Don't notify relationships with links during initialization

addon/-private/system/relationships/state/relationship.js

@@ -346,7 +346,7 @@ export default class Relationship {
     this.store._updateRelationshipState(this);
   }
 
-  updateLink(link) {
+  updateLink(link, initial) {
     heimdall.increment(updateLink);
     warn(`You pushed a record of type '${this.internalModel.modelName}' with a relationship '${this.key}' configured as 'async: false'. You've included a link but no primary data, this may be an error in your payload.`, this.isAsync || this.hasData , {
       id: 'ds.store.push-link-for-sync-relationship'
@@ -355,7 +355,10 @@ export default class Relationship {
 
     this.link = link;
     this.linkPromise = null;
-    this.internalModel.notifyPropertyChange(this.key);
+
+    if (!initial) {
+      this.internalModel.notifyPropertyChange(this.key);
+    }
   }
 
   findLink() {

addon/-private/system/store.js

@@ -2873,7 +2873,7 @@ function setupRelationships(store, internalModel, data, modelNameToInverseMap) {
 
     if (relationshipRequiresNotification) {
       let relationshipData = data.relationships[relationshipName];
-      relationships.get(relationshipName).push(relationshipData);
+      relationships.get(relationshipName).push(relationshipData, false);
     }
 
     // in debug, assert payload validity eagerly

tests/integration/relationships/belongs-to-test.js

@@ -1500,3 +1500,38 @@ testInDebug("A belongsTo relationship warns if malformatted data is pushed into
     });
   }, /expected the data for the book relationship on a <chapter:1> to be in a JSON API format/);
 });
+
+test("belongsTo relationship with links doesn't trigger extra change notifications - #4942", function(assert) {
+  Chapter.reopen({
+    book: DS.belongsTo({ async: true })
+  });
+
+  run(() => {
+    env.store.push({
+      data: {
+        type: 'chapter',
+        id: '1',
+        relationships: {
+          book: {
+            data: { type: 'book', id: '1' },
+            links: { related: '/chapter/1/book' }
+          }
+        }
+      },
+      included: [{ type: 'book', id: '1' }]
+    });
+  });
+
+  let chapter = env.store.peekRecord('chapter', '1');
+  let count = 0;
+
+  chapter.addObserver('book', () => {
+    count++;
+  });
+
+  run(() => {
+    chapter.get('book');
+  });
+
+  assert.equal(count, 0);
+});

tests/integration/relationships/has-many-test.js

@@ -3334,3 +3334,34 @@ test("deleted records should stay deleted", function(assert) {
     );
   });
 });
+
+test("hasMany relationship with links doesn't trigger extra change notifications - #4942", function(assert) {
+  run(() => {
+    env.store.push({
+      data: {
+        type: 'book',
+        id: '1',
+        relationships: {
+          chapters: {
+            data: [{ type: 'chapter', id: '1' }],
+            links: { related: '/book/1/chapters' }
+          }
+        }
+      },
+      included: [{ type: 'chapter', id: '1' }]
+    });
+  });
+
+  let book = env.store.peekRecord('book', '1');
+  let count = 0;
+
+  book.addObserver('chapters', () => {
+    count++;
+  });
+
+  run(() => {
+    book.get('chapters');
+  });
+
+  assert.equal(count, 0);
+});