The Paragraphs Table module's clone form (`ParagraphCloneForm`) causes a fatal error in Drupal 11 when attempting to clone a paragraph.
The `ParagraphCloneForm` does not set a `#title` before calling the parent `buildForm()`. In Drupal 11, this leads to a `TypeError` during page rendering when the (null) title is passed to `Html::escape()` in `FormattableMarkup.php`.
Other forms in the module (add, edit, delete) avoid this by either setting a title explicitly or inheriting one from the route definition.
In this case, the paragraph being cloned is embedded inside another paragraph (nested), and its type does not define a label field. As a result, `$paragraph->label()` returns `NULL`, which causes the fatal error described.
**Note:** The Paragraphs module does not allow you to configure a label field via the UI. As a result, many paragraph types — especially nested ones — do not have a defined label, and `$paragraph->label()` simply returns `NULL`.
1. Ensure you're using **Drupal 11** and the **Paragraphs Table** module is installed.
2. Create a **Paragraph type** (e.g., “Assignment”) that includes a **Paragraphs Table field** (e.g., a `table` field of type Paragraphs Table).
3. Create another **Paragraph type** (e.g., “Row”) that is used inside the table.
4. Add several “Row” paragraphs inside an “Assignment” paragraph using the Paragraphs Table field.
5. Navigate to the Paragraphs Table view and click the **“Duplicate”** operation for one of the nested “Row” paragraphs.
6. Observe that the page throws a **TypeError** due to `Html::escape(NULL)`.
Update the `ParagraphCloneForm::buildForm()` method to explicitly set a fallback title **before** calling `parent::buildForm()`. This ensures the form always has a valid, non-null `#title`, avoiding the fatal error.
Suggested fix:
```php
public function buildForm(array $form, FormStateInterface $form_state) {
$form = parent::buildForm($form, $form_state);
// Ensure the form has a page title.
$form['#title'] = $this->t('Duplicate paragraph: @label', [
'@label' => $this->entity->label() ?: $this->t('(No label)'),
]);
return $form;
}
```
- Confirm that the proposed fix prevents the fatal error when `$paragraph->label()` returns `NULL`.
- Optionally: Create and review a patch with the proposed fix.
- Test with nested paragraph types that lack label fields.
- Optionally: Discuss whether Paragraphs module should expose a label field configuration.
None, unless the error occurs — in which case this change prevents the form from breaking.
None.
This fix only modifies the internal behavior of ParagraphCloneForm::buildForm() by ensuring a safe value is passed to #title. No public methods, services, or APIs are introduced or altered.
None.
This fix does not alter the structure or storage of paragraph entities.
Active
2.0
Code
I'd be happy to be assigned to this issue and help maintain the patch
@marjose would you mind creating a MR with the proposed fix?
Are you trying to create a patch on the development version? I don't think it's necessary to add this method, as I verified on my local host that it works correctly.