Create Model with relations overwrites foreignKey

[primissus]

Bug or feature request

• Bug
• Feature request

Steps to reproduce

Having two models:

ModelA

{
  "name": "ModelA",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {},
  "validations": [],
  "relations": {},
  "acls": [],
  "methods": {}
}

and ModelB

{
  "name": "ModelB",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {},
  "validations": [],
  "relations": {
    "modelA": {
      "type": "belongsTo",
      "model": "ModelA",
      "foreignKey": "modelaId"
    }
  },
  "acls": [],
  "methods": {}
}

Notice that ModelBhas a belongsTo relation with ModelA.

1. Create one ModelA

{
    "_id" : ObjectId("5ca3b7a61076971a4308c4ce")
}

2. Create one ModelB just setting modelaId

{
  "modelaId": "5ca3b7a61076971a4308c4ce",
}

result will include ObjectId which I consider is correct:

{
    "_id" : ObjectId("5ca3b7f81076971a4308c4cf"),
    "modelaId" : ObjectId("5ca3b7a61076971a4308c4ce")
}

3. Create another ModelB but this time including modelA related model.

{
    "modelaId": "5ca3b7a61076971a4308c4ce",
    "modelA": {
    	"id": "5ca3b7a61076971a4308c4ce"
	}
}

the result will have modelaId as string wich will have the query filter issue from #3593

Link to reproduction sandbox

https://github.com/primissus/loopback-relation-bug-sandbox/blob/master/README.md

Expected result

Both methods should result in a model including ObjectId properties.

Additional information

darwin x64 11.4.0

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[primissus]

While debugging I found that the change of value occurs at loopback-datasource-juggler/lib/model.js:226

I undestand that model's foreign key is obtained from relation id, but I think it should check if should be converted to ObjectId.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been closed due to continued inactivity. Thank you for your understanding. If you believe this to be in error, please contact one of the code owners, listed in the CODEOWNERS file at the top-level of this repository.