fix(library): keep backlog edits made during a sync, reject fractional ratings

UserGame now uses @DynamicUpdate, so the sync flush writes only the columns it
changed and no longer overwrites a backlog update committed meanwhile.

src/main/java/core_service/modules/library/domain/UserGame.java

@@ -11,10 +11,13 @@ import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
+import org.hibernate.annotations.DynamicUpdate;
 
 import java.time.Instant;
 
 @Entity
+// The sync and the backlog update run in separate transactions on the same row; each must write only its own columns.
+@DynamicUpdate
 @Table(name = "user_game")
 @IdClass(UserGameId.class)
 @Getter

src/main/resources/application.yml

@@ -3,6 +3,9 @@ spring:
     name: tbp-core-service
   profiles:
     active: prod
+  jackson:
+    deserialization:
+      accept-float-as-int: false
   jpa:
     open-in-view: true
   flyway:

src/test/java/core_service/modules/library/api/LibraryControllerBacklogTest.java

@@ -100,6 +100,15 @@ class LibraryControllerBacklogTest extends AbstractIntegrationTest {
         assertEquals(GameStatus.BACKLOG, stored().getStatus());
     }
 
+    @Test
+    void updateBacklog_FractionalRating_Is400() throws Exception {
+        mockMvc.perform(put("/api/library/games/220/backlog").contentType(MediaType.APPLICATION_JSON)
+                        .content("{\"status\":\"PLAYING\",\"rating\":4.7}"))
+                .andExpect(status().isBadRequest());
+
+        assertNull(stored().getRating());
+    }
+
     @Test
     void updateBacklog_NotesTooLong_Is400() throws Exception {
         String notes = "x".repeat(2001);

src/test/java/core_service/modules/library/repo/UserGameRepositoryTest.java

@@ -10,6 +10,11 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Sort;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.TransactionDefinition;
+import org.springframework.transaction.annotation.Propagation;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.support.TransactionTemplate;
 
 import java.time.Instant;
 import java.util.List;
@@ -28,6 +33,9 @@ class UserGameRepositoryTest extends AbstractPersistenceTest {
     @Autowired
     private SteamGameRepository steamGameRepository;
 
+    @Autowired
+    private PlatformTransactionManager transactionManager;
+
     @BeforeEach
     void seed() {
         steamGameRepository.saveAll(List.of(
@@ -89,4 +97,38 @@ class UserGameRepositoryTest extends AbstractPersistenceTest {
         assertNull(UserGameRepository.containsPattern("  "));
         assertNull(UserGameRepository.containsPattern(null));
     }
+
+    @Test
+    @Transactional(propagation = Propagation.NOT_SUPPORTED)
+    void syncFlushKeepsBacklogEditCommittedMeanwhile() {
+        UserGameId id = new UserGameId(USER_ID, 220L);
+        TransactionTemplate syncTx = new TransactionTemplate(transactionManager);
+        TransactionTemplate userTx = new TransactionTemplate(transactionManager);
+        userTx.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRES_NEW);
+        try {
+            syncTx.executeWithoutResult(sync -> {
+                // LibrarySyncWorker.upsertUserGame: entity loaded with status PLAYING (300 min playtime)
+                UserGame syncView = userGameRepository.findById(id).orElseThrow();
+
+                // BacklogService.update commits in its own transaction while the sync is still running
+                userTx.executeWithoutResult(user -> {
+                    UserGame edit = userGameRepository.findById(id).orElseThrow();
+                    edit.setStatus(GameStatus.FINISHED);
+                    edit.setRating(5);
+                });
+
+                // the sync only touches playtime and lastSeenAt, then commits
+                syncView.setPlaytimeMinutes(400);
+                syncView.setLastSeenAt(Instant.now());
+            });
+
+            UserGame stored = userGameRepository.findById(id).orElseThrow();
+            assertEquals(400, stored.getPlaytimeMinutes());
+            assertEquals(GameStatus.FINISHED, stored.getStatus());
+            assertEquals(5, stored.getRating());
+        } finally {
+            userGameRepository.deleteAll();
+            steamGameRepository.deleteAll();
+        }
+    }
 }