Deprecate Ember.merge

packages/@ember/deprecated-features/index.ts

@@ -11,3 +11,4 @@ export const ARRAY_AT_EACH = !!'3.1.0-beta.1';
 export const TARGET_OBJECT = !!'2.18.0-beta.1';
 export const MAP = !!'3.3.0-beta.1';
 export const ORDERED_SET = !!'3.3.0-beta.1';
+export const MERGE = !!'3.6.0-beta.1';

packages/@ember/polyfills/index.ts

@@ -1,3 +1,8 @@
+import { MERGE } from '@ember/deprecated-features';
+import { default as deprecatedMerge } from './lib/merge';
+
+let merge = MERGE ? deprecatedMerge : undefined;
+
 // Export `assignPolyfill` for testing
 export { default as assign, assign as assignPolyfill } from './lib/assign';
-export { default as merge } from './lib/merge';
+export { merge };

packages/@ember/polyfills/lib/merge.ts

@@ -1,3 +1,5 @@
+import { deprecate } from '@ember/debug';
+
 /**
  @module @ember/polyfills
 */
@@ -25,6 +27,12 @@ export default function merge<T, U>(original: T, updates: U): T & U;
   @public
 */
 export default function merge(original: object, updates: object) {
+  deprecate('Use of `merge` has been deprecated. Please use `assign` instead.', false, {
+    id: 'ember-polyfills.deprecate-merge',
+    until: '4.0.0',
+    url: 'https://emberjs.com/deprecations/v3.x/#toc_ember-polyfills-deprecate-merge',
+  });
+
   if (updates === null || typeof updates !== 'object') {
     return original;
   }

packages/@ember/polyfills/tests/merge_test.js

@@ -0,0 +1,21 @@
+import { merge } from '..';
+import { moduleFor, AbstractTestCase } from 'internal-test-helpers';
+
+moduleFor(
+  'Ember.merge',
+  class extends AbstractTestCase {
+    ['@test merging objects'](assert) {
+      let src1 = { a: 1 };
+      let src2 = { b: 2 };
+      expectDeprecation(() => {
+        merge(src1, src2);
+      }, 'Use of `merge` has been deprecated. Please use `assign` instead.');
+
+      assert.deepEqual(
+        src1,
+        { a: 1, b: 2 },
+        'merge copies values from second source object to first object'
+      );
+    }
+  }
+);

packages/internal-test-helpers/lib/system/synthetic-events.js

@@ -1,7 +1,7 @@
 import { run } from '@ember/runloop';
 /* globals Element */
 
-import { merge } from '@ember/polyfills';
+import { assign } from '@ember/polyfills';
 
 const DEFAULT_EVENT_OPTIONS = { canBubble: true, cancelable: true };
 const KEYBOARD_EVENT_TYPES = ['keydown', 'keypress', 'keyup'];
@@ -112,7 +112,7 @@ export function fireEvent(element, type, options = {}) {
       clientX: x,
       clientY: y,
     };
-    event = buildMouseEvent(type, merge(simulatedCoordinates, options));
+    event = buildMouseEvent(type, assign(simulatedCoordinates, options));
   } else {
     event = buildBasicEvent(type, options);
   }
@@ -124,16 +124,15 @@ export function fireEvent(element, type, options = {}) {
 function buildBasicEvent(type, options = {}) {
   let event = document.createEvent('Events');
   event.initEvent(type, true, true);
-  merge(event, options);
+  assign(event, options);
   return event;
 }
 
 function buildMouseEvent(type, options = {}) {
   let event;
   try {
     event = document.createEvent('MouseEvents');
-    let eventOpts = merge({}, DEFAULT_EVENT_OPTIONS);
-    merge(eventOpts, options);
+    let eventOpts = assign({}, DEFAULT_EVENT_OPTIONS, options);
 
     event.initMouseEvent(
       type,
@@ -162,8 +161,7 @@ function buildKeyboardEvent(type, options = {}) {
   let event;
   try {
     event = document.createEvent('KeyEvents');
-    let eventOpts = merge({}, DEFAULT_EVENT_OPTIONS);
-    merge(eventOpts, options);
+    let eventOpts = assign({}, DEFAULT_EVENT_OPTIONS, options);
     event.initKeyEvent(
       type,
       eventOpts.canBubble,