template extend not working if suppressTemplateError is set to true

Question

If I set

'suppressTemplateErrors' => true 

in the config/general.php

This (templates/_pages/_entry.twig):

{% extends [
'_pages/'~entry.slug|default,
"_pages/" ~ entry.type|default,
"_pages/default"
] %}

Gets me a blank page, since apparently it is seen as a mistake, and the execution of the twig template is stopped. However, when suppressTemplateErrors is set to false, there is no problem. the code is supposed to search for a template with the name of an entry slug, if that doesn't exist look for one with the name of the type, and if that doesn't exist, load the default template.

Logs (web.log):

2017-12-26 15:54:02 [::1][1][-][error][craft\web\twig\TemplateLoaderException] craft\web\twig\TemplateLoaderException: Coud not find template “_pages/about” . in /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/twig/TemplateLoader.php:125
Stack trace:
#0 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/twig/TemplateLoader.php(76): craft\web\twig\TemplateLoader->_resolveTemplate('_pages/about')
#1 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Environment.php(270): craft\web\twig\TemplateLoader->getCacheKey('_pages/about')
#2 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Environment.php(350): Twig_Environment->getTemplateClass('_pages/about')
#3 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/twig/Environment.php(30): Twig_Environment->loadTemplate('_pages/about', NULL)
#4 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Environment.php(478): craft\web\twig\Environment->loadTemplate('_pages/about')
#5 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Template.php(318): Twig_Environment->resolveTemplate(Array)
#6 /Users/username/Code/mywebsite/storage/runtime/compiled_templates/74/74f99748b2c43647e59f94561c58e670362eb7351e4ca94b81c3fcb1a4265158.php(10): Twig_Template->loadTemplate(Array, '_pages/_entry', 2)
#7 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Template.php(99): __TwigTemplate_49b39b86eb9a0dbc650dce81e0d17fe48175bd75d54e21236890fb8d13a20492->doGetParent(Array)
#8 /Users/username/Code/mywebsite/storage/runtime/compiled_templates/74/74f99748b2c43647e59f94561c58e670362eb7351e4ca94b81c3fcb1a4265158.php(16): Twig_Template->getParent(Array)
#9 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Template.php(389): __TwigTemplate_49b39b86eb9a0dbc650dce81e0d17fe48175bd75d54e21236890fb8d13a20492->doDisplay(Array, Array)
#10 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/twig/Template.php(51): Twig_Template->displayWithErrorHandling(Array, Array)
#11 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Template.php(366): craft\web\twig\Template->displayWithErrorHandling(Array, Array)
#12 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/twig/Template.php(32): Twig_Template->display(Array, Array)
#13 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Template.php(374): craft\web\twig\Template->display(Array)
#14 /Users/username/Code/mywebsite/vendor/twig/twig/lib/Twig/Environment.php(289): Twig_Template->render(Array)
#15 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/View.php(292): Twig_Environment->render('_pages/_entry', Array)
#16 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/View.php(340): craft\web\View->renderTemplate('_pages/_entry', Array)
#17 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/Controller.php(121): craft\web\View->renderPageTemplate('_pages/_entry', Array)
#18 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/controllers/TemplatesController.php(79): craft\web\Controller->renderTemplate('_pages/_entry', Array)
#19 [internal function]: craft\controllers\TemplatesController->actionRender('_pages/_entry', Array)
#20 /Users/username/Code/mywebsite/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#21 /Users/username/Code/mywebsite/vendor/yiisoft/yii2/base/Controller.php(157): yii\base\InlineAction->runWithParams(Array)
#22 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/Controller.php(80): yii\base\Controller->runAction('render', Array)
#23 /Users/username/Code/mywebsite/vendor/yiisoft/yii2/base/Module.php(528): craft\web\Controller->runAction('render', Array)
#24 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/Application.php(242): yii\base\Module->runAction('templates/rende...', Array)
#25 /Users/username/Code/mywebsite/vendor/yiisoft/yii2/web/Application.php(103): craft\web\Application->runAction('templates/rende...', Array)
#26 /Users/username/Code/mywebsite/vendor/craftcms/cms/src/web/Application.php(207): yii\web\Application->handleRequest(Object(craft\web\Request))
#27 /Users/username/Code/mywebsite/vendor/yiisoft/yii2/base/Application.php(386): craft\web\Application->handleRequest(Object(craft\web\Request))
#28 /Users/username/Code/mywebsite/www/index.php(35): yii\base\Application->run()
#29 {main}

Answer 1

So just as an information architecture kind of thing, you might want to have just one _layout.twig that all of your entry types extends, and just include various {% block %} tags in the right places for the templates to fill in.

That way, if you make major changes to the abstract pages (say, adding meta info, or changing JavaScript that's loaded site-wide, etc.) you don't have to make those changes in a number of places.

You can also leverage include and embed and you'll likely end up with a more manageable template hierarchy in the end.

That said, the problem you're having is that it's hitting this code block:

```

public function loadTemplate($name, $index = null)
{
    try
    {
        return parent::loadTemplate($name, $index);
    }
    catch (\Twig_Error $e)
    {
        if (craft()->config->get('suppressTemplateErrors'))
        {
            // Just log it and return an empty template
            craft()->errorHandler->logException($e);

            $twig = craft()->templates->getTwig('Twig_Loader_String');
            return $twig->loadTemplate('');
        }
        else
        {
            throw $e;
        }
    }
}

```

So while it normally would throw an exception, which Twig handles and then moves on to try the next template in the array you've passed it, with suppressTemplateErrors => true it just immediately returns an empty template.

You can file a bug report if you like, because this does appear to short-circuit the normal Twig fallback mechanism for template rendering, but I'd honestly re-examine how you're doing things. Depending on suppressing template errors for the site to work feels wrong.