fix(core): fix updating complex composite key entities via UoW (#4739)

Closes #4720

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

@@ -29,7 +29,15 @@ export class ChangeSet<T> {
 
     if (object && this.primaryKey != null) {
       const pks = this.meta.compositePK && Utils.isPlainObject(this.primaryKey) ? Object.values(this.primaryKey) : Utils.asArray(this.primaryKey);
+      const pkProps = this.meta.getPrimaryProps();
       const ret = this.meta.primaryKeys.reduce((o, pk, idx) => {
+        const pkProp = pkProps[idx];
+
+        if (Utils.isPlainObject(pks[idx]) && pkProp.targetMeta) {
+          o[pk] = Utils.getOrderedPrimaryKeys(pks[idx], pkProp.targetMeta) as any;
+          return o;
+        }
+
         o[pk] = pks[idx] as any;
         return o;
       }, {} as T);

tests/issues/GH4720.test.ts

@@ -0,0 +1,109 @@
+import {
+  Collection,
+  Entity,
+  LoadStrategy,
+  ManyToOne,
+  OneToMany,
+  PrimaryKey,
+  PrimaryKeyProp,
+  PrimaryKeyType,
+  Property,
+  Unique,
+} from '@mikro-orm/core';
+import { MikroORM } from '@mikro-orm/postgresql';
+
+@Entity()
+class Parent {
+
+  @PrimaryKey()
+  id!: number;
+
+  @Property()
+  @Unique()
+  uniqueProp!: string;
+
+  @OneToMany({ entity: () => Child, mappedBy: 'parent' })
+  children: Collection<Child> = new Collection<Child>(this);
+
+  @Property()
+  data!: string;
+
+}
+@Entity()
+class ChildType {
+
+  [PrimaryKeyProp]?: 'foo' | 'boo';
+  [PrimaryKeyType]?: [string, string];
+
+  @PrimaryKey()
+  foo!: string;
+
+  @PrimaryKey()
+  boo!: string;
+
+  @Property()
+  data!: string;
+
+}
+
+@Entity()
+class Child {
+
+  [PrimaryKeyProp]?: 'parent' | 'type';
+  [PrimaryKeyType]?: [number, [string, string]];
+
+  @ManyToOne({ entity: () => Parent, primary: true })
+  parent!: Parent;
+
+  @ManyToOne({ entity: () => ChildType, primary: true })
+  type!: ChildType;
+
+  @Property()
+  data!: string;
+
+}
+
+let orm: MikroORM;
+
+beforeAll(async () => {
+  orm = await MikroORM.init({
+    entities: [Parent],
+    dbName: '4720',
+    loadStrategy: LoadStrategy.JOINED,
+  });
+  await orm.schema.refreshDatabase();
+});
+
+afterAll(() => orm.close(true));
+
+test('GH 4720', async () => {
+  const parent = await orm.em.insert(Parent, {
+    uniqueProp: 'aaa',
+    data: '123',
+  });
+  await orm.em.insertMany(ChildType, [
+    { foo: 'f1', boo: 'b1', data: '456' },
+    { foo: 'f2', boo: 'b2', data: '789' },
+  ]);
+  await orm.em.insertMany(Child, [
+    { parent, type: ['f1', 'b1'], data: '111' },
+    { parent, type: ['f2', 'b2'], data: '222' },
+  ]);
+
+  const p = await orm.em.findOneOrFail(Parent, {
+    uniqueProp: 'aaa',
+  });
+
+  p.data = 'pppppppppp';
+  await orm.em.flush();
+
+  const sameParent = await orm.em.findOneOrFail(
+    Parent,
+    { uniqueProp: 'aaa' },
+    { populate: ['children', 'children.type'] },
+  );
+
+  sameParent.children[0].data = 'eeeeeeeeeee';
+  sameParent.children[1].data = 'wwwwwwwwwww';
+  await orm.em.flush();
+});