Fixes issue with backorders enabled and qty < 0, is_in_stock = 1

app/code/Magento/CatalogImportExport/Model/Import/Product.php

@@ -3176,7 +3176,8 @@ private function formatStockDataForRow(array $rowData): array
         $stockItemDo = $this->stockRegistry->getStockItem($row['product_id'], $row['website_id']);
         $existStockData = $stockItemDo->getData();
 
-        if (isset($rowData['qty']) && $rowData['qty'] == 0 && !isset($rowData['is_in_stock'])) {
+        //If qty is <= 0 and is_in_stock is not set, we should set it to 0
+        if (isset($rowData['qty']) && $rowData['qty'] <= 0 && !isset($rowData['is_in_stock'])) {
             $rowData['is_in_stock'] = 0;
         }
 
@@ -3188,11 +3189,19 @@ private function formatStockDataForRow(array $rowData): array
         );
 
         if ($this->stockConfiguration->isQty($this->skuProcessor->getNewSku($sku)['type_id'])) {
-            if (isset($rowData['qty']) && $rowData['qty'] == 0) {
+
+            //if qty is 0 and backorders are not enabled, is_in_stock should become 0.
+            if (isset($rowData['qty']) && $rowData['qty'] <= 0 && !$stockItemDo->getBackorders()) {
                 $row['is_in_stock'] = 0;
             }
+
             $stockItemDo->setData($row);
-            $row['is_in_stock'] = $row['is_in_stock'] ?? $this->stockStateProvider->verifyStock($stockItemDo);
+
+            //if back-orders are not enabled, we can verify the stock.
+            if (!$stockItemDo->getBackorders()) {
+                $row['is_in_stock'] = $row['is_in_stock'] ?? $this->stockStateProvider->verifyStock($stockItemDo);
+            }
+
             if ($this->stockStateProvider->verifyNotification($stockItemDo)) {
                 $date = $this->dateTimeFactory->create('now', new \DateTimeZone('UTC'));
                 $row['low_stock_date'] = $date->format(DateTime::DATETIME_PHP_FORMAT);

dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php

@@ -2909,6 +2909,20 @@ public function testImportWithBackordersDisabled(): void
         $this->assertFalse($product->getDataByKey('quantity_and_stock_status')['is_in_stock']);
     }
 
+    /**
+     * Test that imported product stock status with stock quantity < 0 and backorders functionality enabled
+     * can be set to 'In stock'.
+     *
+     * @magentoDbIsolation enabled
+     * @magentoAppIsolation enabled
+     */
+    public function testInStockQtyEqualOrBelowZeroImportWithBackordersEnabled(): void
+    {
+        $this->importFile('products_to_import_with_backorders_enabled_in_stock_and_qty_0.csv');
+        $product = $this->getProductBySku('simple_new');
+        $this->assertTrue($product->getDataByKey('quantity_and_stock_status')['is_in_stock']);
+    }
+
     /**
      * Import file by providing import filename and bunch size.
      *

dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/_files/products_to_import_with_backorders_enabled_in_stock_and_qty_0.csv

@@ -0,0 +1,2 @@
+sku,store_view_code,attribute_set_code,product_type,categories,product_websites,name,description,short_description,weight,product_online,tax_class_name,visibility,price,special_price,special_price_from_date,special_price_to_date,url_key,meta_title,meta_keywords,meta_description,base_image,base_image_label,small_image,small_image_label,thumbnail_image,thumbnail_image_label,created_at,updated_at,new_from_date,new_to_date,display_product_options_in,map_price,msrp_price,map_enabled,gift_message_available,custom_design,custom_design_from,custom_design_to,custom_layout_update,page_layout,product_options_container,msrp_display_actual_price_type,country_of_manufacture,additional_attributes,qty,out_of_stock_qty,use_config_min_qty,is_qty_decimal,allow_backorders,use_config_backorders,min_cart_qty,use_config_min_sale_qty,max_cart_qty,use_config_max_sale_qty,is_in_stock,notify_on_stock_below,use_config_notify_stock_qty,manage_stock,use_config_manage_stock,use_config_qty_increments,qty_increments,use_config_enable_qty_inc,enable_qty_increments,is_decimal_divided,website_id,related_skus,crosssell_skus,upsell_skus,additional_images,additional_image_labels,hide_from_product_page,custom_options,bundle_price_type,bundle_sku_type,bundle_price_view,bundle_weight_type,bundle_values,associated_skus
+simple_new,,Default,simple,,base,New Product,,,,1,Taxable Goods,"Catalog, Search",10,,,,new-product,New Product,New Product,New Product ,,,,,,,10/20/2015 7:05,10/20/2015 7:05,,,Block after Info Column,,,,,,,,,,,,,"has_options=1,quantity_and_stock_status=In Stock,required_options=1",0,0,1,0,1,0,1,1,10000,1,1,1,1,1,0,1,1,0,0,0,1,,,,,,,,,,,,,