Deprecate adapterFetch mixin

README.md

@@ -51,6 +51,9 @@ To use `ember-fetch` with TypeScript or enable editor's type support, You can ad
 ```
 
 ### Use with Ember Data
+
+> [email protected] was released with built-in fetch support, this mixin is no longer needed and will be removed in next major bump.
+
 To have Ember Data utilize `fetch` instead of jQuery.ajax to make calls to your backend, extend your project's `application` adapter with the `adapter-fetch` mixin.
 
 ```js

addon/mixins/adapter-fetch.ts

@@ -1,5 +1,6 @@
 import Mixin from '@ember/object/mixin';
 import { assign } from '@ember/polyfills';
+import { deprecate } from '@ember/debug';
 import RSVP, { reject } from 'rsvp';
 import fetch from 'fetch';
 import mungOptionsForFetch from '../utils/mung-options-for-fetch';
@@ -33,6 +34,7 @@ export function headersToObject(headers: Headers) {
 
 export interface FetchAdapter {
   headers: undefined | PlainHeaders;
+  init(): void;
   ajaxOptions(url: string, type: Method, options: object): FetchOptions;
   ajax(url: string, type: Method, options: object): RSVP.Promise<void>;
   _ajaxRequest(
@@ -60,6 +62,15 @@ export interface FetchAdapter {
 
 export default Mixin.create<FetchAdapter, DS.RESTAdapter>({
   headers: undefined,
+
+  init() {
+    this._super(...arguments);
+    deprecate('FetchAdapter is deprecated, it is no longer required for ember-data>=3.9.2', false, {
+      id: 'deprecate-fetch-ember-data-support',
+      until: '7.0.0'
+    });
+  },
+
   /**
    * @override
    */

tests/test-helper.js

@@ -2,7 +2,14 @@ import Application from '../app';
 import config from '../config/environment';
 import { setApplication } from '@ember/test-helpers';
 import { start } from 'ember-qunit';
+import { registerDeprecationHandler } from '@ember/debug';
 
 setApplication(Application.create(config.APP));
 
+registerDeprecationHandler((msg, options, next) => {
+  if (options.id !== 'deprecate-fetch-ember-data-support') {
+    next(msg, options);
+  }
+})
+
 start();

types/index.d.ts

@@ -0,0 +1,18 @@
+declare module "@ember/debug" {
+  // tslint:disable-next-line:strict-export-declare-modifiers
+  interface DeprecationOptions {
+    id: string;
+    until: string;
+    url?: string;
+  }
+
+  /**
+   * Display a deprecation warning with the provided message and a stack trace
+   * (Chrome and Firefox only).
+   */
+  export function deprecate(
+      message: string,
+      test: boolean,
+      options: DeprecationOptions
+  ): any;
+}