ValueError: "Drupal\Core\Template\Attribute" is not a valid backing value for enum

Hi @kiwad,
I've installed the experience builder on drupal cms project but I didn't get any error.

got the same error with Drupal 11.1.7

The version in the issue summary is ancient 😅

Without concrete steps to reproduce on the latest release of XB this is not actionable I’m afraid 🙈

Steps to reproduce:

PHP 8.3.6, Composer 8.3.6

1. Download latest Drupal (11.2.2): composer create-project drupal/recommended-project .
2. Install Drush (optional): composer require drush/drush
3. Install Drupal 11.2.2 with Standard profile: drush si standard
4. Install latest Experience Builder (0.5.0-alpha1): composer require 'drupal/experience_builder:^0.5@alpha'
5. Download latest Radix theme (6.0.2): composer require 'drupal/radix:^6.0'
6. Visit /admin/appearance form, install and set as default Radix theme
7. Go to /admin/modules page and enable Experience Builder module

I took a quick look at the SDCs in the Radix theme, and I spotted something that might cause this. It's just a guess.

Here are three SDCs that have props with an enum attribute and their type defined as an array:

1. carousel.component.yml
2. image.component.yml
3. page-content.component.yml

My guess is that \Drupal\experience_builder\JsonSchemaInterpreter is not expecting type as an array, or at least it's not expecting it when there is an enum attribute.

Radix 6.0.2 SDC components:

Wrong:

• accordion
• badge
• block
• breadcrumb
• button
• button-group
• card
• comment
• details
• dropdown
• field
• field-comment
• fieldset
• figure
• form-element
• form-element--label
• form-element--radiocheckbox
• heading
• list-group
• media
• modal
• nav-item
• node
• offcanvas
• page
• page-footer
• page-title
• select
• spinner
• taxonomy
• toasts
• views-view

Ok:

• alert
• close-button
• collapse
• dropdown-menu
• form
• html
• input
• local-tasks
• nav
• navbar
• navbar-brand
• page-navigation
• pagination
• progress
• radios
• region
• table
• textarea
• tooltips
• user
• views-view--grid
• views-view--table
• views-view--unformatted

Related to ✨ How to pass content_attributes to SDC without it being shown in the XB UI Active (probably even duplicated)

So probably any SDC is problematic where a prop's type is an array. This, as I come to think about it more, may not be very surprising: XB's prop shape matching needs to result in a deterministic field type + settings, and a field widget. Allowing multiple types would require us to generate UI that allows the user to select the type first. But I'm getting out of my depth, so curious what @wim leers or @penyaskito say. 🙂

AFAIK array is supported, as far as items specify the type.

See \Drupal\experience_builder\PropShape\PropShape::resolveSchemaReferences

Not that sure when using several types (e.g. type:[string, array] for a prop

Updated the issue summary based on what we know so far. I think what I said in #7 should be ignored based on the subsequent comments and a quick testing I did.

It needs more investigation to figure what exactly causes this error.

The answer is AFAICT surprisingly simple: it's not valid JSON Schema! SDC uses a superset — see @e0ipso's comment at #3352063-14: Allow schema references in Single Directory Component prop schemas → .

The solution is ✨ How to pass content_attributes to SDC without it being shown in the XB UI Active , so marking this as a duplicate and tagged that as a beta blocker + contributed project blocker.