fixed batch filter clobbers array keys when fill parameter is used

CHANGELOG

@@ -1,5 +1,6 @@
 * 1.38.0 (2019-XX-XX)
 
+ * fixed batch filter clobbers array keys when fill parameter is used
  * added preserveKeys support for the batch filter
  * fixed "embed" support when used from "template_from_string"
  * added the possibility to pass a TemplateWrapper to Twig\Environment::load()

src/Extension/CoreExtension.php

@@ -1651,7 +1651,9 @@ function twig_array_batch($items, $size, $fill = null, $preserveKeys = true)
     if (null !== $fill && $result) {
         $last = \count($result) - 1;
         if ($fillCount = $size - \count($result[$last])) {
-            $result[$last] = array_merge($result[$last], array_fill(0, $fillCount, $fill));
+            for ($i = 0; $i < $fillCount; $i++) {
+                $result[$last][] = $fill;
+            }
         }
     }
 

test/Twig/Tests/Fixtures/filters/batch_with_more_elements.test

@@ -0,0 +1,23 @@
+--TEST--
+"batch" filter
+--TEMPLATE--
+{% for row in items|batch(3, 'fill') %}
+  <div class=row>
+  {% for key, column in row %}
+    <div class={{ key }}>{{ column }}</div>
+  {% endfor %}
+  </div>
+{% endfor %}
+--DATA--
+return ['items' => ['a' => 'a', 'b' => 'b', 'c' => 'c', 'd' => 'd', '123' => 'e']]
+--EXPECT--
+<div class=row>
+      <div class=a>a</div>
+      <div class=b>b</div>
+      <div class=c>c</div>
+    </div>
+  <div class=row>
+      <div class=d>d</div>
+      <div class=123>e</div>
+      <div class=124>fill</div>
+    </div>