fix(core): merge returned values to the initial entity snapshot

Closes #4284

packages/core/src/EntityManager.ts

@@ -628,7 +628,7 @@ export class EntityManager<D extends IDatabaseDriver = IDatabaseDriver> {
       convertCustomTypes: true,
     });
 
-    em.unitOfWork.getChangeSetPersister().mapReturnedValues(entity, ret.row, meta);
+    em.unitOfWork.getChangeSetPersister().mapReturnedValues(entity, data, ret.row, meta);
 
     if (!helper(entity).hasPrimaryKey()) {
       const pk = await this.driver.findOne(meta.className, where, {
@@ -771,7 +771,7 @@ export class EntityManager<D extends IDatabaseDriver = IDatabaseDriver> {
         convertCustomTypes: true,
       });
 
-      em.unitOfWork.getChangeSetPersister().mapReturnedValues(entity, ret.rows?.[i], meta);
+      em.unitOfWork.getChangeSetPersister().mapReturnedValues(entity, data![i], ret.rows?.[i], meta);
 
       if (!helper(entity).hasPrimaryKey()) {
         loadPK.set(entity, allWhere[i]);

packages/core/src/unit-of-work/ChangeSetPersister.ts

@@ -1,5 +1,5 @@
 import type { MetadataStorage } from '../metadata';
-import type { AnyEntity, Dictionary, EntityData, EntityMetadata, EntityProperty, FilterQuery, IHydrator, IPrimaryKey } from '../typings';
+import type { AnyEntity, Dictionary, EntityData, EntityDictionary, EntityMetadata, EntityProperty, FilterQuery, IHydrator, IPrimaryKey } from '../typings';
 import type { EntityFactory, EntityValidator, Collection } from '../entity';
 import { EntityIdentifier, helper } from '../entity';
 import type { ChangeSet } from './ChangeSet';
@@ -110,7 +110,7 @@ export class ChangeSetPersister {
       this.mapPrimaryKey(meta, res.insertId as number, changeSet);
     }
 
-    this.mapReturnedValues(changeSet.entity, res.row, meta);
+    this.mapReturnedValues(changeSet.entity, changeSet.payload, res.row, meta);
     this.markAsPopulated(changeSet, meta);
     wrapped.__initialized = true;
     wrapped.__managed = true;
@@ -159,7 +159,7 @@ export class ChangeSetPersister {
         this.mapPrimaryKey(meta, res.rows![i][field], changeSet);
       }
 
-      this.mapReturnedValues(changeSet.entity, res.rows![i], meta);
+      this.mapReturnedValues(changeSet.entity, changeSet.payload, res.rows![i], meta);
       this.markAsPopulated(changeSet, meta);
       wrapped.__initialized = true;
       wrapped.__managed = true;
@@ -381,7 +381,7 @@ export class ChangeSetPersister {
    * No need to handle composite keys here as they need to be set upfront.
    * We do need to map to the change set payload too, as it will be used in the originalEntityData for new entities.
    */
-  mapReturnedValues<T extends object>(entity: T, row: Dictionary | undefined, meta: EntityMetadata<T>): void {
+  mapReturnedValues<T extends object>(entity: T, payload: EntityDictionary<T>, row: Dictionary | undefined, meta: EntityMetadata<T>): void {
     if (this.platform.usesReturningStatement() && row && Utils.hasObjectKeys(row)) {
       const data = meta.props.reduce((ret, prop) => {
         if (prop.fieldNames && row[prop.fieldNames[0]] != null && entity[prop.name] == null) {
@@ -393,6 +393,7 @@ export class ChangeSetPersister {
 
       if (Utils.hasObjectKeys(data)) {
         this.hydrator.hydrate(entity, meta, data as EntityData<T>, this.factory, 'returning', false, true);
+        Object.assign(payload, data); // merge to the changeset payload, so it gets saved to the entity snapshot
       }
     }
   }

tests/features/unit-of-work/GH4284.test.ts

@@ -0,0 +1,41 @@
+import { Entity, OptionalProps, PrimaryKey, Property, SimpleLogger } from '@mikro-orm/core';
+import { MikroORM } from '@mikro-orm/sqlite';
+import { mockLogger } from '../../helpers';
+
+@Entity()
+class AEntity {
+
+  [OptionalProps]?: 'name';
+
+  @PrimaryKey()
+  id!: string;
+
+  @Property({ default: 'value1' })
+  name!: string;
+
+}
+
+let orm: MikroORM;
+
+beforeAll(async () => {
+  orm = await MikroORM.init({
+    dbName: ':memory:',
+    entities: [AEntity],
+    loggerFactory: options => new SimpleLogger(options),
+  });
+  await orm.schema.createSchema();
+});
+
+afterAll(() => orm.close(true));
+
+test(`GH issue 4284`, async () => {
+  orm.em.create(AEntity, { id: '1' });
+  const mock = mockLogger(orm);
+  await orm.em.flush();
+  await orm.em.flush();
+  expect(mock.mock.calls).toEqual([
+    ['[query] begin'],
+    ['[query] insert into `aentity` (`id`) values (\'1\') returning `id`, `name`'],
+    ['[query] commit'],
+  ]);
+});