refactor(auth): null처리 수정

src/main/java/com/project/bumawiki/domain/auth/service/CommandAuthService.java

@@ -28,10 +28,10 @@ public class CommandAuthService {
 
 	public Token login(String authId) {
 		User unknownUser = bsmLoginHandler.getUserByAuthId(authId);
-		User user = userReader.getByEmail(unknownUser.getEmail());
+		User user = userReader.getNullableUserByEmail(unknownUser.getEmail());
 
 		if (user == null) {
-			userCreator.create(unknownUser);
+			user = userCreator.create(unknownUser);
 		} else {
 			userUpdater.update(user, unknownUser);
 		}

src/main/java/com/project/bumawiki/domain/user/domain/repository/UserRepository.java

@@ -1,11 +1,9 @@
 package com.project.bumawiki.domain.user.domain.repository;
 
-import java.util.Optional;
-
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import com.project.bumawiki.domain.user.domain.User;
 
 public interface UserRepository extends JpaRepository<User, Long> {
-	Optional<User> findByEmail(String email);
+	User findByEmail(String email);
 }

src/main/java/com/project/bumawiki/domain/user/implementation/UserCreator.java

@@ -11,7 +11,7 @@
 public class UserCreator {
 	private final UserRepository userRepository;
 
-	public void create(User user) {
-		userRepository.save(user);
+	public User create(User user) {
+		return userRepository.save(user);
 	}
 }

src/main/java/com/project/bumawiki/domain/user/implementation/UserReader.java

@@ -17,7 +17,7 @@ public User getById(Long id) {
 		return userRepository.findById(id).orElseThrow(() -> new BumawikiException(ErrorCode.USER_NOT_FOUND));
 	}
 
-	public User getByEmail(String email) {
-		return userRepository.findByEmail(email).orElseThrow(() -> new BumawikiException(ErrorCode.USER_NOT_FOUND));
+	public User getNullableUserByEmail(String email) {
+		return userRepository.findByEmail(email);
 	}
 }