Empty query params on source cause TypeError

I encountered this problem after upgrading to php8, but when I used the patch package in composer.json, I was prompted that I could not apply it. I used the composer install -vvv command to get an error: can't find file to patch at input line 6 ; I did not find the file redirect.post_update.php; My project is drupal9.4.8, PHP8.

None of these fixes solved my problem, nor could I even apply the fix; I found another one, but it was so old that while his modification fixed the problem, it also couldn't be applied, so I Decided to upload a patch pack myself.
First describe my problem: my error is the same as here, and it is also caused by the upgrade of PHP to 8. I actually encountered an error when visiting /admin/config/search/redirect.

@River Zhao: Your patch is for core and doesn't belong here.

1. +++ b/redirect.post_update.php
   @@ -0,0 +1,37 @@
   +  foreach ($ids as $id) {
   +    $redirect = $storage->load($id);
   +    $values = $redirect->get('redirect_source')->getValue();
   +    if (empty($values[0]['query'])) {
   +      $values[0]['query'] = [];
   

   It's not quite clear to me why this does another empty check since you query for that already. If anything it would need to be an isset() && ==== NULL check? empty returns TRUE both if the key isn't set at all and if it's an empty array, so that doesn't do much.

   Also, you can just access the query with $redirect->get('redirect_source')->query and set it in the same way, makes this a lot simpler.

2. +++ b/src/Entity/Redirect.php
   @@ -90,6 +90,12 @@ class Redirect extends ContentEntityBase {
    
   +    $values = $this->get('redirect_source')->getValue();
   +    if (empty($values[0]['query'])) {
   +      $values[0]['query'] = [];
   +      $this->set('redirect_source', $values);
   +    }
   +
        // Get the language code directly from the field as language() might not
   

   I can't reproduce this error, what exactly is the backtrace?

   Instead of here, I would suggest that we handle this in \Drupal\redirect\Plugin\Field\FieldType\RedirectSourceItem, either in the toUrl() method, by not using query if it's not an array or in setValue() and make sure that query is always an array, that would likely avoid the update function entirely.

Taking Berdir's advice and trying to update the setValue() function in RedirectSourceItem.php. I also updated the isEmpty() check to be a more basic empty() check.

This is captured in the issue fork (and merge request) I created against this issue. But I'm capturing it here as a patch file for posterity as well.

Why did I update the isEmpty() check when it wasn't actually related to the query parameters? The world may never know. smh

I've reverted that portion of my patch. Reattaching here for posterity....again.