chore(ci): fix failure condition when modified files are empty

Signed-off-by: Kotaro Yoshimoto <pythagora.yoshimoto@gmail.com>

.github/workflows/cppcheck-differential.yaml

@@ -31,21 +31,20 @@ jobs:
  run: git fetch origin ${{ github.base_ref }}
  shell: bash
 
- - name: Get changed files
- id: changed-files
+ - name: Get modified files
+ id: get-modified-files
  run: |
- git diff --name-only "origin/${{ github.base_ref }}"...HEAD > changed_files.txt
- cat changed_files.txt
+ echo "changed_files=$(git diff --name-only "origin/${{ github.base_ref }}"...HEAD | grep -E '\.(cpp|hpp)$' | tr '\n' ' ' || true)" >> $GITHUB_OUTPUT
  shell: bash
-
+ 
  - name: Run Cppcheck on changed files
  continue-on-error: true
  id: cppcheck
  run: |
  files=$(cat changed_files.txt | grep -E '\.(cpp|hpp)$' || true)
  if [ -n "$files" ]; then
- echo "Running Cppcheck on changed files: $files"
- cppcheck --enable=all --inconclusive --check-level=exhaustive --error-exitcode=1 --suppressions-list=.cppcheck_suppressions $files 2> cppcheck-report.txt
+ echo "Running Cppcheck on changed files: ${{ steps.get-modified-files.outputs.changed_files }}"
+ cppcheck --enable=all --inconclusive --check-level=exhaustive --error-exitcode=1 --suppressions-list=.cppcheck_suppressions ${{ steps.get-modified-files.outputs.changed_files }} 2> cppcheck-report.txt
  else
  echo "No C++ files changed."
  touch cppcheck-report.txt
@@ -63,5 +62,5 @@ jobs:
  path: cppcheck-report.txt
 
  - name: Fail the job if Cppcheck failed
- if: steps.cppcheck.outcome == 'failure'
+ if: ${{ steps.get-modified-files.outputs.changed_files != '' && steps.cppcheck.outcome == 'failure' }}
  run: exit 1