Circular inclusions can lose data #802
Description
Verified on 0.8.0.beta2 in a simple testing app with three models: Box, Thing, User, where:
boxes ------> things
many | ^
one | |
| | many
v |
users
When requesting
/api/boxes?include=things,things.user
everything looks ok, but when requesting one level deeper for
/api/boxes?include=things,things.user,things.user.things
so that the User includes its Things, some of the thing-to-user relationship data disappears.
It seems that there's a depth-first search that explores the first thing-to-user relationship via the first Thing it encounters and finds the remaining Things through the user-to-things relationship without including the thing-to-user relationship. Requesting
/api/boxes?include=things,things.user,things.user.things,things.user.things.user
with yet another circular reference resolves this, corroborating the depth-first hypothesis.
An example: one Box with two Things, each with the same User. Requests and results of included list (with links and box relationship removed):
# /api/boxes?include=things,things.user
...
{
"id": "1",
"type": "things",
"relationships": {
"user": {
"data": {
"type": "users", "id": "1"
}
}
}
},
{
"id": "2",
"type": "things",
"relationships": {
"user": {
"data": {
"type": "users", "id": "1"
}
}
}
},
{
"id": "1",
"type": "users",
"relationships": {
"things": {}
}
}
...
...
# /api/boxes?include=things,things.user,things.user.things
{
"id": "1",
"type": "things",
"relationships": {
"user": {}
}
},
{
"id": "2",
"type": "things",
"relationships": {
"user": {
"data": {
"type": "users", "id": "1"
}
}
}
},
{
"id": "1",
"type": "users",
"relationships": {
"things": {
"data": [
{
"type": "things", "id": "1"
},
{
"type": "things", "id": "2"
}
]
}
}
}
...
...Thing loses its User data. To get both the things-to-user data and also the user-to-things data, I am having to request:
# /api/boxes?include=things,things.user,things.user.things,things.user.things.user
...
{
"id": "1",
"type": "things",
"relationships": {
"user": {
"data": {
"type": "users", "id": "1"
}
}
}
},
{
"id": "2",
"type": "things",
"relationships": {
"user": {
"data": {
"type": "users", "id": "1"
}
}
}
},
{
"id": "1",
"type": "users",
"relationships": {
"things": {
"data": [
{
"type": "things", "id": "1"
},
{
"type": "things", "id": "2"
}
]
}
}
}
...
My testing app setup:
Rails.application.routes.draw do
namespace :api do
jsonapi_resources :boxes
end
end
class Box < ActiveRecord::Base
has_many :things
end
class Thing < ActiveRecord::Base
belongs_to :box
belongs_to :user
end
class User < ActiveRecord::Base
has_many :things
end
class Api::BoxesController < ApplicationController
include JSONAPI::ActsAsResourceController
end
class Api::BoxResource < JSONAPI::Resource
has_many :things
end
class Api::ThingResource < JSONAPI::Resource
has_one :box
has_one :user
end
class Api::UserResource < JSONAPI::Resource
has_many :things
end