fix: 안드로이드 앱 버전 null 체크

Author: yuseok0215

src/main/java/bitnagil/bitnagil_backend/appVersion/Repository/AndroidAppVersionRepository.java

@@ -1,11 +1,13 @@
 package bitnagil.bitnagil_backend.appVersion.Repository;
 
+import java.util.Optional;
+
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import bitnagil.bitnagil_backend.appVersion.domain.AndroidAppVersion;
 
 public interface AndroidAppVersionRepository extends JpaRepository<AndroidAppVersion, Long> {
 
     // major, minor가 가장 높은 AndroidAppVersion을 조회
-    AndroidAppVersion findFirstByOrderByMajorDescMinorDesc();
+    Optional<AndroidAppVersion> findFirstByOrderByMajorDescMinorDesc();
 }

src/main/java/bitnagil/bitnagil_backend/appVersion/service/AndroidAppVersionService.java

@@ -6,6 +6,8 @@
 import bitnagil.bitnagil_backend.appVersion.Repository.AndroidAppVersionRepository;
 import bitnagil.bitnagil_backend.appVersion.domain.AndroidAppVersion;
 import bitnagil.bitnagil_backend.appVersion.response.ForceUpdateResponse;
+import bitnagil.bitnagil_backend.global.errorcode.ErrorCode;
+import bitnagil.bitnagil_backend.global.exception.CustomException;
 import lombok.RequiredArgsConstructor;
 
 @Service
@@ -17,7 +19,8 @@ public class AndroidAppVersionService {
     @Transactional(readOnly = true)
     public ForceUpdateResponse validateForceUpdateRequired(Integer clientMajor, Integer clientMinor) {
 
-        AndroidAppVersion latestVersion = androidAppVersionRepository.findFirstByOrderByMajorDescMinorDesc();
+        AndroidAppVersion latestVersion = androidAppVersionRepository.findFirstByOrderByMajorDescMinorDesc()
+            .orElseThrow(() -> new CustomException(ErrorCode.NOT_FOUND_ANDROID_APP_VERSION));
 
         // major 비교
         if (clientMajor < latestVersion.getMajor()) {

src/main/java/bitnagil/bitnagil_backend/global/errorcode/ErrorCode.java

@@ -87,7 +87,10 @@ public enum ErrorCode {
     JSON_PARSE_ERROR("ETC001", HttpStatus.INTERNAL_SERVER_ERROR, "JSON 문자열을 List<String> 으로 변환하는 데 실패했습니다."),
 
     // 제보 관련 에러코드
-    NOT_FOUND_REPORT("RP001", HttpStatus.NOT_FOUND, "존재하지 않는 제보입니다.");
+    NOT_FOUND_REPORT("RP001", HttpStatus.NOT_FOUND, "존재하지 않는 제보입니다."),
+
+    // 안드로이드 버전 관련 에러코드
+    NOT_FOUND_ANDROID_APP_VERSION("AAV001", HttpStatus.NOT_FOUND, "안드로이드 앱 버전을 찾을 수 없습니다.");