pass args to super

addon/index.js

@@ -5,7 +5,7 @@ import isEqual from 'lodash-es/isEqual';
 
 export default Mixin.create({
   init() {
-    this._super();
+    this._super(...arguments);
     this._relationshipTracker = Object.create(null);
   },
 

tests/integration/mixins/track-relationships-test.js

@@ -1,6 +1,7 @@
 import Model, { hasMany, belongsTo, attr } from '@ember-data/model';
 import JSONAPISerializer from '@ember-data/serializer/json-api';
 import { run } from '@ember/runloop';
+import EmberObject from '@ember/object';
 import { resolve, all } from 'rsvp';
 import { module, test } from 'qunit';
 import { setupRenderingTest } from 'ember-qunit';
@@ -417,3 +418,17 @@ module('Integration | Mixin | track relationships as Class', function(hooks) {
     });
   });
 });
+
+module('Integration | Mixin | base class init receives args', function () {
+  test('it receives args', function (assert) {
+    let receivedArgs;
+    class ExampleModel extends EmberObject.extend(TrackRelationships) {
+      init() {
+        receivedArgs = arguments;
+      }
+    }
+    const model = new ExampleModel();
+    model.init(['a', 3]);
+    assert.deepEqual(receivedArgs, ['a', 3]);
+  });
+});