Update include-what-you-use.yml

.github/workflows/include-what-you-use.yml

@@ -22,8 +22,13 @@ jobs:
       run: set -o pipefail; iwyu_tool -j 4 -p build -- -Xiwyu --no_default_mapping -Xiwyu --mapping_file=$PWD/include-what-you-use.imp | tee build/build-log.txt
     - name: Apply include-what-you-use recommendations
       run: fix_include --nosafe_headers --ignore_re '/lib/' < build/build-log.txt
+    - name: Check if any files were changed
+      run: git diff --quiet && echo "has_diff=true" || echo "has_diff=false" >> "$GITHUB_OUTPUT"
+      id: has_diff
     - run: git diff > build/include-what-you-use-diff.txt
+      if: steps.has_diff.outputs.has_diff
     - name: Upload the diff
+      if: steps.has_diff.outputs.has_diff
       uses: actions/upload-artifact@v4
       with:
         name: include-what-you-use-diff