Magento – Magento 2 CMS Page getList() repository methods does not return expected object

I need to delete all CMS pages.

Here is the code:

namespace Soon\Core\Setup;

use Magento\Cms\Api\PageRepositoryInterface;
use Magento\Framework\Api\SearchCriteriaInterface;

class Cms
{
    /**
     * @var SearchCriteriaInterface
     */
    private $searchCriteria;
    /**
     * @var PageRepositoryInterface
     */
    private $cmsPageRepository;

    /**
     * Cms constructor.
     * @param SearchCriteriaInterface $searchCriteria
     * @param PageRepositoryInterface $cmsPageRepository
     */
    public function __construct(
        SearchCriteriaInterface $searchCriteria,
        PageRepositoryInterface $cmsPageRepository
    )
    {
        $this->searchCriteria = $searchCriteria;
        $this->cmsPageRepository = $cmsPageRepository;
    }

    /**
     * Delete all existing CMS pages
     */
    public function cleanCmsPages()
    {
        $cmsPageCollection = $this->cmsPageRepository
            ->getList($this->searchCriteria)
            ->getItems();

        foreach ($cmsPageCollection as $cmsPage) {
            $this->cmsPageRepository->delete($cmsPage);
        }
    }
}

So, calling \Soon\Core\Setup\Cms::cleanCmsPages should delete all CMS pages.

But when doing so, I get this error:

Argument 1 passed to Magento\Cms\Model\PageRepository::delete() must implement interface Magento\Cms\Api\Data\PageInterface, array given

So I dumped the $cmsPage used in my foreach ($cmsPageCollection as $cmsPage) and it appears that, indeed, $cmsPage is an array.

I digged into the code:

\Magento\Cms\Api\PageRepositoryInterface::getList is implemented by \Magento\Cms\Model\PageRepository::getList.

Then in \Magento\Cms\Model\PageRepository::getList, we can see this bit of code:

            $pages[] = $this->dataObjectProcessor->buildOutputDataArray(
                $pageData,
                'Magento\Cms\Api\Data\PageInterface'
            );
        }
        $searchResults->setItems($pages);

If I am correct, this code creates an array that populates the $pages array.
So this code may explain why $cmsPage is an array!

BUT…

By reading @return statement of \Magento\Cms\Api\PageRepositoryInterface::getList, we can see @return \Magento\Cms\Api\Data\PageSearchResultsInterface.

And, then by reading the @return statement from \Magento\Cms\Api\Data\PageSearchResultsInterface::getItems, we can see \Magento\Cms\Api\Data\PageInterface[]!

So the $cmsPage in my foreach loop should be an implementation of \Magento\Cms\Api\Data\PageInterface which then can be passed properly to \Magento\Cms\Api\PageRepositoryInterface::delete.

Who's wrong?

1. Me who cannot read / understand @api comments and code properly
2. Magento who whether does not give the right comment in their @api classes… or does not implements the interface as it should.

This analysis is for the CMS Page API but also applies to the CMS Block API.