Logic Exception with preview button for block-comment

@roynilanjan have you got an contrib or custom modules installed? If I follow the steps in the issue summary I can preview the comment just fine...

Confirm the failure, I got standard profile with content translation enabled

The website encountered an unexpected error. Please try again later.

LogicException: The database connection is not serializable. This probably means you are serializing an object that has an indirect reference to the database connection. Adjust your code so that is not necessary. Alternatively, look at DependencySerializationTrait as a temporary solution. in Drupal\Core\Database\Connection->__sleep() (line 1433 of core/lib/Drupal/Core/Database/Connection.php).

serialize(Array)
Drupal\Component\Serialization\PhpSerialize::encode(Array)
Drupal\Core\KeyValueStore\DatabaseStorageExpirable->setWithExpire('form-WRU2jWJrJfgNhZbfbdQpAlME4B2QzUHvp27AzhSelME', Array, 21600)
Drupal\Core\Form\FormCache->setCache('form-WRU2jWJrJfgNhZbfbdQpAlME4B2QzUHvp27AzhSelME', Array, Object)
Drupal\Core\Form\FormBuilder->setCache('form-WRU2jWJrJfgNhZbfbdQpAlME4B2QzUHvp27AzhSelME', Array, Object)
Drupal\Core\Form\FormBuilder->rebuildForm('comment_block_form', Object, Array)
Drupal\Core\Form\FormBuilder->processForm('comment_block_form', Array, Object)
Drupal\Core\Form\FormBuilder->buildForm(Object, Object)
Drupal\Core\Entity\EntityFormBuilder->getForm(Object)
Drupal\comment\Controller\CommentController->getReplyForm(Object, Object, 'field_comments', NULL)
call_user_func_array(Array, Array)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}()
call_user_func_array(Object, Array)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1)
Stack\StackedHttpKernel->handle(Object, 1, 1)
Drupal\Core\DrupalKernel->handle(Object)

After posting comment and clicking "Reply" /comment/reply/block_content/1/field_comments/7
Preview is broken again

The website encountered an unexpected error. Please try again later.

LogicException: The database connection is not serializable. This probably means you are serializing an object that has an indirect reference to the database connection. Adjust your code so that is not necessary. Alternatively, look at DependencySerializationTrait as a temporary solution. in Drupal\Core\Database\Connection->__sleep() (line 1433 of core/lib/Drupal/Core/Database/Connection.php).

serialize(Array)
Drupal\Component\Serialization\PhpSerialize::encode(Array)
Drupal\Core\KeyValueStore\DatabaseStorageExpirable->setWithExpire('form-1tWHxhgSCho58XOsZpVW7AGmhtw0YbYANa4BDEhE05E', Array, 21600)
Drupal\Core\Form\FormCache->setCache('form-1tWHxhgSCho58XOsZpVW7AGmhtw0YbYANa4BDEhE05E', Array, Object)
Drupal\Core\Form\FormBuilder->setCache('form-1tWHxhgSCho58XOsZpVW7AGmhtw0YbYANa4BDEhE05E', Array, Object)
Drupal\Core\Form\FormBuilder->rebuildForm('comment_block_form', Object, Array)
Drupal\Core\Form\FormBuilder->processForm('comment_block_form', Array, Object)
Drupal\Core\Form\FormBuilder->buildForm(Object, Object)
Drupal\Core\Entity\EntityFormBuilder->getForm(Object)
Drupal\comment\CommentLazyBuilders->renderForm('block_content', '1', 'field_comments', 'block')
call_user_func_array(Array, Array)
Drupal\Core\Render\Renderer->doRender(Array, 1)
Drupal\Core\Render\Renderer->render(Array, 1)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}()
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object)
Drupal\Core\Render\Renderer->renderPlain(Array)
Drupal\Core\Render\Renderer->renderPlaceholder('', Array)
Drupal\Core\Render\Renderer->replacePlaceholders(Array)
Drupal\Core\Render\Renderer->doRender(Array, 1)
Drupal\Core\Render\Renderer->render(Array, 1)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}()
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object)
Drupal\Core\Render\Renderer->renderRoot(Array)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->renderPlaceholders(Object)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments(Object)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond(Object, 'kernel.response', Object)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.response', Object)
Symfony\Component\HttpKernel\HttpKernel->filterResponse(Object, Object, 1)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1)
Stack\StackedHttpKernel->handle(Object, 1, 1)
Drupal\Core\DrupalKernel->handle(Object)

Let's see how much this breaks.

This feels at least a major bug and I guess considering I could not reproduce with about content translation that is it somehow related to that module.

I didn't even need to enable content translation/language at all to get the same error.

I'm getting this error when uploading images that are using entity reference and the media library. Add the images do not get uploaded. If I disable the Interface Translation module the error goes away and the images can be uploaded. I tried the patch but it didn't work for me.

I tried the steps to reproduce from the issue summary, and I can't trigger the error anymore, even with Content Translation enabled.

Note that the problem mentioned in #11 has its own issue: #2905198: The database connection is not serializable

I am going to reopen this issue as am getting the exact same issue when trying to preview a comment and have a multilingual site configured with an additional french language.

On Drupal 8.3.x

I have already applied the patch over at: #2893029: EntityType objects cannot be reliably serialized without DependencySerializationTrait still to no avail. Additionally have tried the patch above.

Will try to look into this further and provide more information.

I tested this on 9.4.x and was not able to reproduce this error, that same as @amateescu 5 years ago. I followed the steps given in the Issue Summary. I then enabled translation on the custom block type and the comment type. Then when translating the comment, I did get a WSOD.

InvalidArgumentException: Invalid translation language (it) specified. in Drupal\Core\Entity\ContentEntityBase->addTranslation() (line 956 of /var/www/html/core/lib/Drupal/Core/Entity/ContentEntityBase.php).

That is a different error than the one here so I will make a new issue for that.

Therefore, closing this as cannot reproduce. If you are experiencing this problem on a supported version of Drupal reopen the issue, by setting the status to 'Active', and provide complete steps to reproduce the issue (starting from "Install Drupal core").

Thanks!

new issue is #3282397: Logic Exception with preview button for block-comment

Relating this to a meta issue.