1:M relationship weird behaviour when selecting specific fields explicitely #3012

swapnil-gawali · 2022-04-14T12:10:14Z

swapnil-gawali
Apr 14, 2022

Hello, I am trying to fetch One-to-Many relation. But when we select fields explicitly, it populates relations recursively like User-> Post -> User. It works correctly if I am not selecting any field.

Note: I am using Nestjs.

Config

{
            type: "postgresql",
            dbName: "test",
            user: "test",
            password: "test",
            host: "localhost",
            port: 5432,
            entities: ["dist/**/*.entity.js"],
            entitiesTs: ["src/**/*.entity.ts"],
            debug: true,
            loadStrategy: LoadStrategy.SELECT_IN,
            highlighter: new SqlHighlighter(),
            metadataProvider: TsMorphMetadataProvider,
            registerRequestContext: false,
            migrations: {
                path: "dist/migrations",
                pathTs: "src/migrations",
            },
}

User Entity

@Entity({ tableName: "user", customRepository: () => UserRepository })
export class User {

    [EntityRepositoryType]?: UserRepository;

    @PrimaryKey({ name: "id" })
    id: number;

    @Property({ name: "full_name" })
    fullName: string;

    @OneToMany(() => Post, post => post.user)
    posts = new Collection<Post>(this);
}

Post Entity

@Entity({ tableName: "post", customRepository: () => PostRepository })
export class Post {

    [EntityRepositoryType]?: PostRepository;

    @PrimaryKey({ name: "id" })
    id: number;

    @Property({ name: "bio" })
    bio: string;

    @ManyToOne(() => User)
    user?: User;
}

// find() query to populated 1:M relationship

await this.find({},{ fields: ["id", "fullName", { posts: ["id", "bio", "user"]}], populate: ["posts"] })

// queries generated by Mikro-orm

select "u0"."id", "u0"."full_name" from "user" as "u0"
select "p0"."id", "p0"."bio", "p0"."user_id" from "post" as "p0" where "p0"."user_id" in (1, 2, 3) order by "p0"."user_id" asc

Result

[
    {
        "id": 1,
        "fullName": "hello iii",
        "posts": [
            {
                "id": 1,
                "bio": "hey there its bio",
                "user": { // here is the issue, user object gets re-populated
                    "id": 1, 
                    "fullName": "hello iii"
                }
            }
        ]
    }
]

Expected behavior
The result should not contain user object in posts object.

Versions

Dependency	Version
node	16.13.1
typescript	4.6.3
mikro-orm	5.1.2
your-driver	postgres

B4nan · 2022-04-15T16:26:58Z

B4nan
Apr 15, 2022
Maintainer

Interesting, we recently started inferring populate hints from fields if its not specified explicitly, which for the child entity is not. A bug for sure, sorry for moving to discussions too early :] Got it reproduced, will try to look into it soon.

Minimal repro:

  test('stable results of serialization with partial loading', async () => {
    const god = new Author2('God', 'hello@heaven.god');
    god.books.add(new Book2('Bible', god));
    await orm.em.fork().persistAndFlush(god);

    const newGod = await orm.em.findOneOrFail(Author2, god.id, {
      populate: ['books'],
      fields: [{ books: ['title'] }],
    });
    const json = wrap(newGod).toJSON();
    expect(json.books[0].author).toBe(newGod.id);
  });

2 replies

swapnil-gawali Apr 16, 2022
Author

Thank you

B4nan Apr 17, 2022
Maintainer

Fixed via 00be9f1

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1:M relationship weird behaviour when selecting specific fields explicitely #3012

swapnil-gawali Apr 14, 2022

Replies: 1 comment · 2 replies

B4nan Apr 15, 2022 Maintainer

swapnil-gawali Apr 16, 2022 Author

B4nan Apr 17, 2022 Maintainer

swapnil-gawali
Apr 14, 2022

Replies: 1 comment 2 replies

B4nan
Apr 15, 2022
Maintainer

swapnil-gawali Apr 16, 2022
Author

B4nan Apr 17, 2022
Maintainer