Unable to change menu items weight when the "system.site.weight_select_max" exceeded and "#pre_render" for "number" element is modified

+++ b/core/lib/Drupal/Core/Render/Element/Weight.php
@@ -32,29 +32,32 @@ class Weight extends FormElement {
+    $element = array_merge($element, \Drupal::service('element_info')->getInfo($type));
+    $element['#type'] = $type;

Is it a good idea to use only one condition, and move those lines after it
Like
if ($element['#delta'] <= $max_elements) {
...
}
else {...}
then
$element = array_merge($element, \Drupal::service('element_info')->getInfo($type));
$element['#type'] = $type;

#10 is more of a style question.
I opt for #9 to be RTBC, it is a good and pretty solution of the problem. Thanks @BR0kEN!

1. +++ b/core/lib/Drupal/Core/Render/Element/Weight.php
   @@ -32,29 +32,32 @@ class Weight extends FormElement {
   -    $class = get_class($this);
   ...
   -        [$class, 'processWeight'],
   -        [$class, 'processAjaxForm'],
   +        [static::class, 'processWeight'],
   +        [static::class, 'processAjaxForm'],
   

   Is this change necessary? Hopefully not because a lot of render items do this. Well it seems it might be - https://3v4l.org/JKNf8 - but this is a separate issue no? Not actually necessary to fix the bug here is it?

2. +++ b/core/lib/Drupal/Core/Render/Element/Weight.php
   @@ -32,29 +32,32 @@ class Weight extends FormElement {
   +    $type = $element['#delta'] <= \Drupal::config('system.site')->get('weight_select_max')
   +      // If the number of options is small enough, use a select field.
   +      ? 'select'
   +      // Otherwise, use a text field.
   +      : 'number';
   

   Placing this on multiple lines is very confusing for a ternary. If we're using a ternary I think it should be on one line. The comments can go on the line before.

3. Also from reading the issue summary this fix might boil down to:
   

   diff --git a/core/lib/Drupal/Core/Render/Element/Weight.php b/core/lib/Drupal/Core/Render/Element/Weight.php
   index 649de315fd..3f67eae93e 100644
   --- a/core/lib/Drupal/Core/Render/Element/Weight.php
   +++ b/core/lib/Drupal/Core/Render/Element/Weight.php
   @@ -65,14 +65,14 @@ public static function processWeight(&$element, FormStateInterface $form_state,
            ksort($weights);
          }
          $element['#options'] = $weights;
   -      $element += $element_info_manager->getInfo('select');
   +      $element = array_merge($element, $element_info_manager->getInfo('select'));
        }
        // Otherwise, use a text field.
        else {
          $element['#type'] = 'number';
          // Use a field big enough to fit most weights.
          $element['#size'] = 10;
   -      $element += $element_info_manager->getInfo('number');
   +      $element = array_merge($element, $element_info_manager->getInfo('number'));
        }
    
        return $element;
   

   If that's the case can we limit the change to that because it makes it way easier to review.

I think all points from #14 have been addressed.

Committed and pushed d90d0ebbda to 8.8.x and d77f9a680e to 8.7.x. Thanks!

diff --git a/core/lib/Drupal/Core/Render/Element/Weight.php b/core/lib/Drupal/Core/Render/Element/Weight.php
index e04d44903b..029c9e4a49 100644
--- a/core/lib/Drupal/Core/Render/Element/Weight.php
+++ b/core/lib/Drupal/Core/Render/Element/Weight.php
@@ -48,11 +48,9 @@ public function getInfo() {
    * Expands a weight element into a select/number element.
    */
   public static function processWeight(&$element, FormStateInterface $form_state, &$complete_form) {
-    // If the number of options is small enough, use a select field.
-    // Otherwise, use a text field.
+    // If the number of options is small enough, use a select field. Otherwise,
+    // use a number field.
     $type = $element['#delta'] <= \Drupal::config('system.site')->get('weight_select_max') ? 'select' : 'number';
-    // Merge arrays in order to ensure the keys will be overridden. The
-    // concatenation is prohibited.
     $element = array_merge($element, \Drupal::service('element_info')->getInfo($type));
     $element['#is_weight'] = TRUE;
 
@@ -68,7 +66,6 @@ public static function processWeight(&$element, FormStateInterface $form_state,
       }
       $element['#options'] = $weights;
     }
-    // Otherwise, use a text field.
     else {
       // Use a field big enough to fit most weights.
       $element['#size'] = 10;
diff --git a/core/tests/Drupal/KernelTests/Core/Render/Element/WeightTest.php b/core/tests/Drupal/KernelTests/Core/Render/Element/WeightTest.php
index bd00173278..b44b98cf12 100644
--- a/core/tests/Drupal/KernelTests/Core/Render/Element/WeightTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Render/Element/WeightTest.php
@@ -116,7 +116,7 @@ public function testProcessWeightSelectMax() {
       ],
       '#pre_render' => [
         [Number::class, 'preRenderNumber'],
-        // Our custom callback is just appended.
+        // The custom callback is appended.
         /* @see element_info_test_element_info_alter() */
         'element_info_test_element_pre_render',
       ],

Fixed up some comments on commit.