fix(core): fix populating references for 1:m collections

Closes #5336

packages/knex/src/AbstractSqlDriver.ts

@@ -1055,7 +1055,7 @@ export abstract class AbstractSqlDriver<Connection extends AbstractSqlConnection
             continue;
           }
 
-          if (prop.kind === ReferenceKind.MANY_TO_MANY && ref) {
+          if ([ReferenceKind.ONE_TO_MANY, ReferenceKind.MANY_TO_MANY].includes(prop.kind) && ref) {
             map[pk][propName] = [...map[pk][propName], ...(item[propName] as T[])];
             continue;
           }

tests/features/collection/GH5336.test.ts

@@ -0,0 +1,58 @@
+import { Collection, ManyToOne, OneToMany, Entity, MikroORM, PrimaryKey, Property } from '@mikro-orm/sqlite';
+
+@Entity()
+class User {
+
+  @PrimaryKey()
+  id!: number;
+
+  @Property()
+  name!: string;
+
+  @Property({ unique: true })
+  email!: string;
+
+  @OneToMany({ entity: () => Book, mappedBy: 'author' })
+  books = new Collection<Book>(this);
+
+}
+
+@Entity()
+class Book {
+
+  @PrimaryKey()
+  id!: number;
+
+  @Property()
+  name!: string;
+
+  @ManyToOne({ entity: () => User })
+  author!: User;
+
+}
+
+let orm: MikroORM;
+
+beforeAll(async () => {
+  orm = await MikroORM.init({
+    dbName: ':memory:',
+    entities: [User, Book],
+  });
+  await orm.schema.refreshDatabase();
+});
+
+afterAll(async () => {
+  await orm.close(true);
+});
+
+test('5336', async () => {
+  const author = orm.em.create(User, { name: 'Foo', email: 'foo' });
+  orm.em.create(Book, { name: 'Foo1', author });
+  orm.em.create(Book, { name: 'Foo2', author });
+  await orm.em.flush();
+
+  const user2 = await orm.em.fork().findOneOrFail(User, { name: 'Foo' }, { populate: ['books:ref'] });
+  const user1 = await orm.em.fork().findOneOrFail(User, { name: 'Foo' }, { populate: ['books'] });
+  expect(user1.books).toHaveLength(2);
+  expect(user2.books).toHaveLength(2);
+});