DATAGRAPH-413: ConcurrentModificationException occurs when trying to persist entity after modification outside of transaction

spring-data-neo4j-aspects/src/test/java/org/springframework/data/neo4j/aspects/support/ModificationOutsideOfTransactionTests.java

@@ -178,6 +178,27 @@ public class ModificationOutsideOfTransactionTests extends EntityTestBase {
         }
     }
 
+    @Test
+    public void testSetPropertyOutsideTransactionCanBePersistedThereafter()
+    {
+        Person p = persistedPerson( "Michael", 35 );
+        p.setAge( 25 );
+        assertEquals(25, p.getAge());
+
+        try (Transaction tx = neo4jTemplate.getGraphDatabase().beginTx()) {
+            assertEquals( 35, nodeFor( p ).getProperty("age") );
+            tx.success();
+        }
+
+        p.persist();
+
+        try (Transaction tx = neo4jTemplate.getGraphDatabase().beginTx()) {
+            assertEquals( 25, nodeFor( p ).getProperty("age") );
+            tx.success();
+        }
+
+    }
+
     @Test
     public void shouldWorkWithUninitializedCollectionFieldWithoutUnderlyingState() {
         Group group = new Group();

spring-data-neo4j/src/main/java/org/springframework/data/neo4j/fieldaccess/DetachedEntityState.java

@@ -159,6 +159,15 @@ public class DetachedEntityState<STATE> implements EntityState<STATE> {
                     Object valueFromDb = null;
                     if (template.transactionIsRunning()) {
                         valueFromDb = unwrap(delegate.getValue(property, MappingPolicy.MAP_FIELD_DIRECT_POLICY));
+                    } else {
+                        // For Implicit Transactions, we need to create
+                        // a tx to ensure we get the correct previous value
+                        // otherwise the possibility of getting a concurrent
+                        // modification exception when next persisting may occur
+                        try (Transaction tx = template.getGraphDatabaseService().beginTx()) {
+                            valueFromDb = unwrap(delegate.getValue(property, MappingPolicy.MAP_FIELD_DIRECT_POLICY));
+                            tx.success();
+                        }
                     }
                     addDirty(property, valueFromDb, true);
                 }