MAGETWO-86918: Saving configurable product erases and reinserts records in table "catalog_product_super_link" even with no changes

Author: victor-v-rad

app/code/Magento/ConfigurableProduct/Model/Product/SaveHandler.php

@@ -10,6 +10,8 @@
 use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
 use Magento\ConfigurableProduct\Model\ResourceModel\Product\Type\Configurable as ResourceModelConfigurable;
 use Magento\Framework\EntityManager\Operation\ExtensionInterface;
+use Magento\ConfigurableProduct\Api\Data\OptionInterface;
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable\Attribute;
 
 /**
  * Class SaveHandler
@@ -87,11 +89,13 @@ private function saveConfigurableProductAttributes(ProductInterface $product, ar
         $ids = [];
         $existingAttributeIds = [];
         foreach ($this->optionRepository->getList($product->getSku()) as $option) {
-            $existingAttributeIds[] = $option->getAttributeId();
+            $existingAttributeIds[$option->getAttributeId()] = $option;
         }
         /** @var \Magento\ConfigurableProduct\Model\Product\Type\Configurable\Attribute $attribute */
         foreach ($attributes as $attribute) {
-            if (!in_array($attribute->getAttributeId(), $existingAttributeIds)) {
+            if (!in_array($attribute->getAttributeId(), array_keys($existingAttributeIds))
+                || $this->isOptionChanged($existingAttributeIds[$attribute->getAttributeId()], $attribute)
+            ) {
                 $attribute->setId(null);
                 $ids[] = $this->optionRepository->save($product->getSku(), $attribute);
             }
@@ -109,12 +113,31 @@ private function deleteConfigurableProductAttributes(ProductInterface $product)
     {
         $newAttributeIds = [];
         foreach ($product->getExtensionAttributes()->getConfigurableProductOptions() as $option) {
-            $newAttributeIds[] = $option->getAttributeId();
+            $newAttributeIds[$option->getAttributeId()] = $option;
         }
         foreach ($this->optionRepository->getList($product->getSku()) as $option) {
-            if (!in_array($option->getAttributeId(), $newAttributeIds)) {
+            if (!in_array($option->getAttributeId(), array_keys($newAttributeIds))
+                || $this->isOptionChanged($option, $newAttributeIds[$option->getAttributeId()])
+            ) {
                 $this->optionRepository->deleteById($product->getSku(), $option->getId());
             }
         }
     }
+
+    /**
+     * Check if existing option is changed
+     *
+     * @param OptionInterface $option
+     * @param Attribute $attribute
+     * @return bool
+     */
+    private function isOptionChanged(OptionInterface $option, Attribute $attribute)
+    {
+        if ($option->getLabel() == $attribute->getLabel()
+            && $option->getPosition() == $attribute->getPosition()
+        ) {
+            return false;
+        }
+        return true;
+    }
 }