Batch process stuck with error: Argument #2 ($haystack) must be of type array, null given in array_search()

Here's a patch for it.

I cannot reproduce the issue. We get the default value in the hook_install(). It looks like you're having some problem with that. But maybe it's related to the old issue #488000 → . Let's wait, if people get this issue, we'll set the default value in an extra location.

I removed hook_install() and also changed the code so that it does the same as your code:

$hashes = \Drupal::state()->get('image_field_to_media.hashes_of_image_files', []);

I hope this problem won't appear anymore.

Automatically closed - issue fixed for 2 weeks with no activity.