From b3e1d67899b06b051a0cc2c12635998215ad6621 Mon Sep 17 00:00:00 2001
From: Stefan Penner <stefan.penner@gmail.com>
Date: Fri, 11 Nov 2016 12:54:57 -0800
Subject: [PATCH] [BUGFIX #4649 #4648]
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* no longer invalid relationships property when accessing it the first time #4649
* no longer duplicate  “notifyHasManyChange” when adding a record fixes #4648

No longer warn/error in glimmer 2 by accidentally causing duplicate work.
---
 addon/-private/system/many-array.js             | 15 +++++++--------
 tests/unit/model/relationships/has-many-test.js | 17 ++++++++++++++++-
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/addon/-private/system/many-array.js b/addon/-private/system/many-array.js
index 8501010f9df..a79d590ee24 100644
--- a/addon/-private/system/many-array.js
+++ b/addon/-private/system/many-array.js
@@ -129,7 +129,7 @@ export default Ember.Object.extend(Ember.MutableArray, Ember.Evented, {
     this.relationship = this.relationship || null;
 
     this.currentState = Ember.A([]);
-    this.flushCanonical();
+    this.flushCanonical(false);
   },
 
   objectAt(index) {
@@ -141,7 +141,7 @@ export default Ember.Object.extend(Ember.MutableArray, Ember.Evented, {
     return this.currentState[index].getRecord();
   },
 
-  flushCanonical() {
+  flushCanonical(isInitialized = true) {
     let toSet = this.canonicalState;
 
     //a hack for not removing new records
@@ -161,8 +161,11 @@ export default Ember.Object.extend(Ember.MutableArray, Ember.Evented, {
     }
     this.currentState = toSet;
     this.arrayContentDidChange(0, oldLength, this.length);
-    //TODO Figure out to notify only on additions and maybe only if unloaded
-    this.relationship.notifyHasManyChanged();
+
+    if (isInitialized) {
+      //TODO Figure out to notify only on additions and maybe only if unloaded
+      this.relationship.notifyHasManyChanged();
+    }
   },
 
   internalReplace(idx, amt, objects) {
@@ -173,10 +176,6 @@ export default Ember.Object.extend(Ember.MutableArray, Ember.Evented, {
     this.currentState.splice.apply(this.currentState, [idx, amt].concat(objects));
     this.set('length', this.currentState.length);
     this.arrayContentDidChange(idx, amt, objects.length);
-    if (objects) {
-      //TODO(Igor) probably needed only for unloaded records
-      this.relationship.notifyHasManyChanged();
-    }
   },
 
   //TODO(Igor) optimize
diff --git a/tests/unit/model/relationships/has-many-test.js b/tests/unit/model/relationships/has-many-test.js
index db8d92ebb34..57bf2f9dabb 100644
--- a/tests/unit/model/relationships/has-many-test.js
+++ b/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) {