The active page number is not showing on the last page(Views Full pager)

Patch #3 Applied and Tested successfully on Drupal 9.5.x.

Before Patch:

After Patch:

Patch #3 do great work and Tested successfully on Drupal 9.5.x.

Thanks and Regards .

#3 Patch Applied on 9.5.x-dev and it fixes the issue.

1. +++ b/core/includes/theme.inc
   @@ -1883,6 +1883,18 @@ function template_preprocess_pager(&$variables) {
   +  // To show last active page when "Number of pager links visible"
   +  // is equals to one.
   

   This is not a proper English sentence. Maybe:
   "Make sure the current page is shown if only one page number is shown."
   or something?

2. +++ b/core/includes/theme.inc
   @@ -1883,6 +1883,18 @@ function template_preprocess_pager(&$variables) {
   +  if ($pager_max == $pager_current && $quantity == 1) {
   

   can we use '===' ?

3. +++ b/core/includes/theme.inc
   @@ -1883,6 +1883,18 @@ function template_preprocess_pager(&$variables) {
   +    $options = [
   +      'query' => $pager_manager->getUpdatedParameters($parameters, $element, $i - 1),
   +    ];
   +    $items['pages'][$i]['href'] = Url::fromRoute($route_name, $route_parameters, $options)->toString();
   +    $items['pages'][$i]['attributes'] = new Attribute();
   +    $variables['current'] = $i;
   

   Is all this really needed? Why is the link removed in the first place? Seems like we should do some more digging into why this breaks at all.

Also, this needs a test. And since the current fix has nothing to do with Views, this seems like a more general problem? But no idea which component this should go into, 'base system' sounds a bit weak too....

https://git.drupalcode.org/project/drupal/-/blob/9.5.x/core/includes/the...

if ($i != $pager_max) {
  // Add an ellipsis if there are further previous pages.
  if ($i > 1) {
    $variables['ellipses']['previous'] = TRUE;
  }
  // Now generate the actual pager piece.
  for (; $i <= $pager_last && $i <= $pager_max; $i++) {
    $options = [
      'query' => $pager_manager->getUpdatedParameters($parameters, $element, $i - 1),
    ];
    $items['pages'][$i]['href'] = Url::fromRoute($route_name, $route_parameters, $options)->toString();
    $items['pages'][$i]['attributes'] = new Attribute();
    if ($i == $pager_current) {
      $variables['current'] = $i;
    }
  }
  // Add an ellipsis if there are further next pages.
  if ($i < $pager_max + 1) {
    $variables['ellipses']['next'] = TRUE;
  }
}

This part is never executed for last page if pager quantity is set to 1. Unfortunately the logic behind the check if ($i != $pager_max) { is not documented.
It does not really add up because in the nested for loop $i is allowed to be equal with $pager_max
for (; $i <= $pager_last && $i <= $pager_max; $i++) {

Created a new patch that disables the check in question. Needs tests though.

Changing component

Issue summary needs to be updated for missing parts.

Confirmed on 11.x that the last page of a view has the active page link.

Made minor adjustments to the test on commit; adjusted the wrapping of the comment and simplified the selector a bit.

Committed 3da8c30 and pushed to 11.x. Also cherry-picked to 10.1.x. Thanks!

Not going to backport to 10.0.x or 9.5.x because there's a small behavior change.