Error on hooks "Storage for the page is immutable and cannot be deleted"

The CMS Questions
1

I’m opening a new topic as this one is marked “solved”.

On the page.update:after event I need to update $newpage twice, but I get the following error:

Storage for the page is immutable and cannot be deleted. Make sure to use the last alteration of the object.

I know that $newPage is immutable, so I reassign the returned object, but I get the error anyway. Here is the snippet of code in my config.php file.

else if ($newPage->template() == "album")
      { 
        //Split artista e titolo
        $newPage = trackAlbumUpdate($newPage, $oldPage, false);

        //Lowercase tags
        $newPage = lowerCaseTags($newPage);
      }

Of course I could merge both functions into one, and update the page one time only, but It would mess up my code…

Any input?
Thanks
Francesco

2

And what do those functions do? Without their code, it’s hard to tell.

3

They both update the txt file.

//Splitta artista e titolo dell'album o della traccia e aggiorna i tag
//Trasfroma i tag in minuscolo e aggiorna la pagina
function trackAlbumUpdate($newPage, $oldPage, $isTitleChanged)
{
  $artist = "";
  $title = "";
  $tags = $newPage->tags()->yaml();
  
  //Dal titolo ricava artista e titolo del pezzo e lo scrive sul file
  try{
      $arr = explode(':',$newPage->title());
      if ($arr[0] > "") $artist = trim($arr[0]);
      if ($arr[1] > "") $title = trim($arr[1]);
  }
  catch(Exception $e) {}; //echo $e;}
  
  //Aggiorno i tag con il nome dell'artista, se cambiato, o se nessun tag è valorizzato

  $newTags = array();
  $newTags = $tags;
  
  if ($isTitleChanged || count($tags) == 0)
  {
    array_push($tags, $artist);                     //Aggiungo ai tag il nome dell'artista
    $newTags = array_unique($tags, SORT_STRING);    //Rendo unico il contenuto
  }

  return $newPage->update(array(
      'artist' => $artist, 
      'articleTitle' => $title,
      'tags' => strtolower(implode(',',$newTags))
  ));
}

//Trasfroma i tag in minuscolo
//Aggiorna la pagina
function lowerCaseTags($page)
{
  return $page->update(array(
    'tags' => strtolower($page->tags())
  ));
}
4

Why are you updating the page twice?

Some things look weird in your code. Given that $newPage->tags() is a standard tags field, you need to split it to get an array.

Secondly,

Why is the $newTags variable directly overwritten, this is unnecessary.

Try/catch is unnecessary here, non of this throws an error. The code can be shortened to:

$tags = $newPage->tags()->split();
$arr = explode(':',$newPage->title());
$artist = trim($arr[0] ?? '');
$title = trim($arr[1] ?? '');
5

Do you return the new page object in your hook?

6

Thanks @texnixe for pushing me to improve my code and @distantnative for trying to solve my problem. I completely refactored my code and now it works, due the fact I managed to update the page one time only.

The only thing I’d like to know if it’s normal to get the “Immutable storage” error when I update the page twice in the same hook.

7

It should not happen if we continue to use the newly returned object. Basically with v5, Kirby marks an object explicitly as immutable when returning a modified version of the object (e.g. when calling update). To avoid you keep using the old object with outdated content.

8

My guess is rather that the errors in your original code resulted in an outdated $newPage variable.