Use one format in all places for array_merge

Fix potential issues when no items in array
Convert all array_merge into single format

Author: ihor-sviziev

app/code/Magento/Catalog/Block/Product/ListProduct.php

@@ -367,7 +367,7 @@ public function getIdentities()
                 $identities[] = $item->getIdentities();
             }
         }
-        $identities = array_merge(...$identities);
+        $identities = array_merge([], ...$identities);
 
         return $identities;
     }

app/code/Magento/Catalog/Block/Product/ProductList/Related.php

@@ -143,11 +143,11 @@ public function getItems()
      */
     public function getIdentities()
     {
-        $identities = [[]];
+        $identities = [];
         foreach ($this->getItems() as $item) {
             $identities[] = $item->getIdentities();
         }
-        return array_merge(...$identities);
+        return array_merge([], ...$identities);
     }
 
     /**

app/code/Magento/Catalog/Block/Product/ProductList/Upsell.php

@@ -267,10 +267,10 @@ public function getItemLimit($type = '')
      */
     public function getIdentities()
     {
-        $identities = array_map(function (DataObject $item) {
-            return $item->getIdentities();
-        }, $this->getItems()) ?: [[]];
-
-        return array_merge(...$identities);
+        $identities = [];
+        foreach ($this->getItems() as $item) {
+            $identities[] = $item->getIdentities();
+        }
+        return array_merge([], ...$identities);
     }
 }

app/code/Magento/Catalog/Model/Indexer/Product/Category/Action/Rows.php

@@ -270,14 +270,14 @@ private function getCategoryIdsFromIndex(array $productIds): array
             );
             $categoryIds[] = $storeCategories;
         }
-        $categoryIds = array_merge(...$categoryIds);
+        $categoryIds = array_merge([], ...$categoryIds);
 
         $parentCategories = [$categoryIds];
         foreach ($categoryIds as $categoryId) {
             $parentIds = explode('/', $this->getPathFromCategoryId($categoryId));
             $parentCategories[] = $parentIds;
         }
-        $categoryIds = array_unique(array_merge(...$parentCategories));
+        $categoryIds = array_unique(array_merge([], ...$parentCategories));
 
         return $categoryIds;
     }

app/code/Magento/Catalog/Model/Indexer/Product/Flat/FlatTableBuilder.php

@@ -261,7 +261,7 @@ protected function _fillTemporaryFlatTable(array $tables, $storeId, $valueFieldS
 
         $select->from(
             ['et' => $entityTemporaryTableName],
-            array_merge(...$allColumns)
+            array_merge([], ...$allColumns)
         )->joinInner(
             ['e' => $this->resource->getTableName('catalog_product_entity')],
             'e.entity_id = et.entity_id',
@@ -306,7 +306,7 @@ protected function _fillTemporaryFlatTable(array $tables, $storeId, $valueFieldS
                 $allColumns[] = $columnValueNames;
             }
         }
-        $sql = $select->insertFromSelect($temporaryFlatTableName, array_merge(...$allColumns), false);
+        $sql = $select->insertFromSelect($temporaryFlatTableName, array_merge([], ...$allColumns), false);
         $this->_connection->query($sql);
     }
 

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

@@ -835,10 +835,7 @@ public function getStoreIds()
                     $storeIds[] = $websiteStores;
                 }
             }
-            if ($storeIds) {
-                $storeIds = array_merge(...$storeIds);
-            }
-            $this->setStoreIds($storeIds);
+            $this->setStoreIds(array_merge([], ...$storeIds));
         }
         return $this->getData('store_ids');
     }

app/code/Magento/Catalog/Model/Product/Price/TierPriceStorage.php

@@ -220,7 +220,7 @@ private function retrieveAffectedIds(array $skus): array
             $affectedIds[] = array_keys($productId);
         }
 
-        return $affectedIds ? array_unique(array_merge(...$affectedIds)) : [];
+        return array_unique(array_merge([], ...$affectedIds));
     }
 
     /**

app/code/Magento/Catalog/Model/ProductLink/ProductLinkQuery.php

@@ -103,7 +103,7 @@ private function extractRequestedLinkTypes(array $criteria): array
             if (count($linkTypesToLoad) === 1) {
                 $linkTypesToLoad = $linkTypesToLoad[0];
             } else {
-                $linkTypesToLoad = array_merge(...$linkTypesToLoad);
+                $linkTypesToLoad = array_merge([], ...$linkTypesToLoad);
             }
             $linkTypesToLoad = array_flip($linkTypesToLoad);
             $linkTypes = array_filter(

app/code/Magento/Catalog/Model/ResourceModel/Product/LinkedProductSelectBuilderComposite.php

@@ -33,7 +33,7 @@ public function build(int $productId, int $storeId) : array
         foreach ($this->linkedProductSelectBuilder as $productSelectBuilder) {
             $selects[] = $productSelectBuilder->build($productId, $storeId);
         }
-        $selects = array_merge(...$selects);
+        $selects = array_merge([], ...$selects);
 
         return $selects;
     }

app/code/Magento/CatalogGraphQl/DataProvider/Product/LayeredNavigation/Builder/Attribute.php

@@ -155,6 +155,10 @@ function (AggregationValueInterface $value) {
             return [];
         }
 
-        return $this->attributeOptionProvider->getOptions(\array_merge(...$attributeOptionIds), $storeId, $attributes);
+        return $this->attributeOptionProvider->getOptions(
+            \array_merge([], ...$attributeOptionIds),
+            $storeId,
+            $attributes
+        );
     }
 }