Product->save() shouldn't be called directly

Here is a problem with calling Product->save() directly:

When product has custom options it should have 'has_options' and possibly 'required_options' set to true but calling Product->save() without $product->setCanSaveCustomOptions(true); will result in both 'has_options' and 'required_options' to be set to false.

Also calling $product->save() won't invalidate internal ProductRepository's cache (instances , instancesById) and this would produces other unexpected issues.

Author: stansm

app/code/Magento/Catalog/Model/ProductWebsiteLinkRepository.php

@@ -37,7 +37,7 @@ public function save(ProductWebsiteLinkInterface $productWebsiteLink)
         $product = $this->productRepository->get($productWebsiteLink->getSku());
         $product->setWebsiteIds(array_merge($product->getWebsiteIds(), [$productWebsiteLink->getWebsiteId()]));
         try {
-            $product->save();
+            $this->productRepository->save($product);
         } catch (\Exception $e) {
             throw new CouldNotSaveException(
                 __(
@@ -68,7 +68,7 @@ public function deleteById($sku, $websiteId)
         $product->setWebsiteIds(array_diff($product->getWebsiteIds(), [$websiteId]));
 
         try {
-            $product->save();
+            $this->productRepository->save($product);
         } catch (\Exception $e) {
             throw new CouldNotSaveException(
                 __(