Improve pagination exception & add total pages to page_info

Author: Daniël van der Linden

app/code/Magento/CatalogGraphQl/Model/Resolver/Products.php

@@ -110,10 +110,10 @@ public function resolve(
 
         $currentPage = $searchCriteria->getCurrentPage();
         if ($searchCriteria->getCurrentPage() > $maxPages && $searchResult->getTotalCount() > 0) {
-            $currentPage = new GraphQlInputException(
+            throw new GraphQlInputException(
                 __(
-                    'currentPage value %1 specified is greater than the number of pages available.',
-                    [$maxPages]
+                    'currentPage value %1 specified is greater than the %2 page(s) available.',
+                    [$currentPage, $maxPages]
                 )
             );
         }
@@ -123,7 +123,8 @@ public function resolve(
             'items' => $searchResult->getProductsSearchResult(),
             'page_info' => [
                 'page_size' => $searchCriteria->getPageSize(),
-                'current_page' => $currentPage
+                'current_page' => $currentPage,
+                'total_pages' => $maxPages
             ],
             'filters' => $this->filtersDataProvider->getData($layerType)
         ];

app/code/Magento/GraphQl/etc/schema.graphqls

@@ -29,6 +29,7 @@ input FilterTypeInput @doc(description: "FilterTypeInput specifies which action
 type SearchResultPageInfo @doc(description: "SearchResultPageInfo provides navigation for the query response") {
     page_size: Int @doc(description: "Specifies the maximum number of items to return")
     current_page: Int @doc(description: "Specifies which page of results to return")
+    total_pages: Int @doc(description: "Total amount of pages")
 }
 
 enum SortEnum @doc(description: "This enumeration indicates whether to return results in ascending or descending order") {