Limit what can be called by a callback in form arrays

I'm able to get back to this issue after a good while dealing with other things. I'm going to look over the work I did before against 9.2 and update it against 10.1 in light of 📌 Deprecate TrustedCallbackInterface in favour of TrustedCallback attribute Needs work

FatherShawn → closed merge request !379

Refactoring against the 11.x branch

Thanks for changing the status @andypost. I’ll switch it when I finish this refactor

Tests finally passing for #process on 11.x

#after_build passed tests.

I’m looking at this section of code in FormBuilder

      // @todo Once all elements are converted to plugins in
      //   https://www.drupal.org/node/2311393, rely on
      //   $element['#value_callback'] directly.
      $value_callable = !empty($element['#value_callback']) ? $element['#value_callback'] : 'form_type_' . $element['#type'] . '_value';
      if (!is_callable($value_callable)) {
        $value_callable = '\Drupal\Core\Render\Element\FormElement::valueCallback';
      }

The #2311393: Remove hook_element_info() and all references to it → is long closed with associated change record → published 9 years ago. We have no form_type_TYPE_value functions in core now. It seems that this can be simplified and the @todo removed.

@FatherShawn re #46 is that 📌 Remove stale processing and reference to form_type_TYPE_value Needs review , I think I came to the same conclusion a few years back.

I fixed 📌 Remove stale processing and reference to form_type_TYPE_value Needs review as I was working on #value_callback here before I saw your comment @larowan. Thanks for connecting them! Can we simply close that issue when we close this one?

I would try to keep the scope as small as possible to ensure faster progress

Removing scope creep

Thanks for the review and the notes! If they prompt any questions I'll post on the MR - love that we can do that now!