I am not sure if it is a bug or just an issue for bad coding practice but I wanted to ask and shared what I found

If you have two entities that are related to each other, let's say Box and Item
In Box, you might import roles to have OneToMany relation

import { Item } from './Item'

@entity()
export class Box {
@onetomany({ entity: () => Item, mappedBy: 'item', orphanRemoval: true })
itemList = new Collection(this)
}

then in Role, if you import User to have the reference, it will introduce a circular import, like this

import { Box } from './Box'

@entity()
export class Item {
@manytoone({ entity: () => 'Box', deleteRule: 'cascade' })
parentBox!: Box
}

In development mode, it works totally fine
When you are managing the element, you can either choose box.itemList.add(newItem) or newItem.parentBox = newBox, both will work perfectly fine. However, if you are running using the built files (I am using containerized version), you will face the error similar to Metadata for entity Box2 not found even when just using em.find(Box, ....)

The entity manager added "2" at the end of the entity for no reason. I suspect that since there are two references for Box, the manager just trace the last one and used that one as the entity name for searching.

My solution is to remove the parentBox in Item entity, just use box.itemList.add(newItem) for binding the relation between Box and Item, that resolve the issue and works perfectly fine for both development and production.

However, I would like to know if it is intended behaviour, is it just not recommended to do so, I am just lucky that development mode works? Since I think some might prefer setting parentBox to bind the relationship, sometimes that might be a clearer solution