backend/src/main/java/org/raddatz/familienarchiv/service/PersonMentionPropagationListener.java

@@ -61,7 +61,7 @@ public class PersonMentionPropagationListener {
             }
         }
 
-        blockRepository.saveAll(blocks);
+        blockRepository.saveAllAndFlush(blocks);
 
         log.info("Propagated rename {} → {} across {} block(s) for person {}",
                 event.oldDisplayName(), event.newDisplayName(), blocks.size(), event.personId());

backend/src/main/java/org/raddatz/familienarchiv/service/PersonService.java

@@ -20,6 +20,7 @@ import org.raddatz.familienarchiv.model.PersonType;
 import org.raddatz.familienarchiv.repository.PersonNameAliasRepository;
 import org.raddatz.familienarchiv.repository.PersonRepository;
 import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.dao.OptimisticLockingFailureException;
 import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
@@ -176,7 +177,12 @@ public class PersonService {
         Person saved = personRepository.save(person);
         String newDisplayName = saved.getDisplayName();
         if (!Objects.equals(oldDisplayName, newDisplayName)) {
-            eventPublisher.publishEvent(new PersonDisplayNameChangedEvent(id, oldDisplayName, newDisplayName));
+            try {
+                eventPublisher.publishEvent(new PersonDisplayNameChangedEvent(id, oldDisplayName, newDisplayName));
+            } catch (OptimisticLockingFailureException e) {
+                throw DomainException.conflict(ErrorCode.PERSON_RENAME_CONFLICT,
+                        "A referenced transcription block was modified concurrently — rename rolled back");
+            }
         }
         return saved;
     }

backend/src/test/java/org/raddatz/familienarchiv/service/PersonServiceTest.java

@@ -10,6 +10,7 @@ import org.raddatz.familienarchiv.dto.PersonNameAliasDTO;
 import org.raddatz.familienarchiv.dto.PersonSummaryDTO;
 import org.raddatz.familienarchiv.dto.PersonUpdateDTO;
 import org.raddatz.familienarchiv.exception.DomainException;
+import org.raddatz.familienarchiv.exception.ErrorCode;
 import org.raddatz.familienarchiv.model.Person;
 import org.raddatz.familienarchiv.model.PersonDisplayNameChangedEvent;
 import org.raddatz.familienarchiv.model.PersonNameAlias;
@@ -18,6 +19,7 @@ import org.raddatz.familienarchiv.model.PersonType;
 import org.raddatz.familienarchiv.repository.PersonNameAliasRepository;
 import org.raddatz.familienarchiv.repository.PersonRepository;
 import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.dao.OptimisticLockingFailureException;
 import org.springframework.web.server.ResponseStatusException;
 
 import java.util.List;
@@ -297,6 +299,28 @@ class PersonServiceTest {
         verify(eventPublisher, never()).publishEvent(any(PersonDisplayNameChangedEvent.class));
     }
 
+    @Test
+    void updatePerson_throwsConflict_whenListenerSignalsOptimisticLockFailure() {
+        UUID id = UUID.randomUUID();
+        Person existing = Person.builder()
+                .id(id).firstName("Auguste").lastName("Raddatz")
+                .personType(PersonType.PERSON).build();
+
+        when(personRepository.findById(id)).thenReturn(Optional.of(existing));
+        when(personRepository.save(any())).thenAnswer(inv -> inv.getArgument(0));
+        doThrow(new OptimisticLockingFailureException("simulated concurrent block save"))
+                .when(eventPublisher).publishEvent(any(PersonDisplayNameChangedEvent.class));
+
+        PersonUpdateDTO dto = new PersonUpdateDTO();
+        dto.setPersonType(PersonType.PERSON);
+        dto.setFirstName("Augusta"); dto.setLastName("Raddatz");
+
+        assertThatThrownBy(() -> personService.updatePerson(id, dto))
+                .isInstanceOf(DomainException.class)
+                .matches(e -> ((DomainException) e).getCode() == ErrorCode.PERSON_RENAME_CONFLICT)
+                .matches(e -> ((DomainException) e).getStatus().value() == 409);
+    }
+
     @Test
     void updatePerson_doesNotPublishEvent_whenOnlyNotesChanges() {
         UUID id = UUID.randomUUID();