Demonstrate issue with loading/unloading record with 1-1 relationships

adapters.bar.js

import DS from 'ember-data';
import RSVP from 'rsvp';

export default DS.RESTAdapter.extend({
	deleteRecord() {
  	const response = this.handleResponse(
      204,
      {},
      {},
      undefined
    );
    
    return RSVP.resolve(response);
  }
});

adapters.foo.js

import DS from 'ember-data';
import RSVP from 'rsvp';

export default DS.RESTAdapter.extend({
	deleteRecord() {
  	const response = this.handleResponse(
      204,
      {},
      {},
      undefined
    );
    
    return RSVP.resolve(response);
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  actions: {
  	destroy(fooModel) {
      const store = this.get('store');
      const bar = fooModel.get('bar');
      
      /**
       * Without this push to null foo data,
       * creating a new bar record with same ID will fail
       */
      store.push({
      	data: {
        	type: 'bar',
          id: bar.get('id'),
          attributes: {},
          relationships: {
          	foo: {
            	data: null
            }
          }
        }
      });

      bar.destroyRecord().then((resp) => {
        console.log(resp);
        
        store.unloadRecord(bar);
      });
    },
    
    pushRecord(fooModel) {
    	const store = this.get('store');
      const bar = store.createRecord('bar', {id: 1});
      
      fooModel.set('bar', bar);
      
      console.log(store.peekRecord('bar', 1));
    }
  }
});

models.bar.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
  foo: belongsTo('foo', {async: false}) 
});

models.foo.js

import Model from 'ember-data/model';
import attr from 'ember-data/attr';
import { belongsTo, hasMany } from 'ember-data/relationships';

export default Model.extend({
  bar: belongsTo('bar', {async: false})
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  
  model() {
  	const store = this.get('store');
    
    store.push({
      data: [{
      	type: 'foo',
        id: 1,
        attributes: {},
        relationships: {
        	bar: {
          	data: {id: 1, type: 'bar'}
          }
        }
      }, {
      	type: 'bar',
        id: 1,
        attributes: {},
        relationships: {
        	foo: {
          	data: {id: 1, type: 'foo'}
          }
        }
      }]
    });
    
    return store.peekRecord('foo', 1);
  }
  
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

foo.bar.id: {{model.bar.id}} <br>

<button {{action "destroy" model}}>Destroy Bar Record from Foo Model</button>
<button {{action "pushRecord" model}}>Push Bar Record</button>

twiddle.json

{
  "version": "0.13.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}