_name>'"
+              echo "- 'GitHub, generate report by config from <file_path>'"
+              echo "- 'GitHub, generate report for configs in PR description'"
+              echo "<br>And check that all specified configs or files exist and are valid."
+              echo "<br>Link: $JOBS_LINK"
+            } > .ci-temp/message
+          elif [ "$GENERATED_CONFIG_RESULT" == "failure" ]; then
+            {
+              echo "Failed to generate config from the specified file."
+              echo "Please ensure the file exists and the path is correct."
+              echo "<br>Usage: 'GitHub, generate report by config from <file_path>'"
+              echo "<br>Link: $JOBS_LINK"
+            } > .ci-temp/message
           elif [ -z "$MSG" ]; then
-            API_LINK="https://api.github.com/repos/checkstyle/checkstyle/actions/runs/"
-            API_LINK="${API_LINK}${{github.run_id}}/jobs"
-
+            API_LINK="https://api.github.com/repos/checkstyle/checkstyle/actions/runs/${{github.run_id}}/jobs"
             curl --fail-with-body -X GET "${API_LINK}" \
               -H "Accept: application/vnd.github+json" \
               -H "Authorization: token $GITHUB_TOKEN" \
               -o .ci-temp/info.json
-
             jq '.jobs' .ci-temp/info.json > ".ci-temp/jobs"
             jq '.[] | select(.conclusion == "failure") | .name' .ci-temp/jobs > .ci-temp/job_name
             jq '.[] | select(.conclusion == "failure") | .steps' .ci-temp/jobs > .ci-temp/steps
             jq '.[] | select(.conclusion == "failure") | .name' .ci-temp/steps > .ci-temp/step_name
-            echo "Report generation failed on phase $(cat .ci-temp/job_name)," > .ci-temp/message
-            echo "step $(cat .ci-temp/step_name).<br>Link: $JOBS_LINK" >> .ci-temp/message
+            {
+              echo "Report generation failed on phase $(cat .ci-temp/job_name),"
+              echo "step $(cat .ci-temp/step_name)."
+              echo "<br>Link: $JOBS_LINK"
+            } > .ci-temp/message
           else
             echo "$MSG" > .ci-temp/message
           fi