Add new emptyStringAsHighest to sorting

Similar to `nullAsHighest`, it allows to control where empty string
values appear in a sorting.

Author: PowerKiKi

src/Factory/FilteredQueryBuilderFactory.php

@@ -155,6 +155,13 @@ private function applySorting(ClassMetadata $metadata, string $className, array
                     $this->queryBuilder->addOrderBy($sortingFieldNullAsHighest, $sort['order']);
                 }
 
+                if ($sort['emptyStringAsHighest'] ?? false) {
+                    $expression = 'CASE WHEN ' . $sortingField . ' = \'\' THEN 1 ELSE 0 END';
+                    $sortingFieldEmptyStringAsHighest = $this->uniqueNameFactory->createAliasName('sorting');
+                    $this->queryBuilder->addSelect($expression . ' AS HIDDEN ' . $sortingFieldEmptyStringAsHighest);
+                    $this->queryBuilder->addOrderBy($sortingFieldEmptyStringAsHighest, $sort['order']);
+                }
+
                 $this->queryBuilder->addOrderBy($sortingField, $sort['order']);
             }
         }

src/Factory/Type/SortingTypeFactory.php

@@ -57,6 +57,12 @@ public function create(string $className, string $typeName): Type
                         'description' => 'If true `NULL` values will be considered as the highest value, so appearing last in a `ASC` order, and first in a `DESC` order.',
                         'defaultValue' => false,
                     ],
+                    [
+                        'name' => 'emptyStringAsHighest',
+                        'type' => Type::boolean(),
+                        'description' => 'If true empty strings (`""`) will be considered as the highest value, so appearing last in a `ASC` order, and first in a `DESC` order.',
+                        'defaultValue' => false,
+                    ],
                     [
                         'name' => 'order',
                         'type' => $this->types->get('SortingOrder'),

tests/data/ModelWithTraitsSorting.graphqls

@@ -10,6 +10,12 @@ input ModelWithTraitsSorting {
   last in a `ASC` order, and first in a `DESC` order.
   """
   nullAsHighest: Boolean = false
+
+  """
+  If true empty strings (`""`) will be considered as the highest value, so
+  appearing last in a `ASC` order, and first in a `DESC` order.
+  """
+  emptyStringAsHighest: Boolean = false
   order: SortingOrder = ASC
 }
 

tests/data/PostSorting.graphqls

@@ -10,6 +10,12 @@ input PostSorting {
   last in a `ASC` order, and first in a `DESC` order.
   """
   nullAsHighest: Boolean = false
+
+  """
+  If true empty strings (`""`) will be considered as the highest value, so
+  appearing last in a `ASC` order, and first in a `DESC` order.
+  """
+  emptyStringAsHighest: Boolean = false
   order: SortingOrder = ASC
 }
 

tests/data/UserSorting.graphqls

@@ -16,6 +16,12 @@ input UserSorting {
   last in a `ASC` order, and first in a `DESC` order.
   """
   nullAsHighest: Boolean = false
+
+  """
+  If true empty strings (`""`) will be considered as the highest value, so
+  appearing last in a `ASC` order, and first in a `DESC` order.
+  """
+  emptyStringAsHighest: Boolean = false
   order: SortingOrder = ASC
 }
 

tests/data/query-builder/sort-with-empty-string-first.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+// all posts sorted by reversed title but with null title first
+return [
+    'SELECT post1, CASE WHEN post1.title = \'\' THEN 1 ELSE 0 END AS HIDDEN sorting1 FROM GraphQLTests\Doctrine\Blog\Model\Post post1 ORDER BY sorting1 DESC, post1.title DESC',
+    \GraphQLTests\Doctrine\Blog\Model\Post::class,
+    [],
+    [
+        [
+            'field' => 'title',
+            'order' => 'DESC',
+            'emptyStringAsHighest' => true,
+        ],
+    ],
+];

tests/data/query-builder/sort-with-empty-string-last.php

@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+// all posts sorted by title but with null title last
+return [
+    'SELECT post1, CASE WHEN post1.title = \'\' THEN 1 ELSE 0 END AS HIDDEN sorting1 FROM GraphQLTests\Doctrine\Blog\Model\Post post1 ORDER BY sorting1 ASC, post1.title ASC',
+    \GraphQLTests\Doctrine\Blog\Model\Post::class,
+    [],
+    [
+        [
+            'field' => 'title',
+            'emptyStringAsHighest' => true,
+            'order' => 'ASC',
+        ],
+    ],
+];