TemplateLoader 500 error

JuliusSu

Hi everyone, we love Flarum and use it to run our discussion board of teachers from LA Unified. It has been invaluable during this time of remote learning.

Today I was adjusting some settings with the FoF upload extension, and Flarum stopped working. Logging in gave me the error: "An error occurred while trying to load this page."

I looked into the logs and saw the following stack trace:

[2020-05-05 20:59:48] production.ERROR: TypeError: Argument 1 passed to s9e\TextFormatter\Configurator\Helpers\TemplateLoader::innerXML() must be an instance of DOMElement, null given, called in /home/prod/flarum/vendor/s9e/text-formatter/src/Configurator/Helpers/TemplateLoader.php on line 79 and defined in /home/prod/flarum/vendor/s9e/text-formatter/src/Configurator/Helpers/TemplateLoader.php:30
Stack trace:
#0 /home/prod/flarum/vendor/s9e/text-formatter/src/Configurator/Helpers/TemplateLoader.php(79): s9e\TextFormatter\Configurator\Helpers\TemplateLoader::innerXML(NULL)
#1 /home/prod/flarum/vendor/s9e/text-formatter/src/Plugins/Emoticons/Configurator/EmoticonCollection.php(31): s9e\TextFormatter\Configurator\Helpers\TemplateLoader::save(Object(DOMDocument))
#2 /home/prod/flarum/vendor/s9e/text-formatter/src/Configurator/Collections/NormalizedCollection.php(217): s9e\TextFormatter\Plugins\Emoticons\Configurator\EmoticonCollection->normalizeValue('\xF0\x9F\x99\x82')
#3 /home/prod/flarum/vendor/s9e/text-formatter/src/Configurator/Collections/NormalizedCollection.php(135): s9e\TextFormatter\Configurator\Collections\NormalizedCollection->set('🙂', '\xF0\x9F\x99\x82')
#4 [internal function]: s9e\TextFormatter\Configurator\Collections\NormalizedCollection->add('🙂', '\xF0\x9F\x99\x82')
#5 /home/prod/flarum/vendor/s9e/text-formatter/src/Configurator/Traits/CollectionProxy.php(38): call_user_func_array(Array, Array)
#6 /home/prod/flarum/vendor/flarum/emoji/extend.php(20): s9e\TextFormatter\Plugins\Emoticons\Configurator->call('add', Array)
#7 /home/prod/flarum/vendor/flarum/core/src/Extend/Formatter.php(42): Flarum\Extension\Extension->{closure}(Object(s9e\TextFormatter\Configurator))
#8 /home/prod/flarum/vendor/illuminate/events/Dispatcher.php(360): Flarum\Extend\Formatter->Flarum\Extend{closure}(Object(Flarum\Formatter\Event\Configuring))
#9 /home/prod/flarum/vendor/illuminate/events/Dispatcher.php(209): Illuminate\Events\Dispatcher->Illuminate\Events{closure}('Flarum\Formatte...', Array)
#10 /home/prod/flarum/vendor/flarum/core/src/Formatter/Formatter.php(125): Illuminate\Events\Dispatcher->dispatch('Flarum\Formatte...')
#11 /home/prod/flarum/vendor/flarum/core/src/Formatter/Formatter.php(156): Flarum\Formatter\Formatter->getConfigurator()
#12 /home/prod/flarum/vendor/illuminate/cache/Repository.php(375): Flarum\Formatter\Formatter->Flarum\Formatter{closure}()
#13 /home/prod/flarum/vendor/flarum/core/src/Formatter/Formatter.php(157): Illuminate\Cache\Repository->rememberForever('flarum.formatte...', Object(Closure))
#14 /home/prod/flarum/vendor/flarum/core/src/Formatter/Formatter.php(200): Flarum\Formatter\Formatter->getComponent('js')
#15 /home/prod/flarum/vendor/flarum/core/src/Forum/ForumServiceProvider.php(103): Flarum\Formatter\Formatter->getJs()
#16 [internal function]: Flarum\Forum\ForumServiceProvider->Flarum\Forum{closure}()
#17 /home/prod/flarum/vendor/flarum/core/src/Frontend/Compiler/Source/StringSource.php(35): call_user_func(Object(Closure))
#18 /home/prod/flarum/vendor/flarum/core/src/Frontend/Compiler/Source/StringSource.php(46): Flarum\Frontend\Compiler\Source\StringSource->getContent()
#19 /home/prod/flarum/vendor/flarum/core/src/Frontend/Compiler/RevisionCompiler.php(239): Flarum\Frontend\Compiler\Source\StringSource->getCacheDifferentiator()
#20 /home/prod/flarum/vendor/flarum/core/src/Frontend/Compiler/RevisionCompiler.php(73): Flarum\Frontend\Compiler\RevisionCompiler->calculateRevision(Array)
#21 /home/prod/flarum/vendor/flarum/core/src/Frontend/Compiler/RevisionCompiler.php(125): Flarum\Frontend\Compiler\RevisionCompiler->commit()
#22 /home/prod/flarum/vendor/flarum/core/src/Frontend/Content/Assets.php(69): Flarum\Frontend\Compiler\RevisionCompiler->getUrl()
#23 [internal function]: Flarum\Frontend\Content\Assets->Flarum\Frontend\Content{closure}(Object(Flarum\Frontend\Compiler\JsCompiler))
#24 /home/prod/flarum/vendor/flarum/core/src/Frontend/Content/Assets.php(68): array_map(Object(Closure), Array)
#25 /home/prod/flarum/vendor/flarum/core/src/Frontend/Content/Assets.php(51): Flarum\Frontend\Content\Assets->getUrls(Array)
#26 /home/prod/flarum/vendor/flarum/core/src/Frontend/Frontend.php(63): Flarum\Frontend\Content\Assets->invoke(Object(Flarum\Frontend\Document), Object(Laminas\Diactoros\ServerRequest))
#27 /home/prod/flarum/vendor/flarum/core/src/Frontend/Frontend.php(55): Flarum\Frontend\Frontend->populate(Object(Flarum\Frontend\Document), Object(Laminas\Diactoros\ServerRequest))
#28 /home/prod/flarum/vendor/flarum/core/src/Frontend/Controller.php(32): Flarum\Frontend\Frontend->document(Object(Laminas\Diactoros\ServerRequest))
#29 /home/prod/flarum/vendor/flarum/core/src/Http/RouteHandlerFactory.php(38): Flarum\Frontend\Controller->handle(Object(Laminas\Diactoros\ServerRequest))
#30 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/DispatchRoute.php(65): Flarum\Http\RouteHandlerFactory->Flarum\Http{closure}(Object(Laminas\Diactoros\ServerRequest), Array)
#31 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\DispatchRoute->process(Object(Laminas\Diactoros\ServerRequest), Object(Closure))
#32 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/ShareErrorsFromSession.php(56): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#33 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ShareErrorsFromSession->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#34 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/SetLocale.php(50): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#35 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\SetLocale->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#36 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/CheckCsrfToken.php(23): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#37 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\CheckCsrfToken->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#38 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/AuthenticateWithSession.php(32): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#39 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\AuthenticateWithSession->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#40 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/RememberFromCookie.php(51): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#41 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\RememberFromCookie->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#42 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/StartSession.php(61): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#43 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\StartSession->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#44 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/CollectGarbage.php(46): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#45 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\CollectGarbage->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#46 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/ParseJsonBody.php(28): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#47 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\ParseJsonBody->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#48 /home/prod/flarum/vendor/flarum/core/src/Http/Middleware/HandleErrors.php(57): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#49 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Flarum\Http\Middleware\HandleErrors->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#50 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(84): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#51 /home/prod/flarum/vendor/middlewares/request-handler/src/RequestHandler.php(84): Laminas\Stratigility\MiddlewarePipe->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#52 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\RequestHandler->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#53 /home/prod/flarum/vendor/middlewares/base-path-router/src/BasePathRouter.php(97): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#54 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\BasePathRouter->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#55 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Middleware/OriginalMessages.php(42): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#56 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Laminas\Stratigility\Middleware\OriginalMessages->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#57 /home/prod/flarum/vendor/middlewares/base-path/src/BasePath.php(53): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#58 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/Next.php(61): Middlewares\BasePath->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\Next))
#59 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(84): Laminas\Stratigility\Next->handle(Object(Laminas\Diactoros\ServerRequest))
#60 /home/prod/flarum/vendor/laminas/laminas-stratigility/src/MiddlewarePipe.php(73): Laminas\Stratigility\MiddlewarePipe->process(Object(Laminas\Diactoros\ServerRequest), Object(Laminas\Stratigility\EmptyPipelineHandler))
#61 /home/prod/flarum/vendor/laminas/laminas-httphandlerrunner/src/RequestHandlerRunner.php(96): Laminas\Stratigility\MiddlewarePipe->handle(Object(Laminas\Diactoros\ServerRequest))
#62 /home/prod/flarum/vendor/flarum/core/src/Http/Server.php(42): Laminas\HttpHandlerRunner\RequestHandlerRunner->run()
#63 /home/prod/flarum/public/index.php(26): Flarum\Http\Server->listen()
#64 {main}

I have tried the following to fix the error:

clearing the PHP cache
uninstalling and reinstalling FOF/upload extension
enabling and disabling the FOF/upload extension

Nothing works and the error persists. I saw a similar error reported on the discussion board a couple of years back, but it looks like it was never resolved. The user gave up and switched to another software platform. I definitely do not want to do this. Our users love Flarum and I really want to fix this error so they can get back to posting. Can anyone help me?

askvortsov

Hi JuliusSu! Great to hear you're enjoying Flarum! Could you share the output of your php flarum infocommand?

Also, looking at a relevant github issue, one thing that has been suggested in the past is trying various combinations of PHP and libxml2, or directly deleting the text formatter cache via rm -rf storage/cache/textformatter/*. Could you try these and say if anything works?

JuliusSu

askvortsov Hello! Here is the output of php flarum info. I left debug on.

I tried deleting the text formatter cache via rm -rf storage/cache/textformatter/*. and it does not help.

Thanks!

JuliusSu

I just reinstalled Flarum from scratch while keeping the database the same, and am still getting the same error. Did not install any extensions this time.

JuliusSu

JuliusSu I also tried starting again from an empty database and the error persists. Very strange! it was working yesterday.

askvortsov

You mentioned that this happened spontaneously when trying to change FoF/Upload settings? Also, Is trying to change the PHP version or the libxml version an option?

@JoshyPHP, by any chance, is this something you've seen recently in other use cases of text formatter?

JuliusSu

I just tried updating libxml2 to v2.9.1, but the error still seems to persist.

JoshyPHP

Yes, that's something that I've seen pop up on some phpBB installs. The issue is that $documentElement is null even though that's not technically possible. It can be fixed by recompiling PHP and/or libxml2, using a different PHP binary, linking to a different libxml2 or possibly disabling Xdebug.

I don't know what the core of the issue is but from what I can tell it's related to the way the PHP binary links to the libxml2 binary.

Also this: https://magento.stackexchange.com/questions/282703/undefined-property-domdocumentdocumentelement-in-magento-2

JuliusSu

I fixed it!!! updating libxml2 did not do anything, but upgrading from PHP 7.3.17 to 7.4.5 did the trick.

The issue occurred with a fresh installation, an empty database, and no extensions, so it looks like it was something caused by the old version of PHP.

Thank you for your fast and responsive support! Now our teachers can go back to posting about their lessons 🙂 appreciate your help.