MC-30260: CatalogWidget products list doesn't display products from the children categories of 2nd level and up

Author: Roman Lytvynenko

app/code/Magento/CatalogWidget/Block/Product/ProductsList.php

@@ -373,9 +373,9 @@ private function updateAnchorCategoryConditions(array $condition): array
                 return $condition;
             }
 
-            if ($category->getIsAnchor() && $category->getChildren(true)) {
-                $children = explode(',', $category->getChildren(true));
-
+            $children = $category->getIsAnchor() ? $category->getChildren(true) : [];
+            if ($children) {
+                $children = explode(',', $children);
                 $condition['operator'] = "()";
                 $condition['value'] = array_merge([$categoryId], $children);
             }

dev/tests/integration/testsuite/Magento/Catalog/_files/product_in_nested_anchor_categories.php

@@ -16,13 +16,13 @@
         'id' => 445,
         'parentId' => 444,
         'level' => 3,
-        'path' => '1/2/4'
+        'path' => '1/2/3/4'
     ],
     [
         'id' => 446,
         'parentId' => 445,
         'level' => 4,
-        'path' => '1/2/5'
+        'path' => '1/2/3/4/5'
     ],
 ];