Updating JSON fields with another JSON structure, merges with existing structure instead of replacing the old one

[errol59]

Describe the bug

In the docs the following statement is made:

By default, entity.assign(data) behaves similar to Object.assign(entity, data)...

However, that statement holds not entirely true if you look at my reproduction example.

Reproduction

// table structure: `name` has column type `varchar(255)` and `structure` has column type `jsonb`

const person = new Author('me', { foo: 1, bar: 2  });
// { name: 'me', structure: { foo: 1, bar: 2 } }

wrap(person).assign({ structure: { bar: 3, baz: 4 } });
// Expected: { name: 'me', structure: { bar: 3, baz: 4 } }
// Reality: { name: 'me', structure: { foo: 1, bar: 3, baz: 4 } }

const x = { name: 'me', structure: { foo: 1, bar: 2 } }
console.log(Object.assign(x, { structure: { bar: 3, baz: 4 }}))
// { name: 'me', 'structure': { 'bar': 3, 'baz': 4 } }

What driver are you using?

@mikro-orm/postgresql

MikroORM version

6.1.4

Node.js version

20.10.0

Operating system

Docker WSL

Validations

• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Slack.
• The provided reproduction is a minimal reproducible example of the bug.

[B4nan]

How does your entity look like? There are tests for this behavior, it really does work this way by default - you would need to mergeObjectProperties option for the objects to merge.

Note that this will work only for POJOs, maybe you use a custom class for the data you are assigning?

6.1.4

And be sure to update to latest version first, that should be always your first step when something looks weird.

[B4nan]

I am starting to think that the flag is used for two different things (JSON props and embedded props), and we should in fact have two flags, and only the one for embedded props should be enabled by default.

[errol59]

I am starting to think that the flag is used for two different things (JSON props and embedded props), and we should in fact have two flags, and only the one for embedded props should be enabled by default.

I was thinking the same. The Docs mention embedded props/database relations, but doesn't mention anything regards normal JSON values that can exist inside a single database column.

Also, explicitly setting mergeObjectProperties to false solved my issue.

[B4nan]

The change was introduced here: 7b7c3a2, so the motivation was indeed embedded props.

[B4nan]

I guess I will give this a go, it feels a bit breaking, but since the docs still mention the old default, it feels more like a fix (and the default behavior for JSON props really feels like a bug, I completely agree with that).

[B4nan]

bc9f6f5