MAGETWO-63704: [Backport] - Scheduled Update removes all simple variations from Configurable product - for 2.1

Author: Sergey Shvets

app/code/Magento/ConfigurableProduct/view/adminhtml/web/js/variations/variations.js

@@ -301,12 +301,8 @@ define([
          * Chose action for the form save button
          */
         saveFormHandler: function() {
-            this.source.data["product"]["configurable-matrix-serialized"] =
-                JSON.stringify(this.source.data["configurable-matrix"]);
-            delete this.source.data["configurable-matrix"];
-            this.source.data["product"]["associated_product_ids_serialized"] =
-                JSON.stringify(this.source.data["associated_product_ids"]);
-            delete this.source.data["associated_product_ids"];
+            this.serializeData();
+
             if (this.checkForNewAttributes()) {
                 this.formSaveParams = arguments;
                 this.attributeSetHandlerModal().openModal();
@@ -315,6 +311,29 @@ define([
             }
         },
 
+        /**
+         * Serialize data for specific form fields
+         *
+         * Get data from outdated fields, serialize it and produce new form fields.
+         *
+         * Outdated fields:
+         *   - configurable-matrix;
+         *   - associated_product_ids.
+         *
+         * New fields:
+         *   - configurable-matrix-serialized;
+         *   - associated_product_ids_serialized.
+         */
+        serializeData: function () {
+            this.source.data["product"]["configurable-matrix-serialized"] =
+                JSON.stringify(this.source.data["configurable-matrix"]);
+            delete this.source.data["configurable-matrix"];
+
+            this.source.data["product"]["associated_product_ids_serialized"] =
+                JSON.stringify(this.source.data["associated_product_ids"]);
+            delete this.source.data["associated_product_ids"];
+        },
+
         /**
          * Check for newly added attributes
          * @returns {Boolean}