fix: rival apply/#658

src/main/java/com/process/clash/adapter/persistence/rival/rival/RivalJpaRepository.java

@@ -9,6 +9,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 
 

src/main/java/com/process/clash/application/compete/rival/rival/service/ApplyRivalService.java

@@ -2,13 +2,15 @@
 
 import com.process.clash.application.compete.realtime.CompeteRefetchNotifier;
 import com.process.clash.application.compete.rival.rival.data.ApplyRivalData;
+import com.process.clash.application.compete.rival.rival.exception.exception.conflict.AlreadyAppliedRivalException;
 import com.process.clash.application.compete.rival.rival.policy.ApplyRivalPolicy;
 import com.process.clash.application.compete.rival.rival.port.in.ApplyRivalUseCase;
 import com.process.clash.application.compete.rival.rival.port.out.RivalRepositoryPort;
 import com.process.clash.application.user.usernotice.port.out.UserNoticeRepositoryPort;
 import com.process.clash.domain.rival.rival.entity.Rival;
 import com.process.clash.domain.user.usernotice.entity.UserNotice;
 import com.process.clash.domain.user.usernotice.enums.NoticeCategory;
+import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.transaction.annotation.Transactional;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
@@ -35,7 +37,12 @@ public void execute(ApplyRivalData.Command command) {
                 .map(opponentId -> Rival.createDefault(command.actor().id(), opponentId.id()))
                 .toList();
 
-        List<Rival> savedRivals = rivalRepositoryPort.saveAll(rivals);
+        List<Rival> savedRivals;
+        try {
+            savedRivals = rivalRepositoryPort.saveAll(rivals);
+        } catch (DataIntegrityViolationException e) {
+            throw new AlreadyAppliedRivalException();
+        }
 
         List<Long> savedOpponentIds = savedRivals.stream()
                 .map(Rival::secondUserId)

src/main/resources/db/migration/V32__add_unique_index_to_rivals_active_pair.sql

@@ -0,0 +1,63 @@
+-- 레이스 컨디션으로 생성된 중복 PENDING 레코드 정리 후 unique partial index 추가
+--
+-- 제거 대상:
+--   1) 같은 쌍 사이에 PENDING-PENDING 레코드가 2개인 경우 → ID가 큰 것(나중에 생긴 것) 제거
+--   2) 같은 쌍 사이에 이미 ACCEPTED가 존재하는데 PENDING도 남아있는 경우 → PENDING 제거
+--
+-- user_notices.rival_id 는 ON DELETE SET NULL 이므로 rivals 삭제 전에 먼저 직접 삭제해야
+-- orphan notice가 남지 않음
+
+-- Step 1: 제거할 라이벌과 연결된 알림 먼저 삭제
+DELETE FROM user_notices
+WHERE rival_id IN (
+    SELECT r2.id
+    FROM rivals r1
+    JOIN rivals r2
+      ON LEAST(r1.fk_first_user_id, r1.fk_second_user_id)    = LEAST(r2.fk_first_user_id, r2.fk_second_user_id)
+     AND GREATEST(r1.fk_first_user_id, r1.fk_second_user_id) = GREATEST(r2.fk_first_user_id, r2.fk_second_user_id)
+     AND r1.id < r2.id
+     AND r1.rival_linking_status = 'PENDING'
+     AND r2.rival_linking_status = 'PENDING'
+
+    UNION
+
+    SELECT pending.id
+    FROM rivals pending
+    JOIN rivals accepted
+      ON LEAST(pending.fk_first_user_id, pending.fk_second_user_id)    = LEAST(accepted.fk_first_user_id, accepted.fk_second_user_id)
+     AND GREATEST(pending.fk_first_user_id, pending.fk_second_user_id) = GREATEST(accepted.fk_first_user_id, accepted.fk_second_user_id)
+     AND pending.rival_linking_status  = 'PENDING'
+     AND accepted.rival_linking_status = 'ACCEPTED'
+);
+
+-- Step 2: 중복/고아 라이벌 레코드 삭제
+DELETE FROM rivals
+WHERE id IN (
+    SELECT r2.id
+    FROM rivals r1
+    JOIN rivals r2
+      ON LEAST(r1.fk_first_user_id, r1.fk_second_user_id)    = LEAST(r2.fk_first_user_id, r2.fk_second_user_id)
+     AND GREATEST(r1.fk_first_user_id, r1.fk_second_user_id) = GREATEST(r2.fk_first_user_id, r2.fk_second_user_id)
+     AND r1.id < r2.id
+     AND r1.rival_linking_status = 'PENDING'
+     AND r2.rival_linking_status = 'PENDING'
+
+    UNION
+
+    SELECT pending.id
+    FROM rivals pending
+    JOIN rivals accepted
+      ON LEAST(pending.fk_first_user_id, pending.fk_second_user_id)    = LEAST(accepted.fk_first_user_id, accepted.fk_second_user_id)
+     AND GREATEST(pending.fk_first_user_id, pending.fk_second_user_id) = GREATEST(accepted.fk_first_user_id, accepted.fk_second_user_id)
+     AND pending.rival_linking_status  = 'PENDING'
+     AND accepted.rival_linking_status = 'ACCEPTED'
+);
+
+-- Step 3: 동일 유저 쌍에 대해 PENDING/ACCEPTED 상태의 레코드가 중복 생성되는 것을 방지
+-- LEAST/GREATEST로 방향(firstUser/secondUser)과 무관하게 정규화
+CREATE UNIQUE INDEX uq_rivals_active_pair
+ON rivals (
+    LEAST(fk_first_user_id, fk_second_user_id),
+    GREATEST(fk_first_user_id, fk_second_user_id)
+)
+WHERE rival_linking_status IN ('PENDING', 'ACCEPTED');