pdf export: Parent table not found for table cell

[tipuraneo]

Describe the Bug

Hello,

I am running Bockstack v24.12 on Ubuntu 22.04.5 LTS with Apache/2.4.52 (Ubuntu) and PHP 8.1.2-1ubuntu2.2. During the pdf export of the chapter I get the following error in the laravel.log.

[2025-01-07 17:35:48] production.ERROR: Parent table not found for table cell {"exception":"[object] (Dompdf\\Exception(code: 0): Parent table not found for table cell at /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/TableCell.php:40)
[stacktrace]
#0 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\TableCell->reflow()
#1 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/TableRow.php(56): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#2 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\TableRow->reflow()
#3 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/TableRowGroup.php(50): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#4 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\TableRowGroup->reflow()
#5 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/Block.php(865): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#6 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\Block->reflow()
#7 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/Block.php(865): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#8 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\Block->reflow()
#9 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/Block.php(865): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#10 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\Block->reflow()
#11 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameReflower/Page.php(142): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#12 /var/www/bookstack/vendor/dompdf/dompdf/src/FrameDecorator/AbstractFrameDecorator.php(905): Dompdf\\FrameReflower\\Page->reflow()
#13 /var/www/bookstack/vendor/dompdf/dompdf/src/Dompdf.php(808): Dompdf\\FrameDecorator\\AbstractFrameDecorator->reflow()
#14 /var/www/bookstack/app/Exports/PdfGenerator.php(64): Dompdf\\Dompdf->render()
#15 /var/www/bookstack/app/Exports/PdfGenerator.php(26): BookStack\\Exports\\PdfGenerator->renderUsingDomPdf()
#16 /var/www/bookstack/app/Exports/ExportFormatter.php(162): BookStack\\Exports\\PdfGenerator->fromHtml()
#17 /var/www/bookstack/app/Exports/ExportFormatter.php(125): BookStack\\Exports\\ExportFormatter->htmlToPdf()
#18 /var/www/bookstack/app/Exports/Controllers/ChapterExportController.php(30): BookStack\\Exports\\ExportFormatter->chapterToPdf()
#19 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Controller.php(54): BookStack\\Exports\\Controllers\\ChapterExportController->pdf()
#20 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php(43): Illuminate\\Routing\\Controller->callAction()
#21 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Route.php(260): Illuminate\\Routing\\ControllerDispatcher->dispatch()
#22 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Route.php(205): Illuminate\\Routing\\Route->runController()
#23 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Router.php(806): Illuminate\\Routing\\Route->run()
#24 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(144): Illuminate\\Routing\\Router->Illuminate\\Routing\\{closure}()
#25 /var/www/bookstack/app/Http/Middleware/CheckUserHasPermission.php(25): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#26 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\CheckUserHasPermission->handle()
#27 /var/www/bookstack/app/Http/Middleware/Authenticate.php(23): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#28 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\Authenticate->handle()
#29 /var/www/bookstack/app/Http/Middleware/Localization.php(32): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#30 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\Localization->handle()
#31 /var/www/bookstack/app/Http/Middleware/RunThemeActions.php(26): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#32 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\RunThemeActions->handle()
#33 /var/www/bookstack/app/Http/Middleware/CheckEmailConfirmed.php(47): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#34 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\CheckEmailConfirmed->handle()
#35 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php(78): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#36 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Foundation\\Http\\Middleware\\VerifyCsrfToken->handle()
#37 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/View/Middleware/ShareErrorsFromSession.php(49): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#38 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\View\\Middleware\\ShareErrorsFromSession->handle()
#39 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(121): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#40 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php(64): Illuminate\\Session\\Middleware\\StartSession->handleStatefulRequest()
#41 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Session\\Middleware\\StartSession->handle()
#42 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/AddQueuedCookiesToResponse.php(37): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#43 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Cookie\\Middleware\\AddQueuedCookiesToResponse->handle()
#44 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Cookie/Middleware/EncryptCookies.php(67): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#45 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Cookie\\Middleware\\EncryptCookies->handle()
#46 /var/www/bookstack/app/Http/Middleware/ApplyCspRules.php(33): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#47 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\ApplyCspRules->handle()
#48 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(119): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#49 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Router.php(807): Illuminate\\Pipeline\\Pipeline->then()
#50 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Router.php(784): Illuminate\\Routing\\Router->runRouteWithinStack()
#51 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Router.php(748): Illuminate\\Routing\\Router->runRoute()
#52 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Routing/Router.php(737): Illuminate\\Routing\\Router->dispatchToRoute()
#53 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(200): Illuminate\\Routing\\Router->dispatch()
#54 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(144): Illuminate\\Foundation\\Http\\Kernel->Illuminate\\Foundation\\Http\\{closure}()
#55 /var/www/bookstack/app/Http/Middleware/PreventResponseCaching.php(21): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#56 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\PreventResponseCaching->handle()
#57 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Http/Middleware/TrustProxies.php(39): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#58 /var/www/bookstack/app/Http/Middleware/TrustProxies.php(41): Illuminate\\Http\\Middleware\\TrustProxies->handle()
#59 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): BookStack\\Http\\Middleware\\TrustProxies->handle()
#60 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php(21): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#61 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/TrimStrings.php(40): Illuminate\\Foundation\\Http\\Middleware\\TransformsRequest->handle()
#62 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Foundation\\Http\\Middleware\\TrimStrings->handle()
#63 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/ValidatePostSize.php(27): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#64 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Foundation\\Http\\Middleware\\ValidatePostSize->handle()
#65 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/PreventRequestsDuringMaintenance.php(99): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#66 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(183): Illuminate\\Foundation\\Http\\Middleware\\PreventRequestsDuringMaintenance->handle()
#67 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php(119): Illuminate\\Pipeline\\Pipeline->Illuminate\\Pipeline\\{closure}()
#68 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(175): Illuminate\\Pipeline\\Pipeline->then()
#69 /var/www/bookstack/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php(144): Illuminate\\Foundation\\Http\\Kernel->sendRequestThroughRouter()
#70 /var/www/bookstack/public/index.php(53): Illuminate\\Foundation\\Http\\Kernel->handle()
#71 {main}
"}

apache error.log does not give any hints. access.log says:

x.x.x.x - - [07/Jan/2025:17:49:51 +0100] "GET /books/moodle/chapter/interaktivitat-und-austausch/export/pdf HTTP/1.1" 500 22179 "https://kb.el.uni-leipzig.de/books/moodle/chapter/interaktivitat-und-austausch" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"

Error occurs with and without logged in user.
How can I fix it?

Kind Regards

Steps to Reproduce

1. navigate to Website
2. click on Export > PDF

Expected Behaviour

generating a pdf file and push it for download

Screenshots or Additional Context

Browser Details

Chrome

Exact BookStack Version

v24.12

[tipuraneo]

I was able to narrow down the issue to a single page. By creating a new page with a the simplest possible table could reproduce the issue:

<table id="bkmrk-%C2%A0">
<tbody>
<tr>
<td>&nbsp;</td>
</tr>
</tbody>
</table>