Fix

.github/workflows/checkstyle.yml

@@ -26,11 +26,15 @@ jobs:
     - uses: actions/checkout@v4
       with:
         submodules: true
+
     - name: Set up JDK
       uses: actions/[email protected]
       with:
         java-version: '8'
         distribution: 'adopt'
+
+    - name: Checkout base branch
+      run: git checkout ${{ github.base_ref }}
+
     - name: Run checkstyle
       run: bash ./dev/checkstyle.sh
-

dev/checkstyle.sh

@@ -20,7 +20,7 @@
 set -ex
 
 # Assuming you are in the root of your git repository
-MODIFIED_FILES=$(git diff --name-only HEAD~1)
+MODIFIED_FILES=$(git diff --name-only "${GITHUB_BASE_REF}")
 
 SRC_DIR="src/main/java/"
 TEST_SRC_DIR="src/test/java/"