[BUGFIX] Quick Hack: lazyRelationships should not emit change events …

…on first access

This is to confirm this is the only issue we have seen upgrading. We should clean this up more, initial access to this collection should likely take a much simpler code-path.

addon/-private/system/relationships/has-many.js

@@ -164,8 +164,11 @@ export const HasManyMixin = Ember.Mixin.create({
     //We need to notifyPropertyChange in the adding case because we need to make sure
     //we fetch the newly added record in case it is unloaded
     //TODO(Igor): Consider whether we could do this only if the record state is unloaded
-
     //Goes away once hasMany is double promisified
-    this.notifyPropertyChange(key);
+    //
+    let cache = Ember.meta(this).readableCache();
+    if (typeof cache === 'object' && cache !== null && cache[key] !== undefined) {
+      this.notifyPropertyChange(key);
+    }
   }
 });

tests/unit/model/relationships/has-many-test.js

@@ -770,9 +770,13 @@ test("DS.hasMany is async by default", function(assert) {
 });
 
 test("DS.ManyArray is lazy", function(assert) {
+  let peopleDidChange = 0;
   let Tag = DS.Model.extend({
     name: DS.attr('string'),
-    people: DS.hasMany('person')
+    people: DS.hasMany('person'),
+    peopleDidChange: Ember.observer('people', function() {
+      peopleDidChange++;
+    })
   });
 
   let Person = DS.Model.extend({
@@ -787,9 +791,20 @@ test("DS.ManyArray is lazy", function(assert) {
   let hasManyRelationship = tag.hasMany('people').hasManyRelationship;
   assert.ok(!hasManyRelationship._manyArray);
   run(function() {
+    assert.equal(peopleDidChange, 0, 'expect people hasMany to not emit a change event (before access)');
     tag.get('people');
+    assert.equal(peopleDidChange, 0, 'expect people hasMany to not emit a change event (sync after access)');
   });
+  assert.equal(peopleDidChange, 0, 'expect people hasMany to not emit a change event (after access, but after the current run loop)');
   assert.ok(hasManyRelationship._manyArray instanceof DS.ManyArray);
+
+  let person = Ember.run(() => env.store.createRecord('person'));
+
+  Ember.run(() => {
+    assert.equal(peopleDidChange, 0, 'expect people hasMany to not emit a change event (before access)');
+    tag.get('people').addObject(person);
+    assert.equal(peopleDidChange, 1, 'expect people hasMany to have changed exactly once');
+  });
 });
 
 testInDebug("throws assertion if of not set with an array", function(assert) {