Twig_Error_Syntax: Unknown "template_from_string" function. Function became obsolete? - php

Question

I remember after composer updating I got this error, but previously it worked perfectly, and in comparing the packages versions I didn't find differences. I used it in this way in template:
{{ include(template_from_string(page.body)) }}
where "page" is entity object from controller. Current versions are:
symfony/symfony v2.8.15
twig/extensions v1.4.1
twig/twig v1.30.0
Also in config.yml:
twig:
debug: "%kernel.debug%"
strict_variables: "%kernel.debug%"
form_themes:
- 'AppBundle::Form/form_override.html.twig'
Now there is in vendor/twig/twig/lib/twig/Twig/Extension/StringLoader.php visually correct file, but seems it still not working. Full stacktrace:
[1] Twig_Error_Syntax: Unknown "template_from_string" function.
at n/a
in ProjectDir\src\AppBundle/Resources/views/Page.html.twig line 22
at Twig_ExpressionParser->getFunctionNodeClass('template_from_string', '22')
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 374
at Twig_ExpressionParser->getFunctionNode('template_from_string', '22')
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 162
at Twig_ExpressionParser->parsePrimaryExpression()
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 102
at Twig_ExpressionParser->getPrimary()
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 55
at Twig_ExpressionParser->parseExpression()
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 520
at Twig_ExpressionParser->parseArguments(true)
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 373
at Twig_ExpressionParser->getFunctionNode('include', '22')
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 162
at Twig_ExpressionParser->parsePrimaryExpression()
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 102
at Twig_ExpressionParser->getPrimary()
in ProjectDir\vendor\twig\twig\lib\Twig\ExpressionParser.php line 55
at Twig_ExpressionParser->parseExpression()
in ProjectDir\vendor\twig\twig\lib\Twig\Parser.php line 147
at Twig_Parser->subparse(array(object(Twig_TokenParser_Block), 'decideBlockEnd'), true)
in ProjectDir\vendor\twig\twig\lib\Twig\TokenParser\Block.php line 40
at Twig_TokenParser_Block->parse(object(Twig_Token))
in ProjectDir\vendor\twig\twig\lib\Twig\Parser.php line 190
at Twig_Parser->subparse(null, false)
in ProjectDir\vendor\twig\twig\lib\Twig\Parser.php line 103
at Twig_Parser->parse(object(Twig_TokenStream))
in ProjectDir\app\cache\dev\classes.php line 3415
at Twig_Environment->parse(object(Twig_TokenStream))
in ProjectDir\app\cache\dev\classes.php line 3443
at Twig_Environment->compileSource(object(Twig_Source))
in ProjectDir\app\cache\dev\classes.php line 3291
at Twig_Environment->loadTemplate('AppBundle::Page.html.twig')
in ProjectDir\vendor\symfony\symfony\src\Symfony\Bridge\Twig\TwigEngine.php line 126
at Symfony\Bridge\Twig\TwigEngine->load('AppBundle::Page.html.twig')
in ProjectDir\vendor\symfony\symfony\src\Symfony\Bridge\Twig\TwigEngine.php line 50
at Symfony\Bridge\Twig\TwigEngine->render('AppBundle::Page.html.twig', array('page' => object(Page), 'ads' => array(object(VertBanner), object(VertBanner)), 'slug' => 'direktor'))
in ProjectDir\vendor\symfony\symfony\src\Symfony\Bundle\TwigBundle\TwigEngine.php line 72
at Symfony\Bundle\TwigBundle\TwigEngine->render('AppBundle::Page.html.twig', array('page' => object(Page), 'ads' => array(object(VertBanner), object(VertBanner)), 'slug' => 'direktor'))
in ProjectDir\vendor\symfony\symfony\src\Symfony\Bundle\TwigBundle\TwigEngine.php line 103
at Symfony\Bundle\TwigBundle\TwigEngine->renderResponse('AppBundle::Page.html.twig', array('page' => object(Page), 'ads' => array(object(VertBanner), object(VertBanner)), 'slug' => 'direktor'), null)
in ProjectDir\vendor\symfony\symfony\src\Symfony\Bundle\FrameworkBundle\Controller\Controller.php line 185
at Symfony\Bundle\FrameworkBundle\Controller\Controller->render('AppBundle::Page.html.twig', array('page' => object(Page), 'ads' => array(object(VertBanner), object(VertBanner)), 'slug' => 'direktor'))
in ProjectDir\src\AppBundle\Controller\PageController.php line 35
at AppBundle\Controller\PageController->getPageAction('direktor')
in line
at call_user_func_array(array(object(PageController), 'getPageAction'), array('direktor'))
in ProjectDir\vendor\symfony\symfony\src\Symfony\Component\HttpKernel\HttpKernel.php line 144
at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), '1')
in ProjectDir\vendor\symfony\symfony\src\Symfony\Component\HttpKernel\HttpKernel.php line 64
at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), '1', true)
in ProjectDir\vendor\symfony\symfony\src\Symfony\Component\HttpKernel\DependencyInjection\ContainerAwareHttpKernel.php line 69
at Symfony\Component\HttpKernel\DependencyInjection\ContainerAwareHttpKernel->handle(object(Request), '1', true)
in ProjectDir\vendor\symfony\symfony\src\Symfony\Component\HttpKernel\Kernel.php line 185
at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
in ProjectDir\web\app_dev.php line 28
at require('ProjectDir\web\app_dev.php')
in ProjectDir\vendor\symfony\symfony\src\Symfony\Bundle\FrameworkBundle\Resources\config\router_dev.php line 40

Answer 1

You must let the Service Container know about your Twig Extension:
# app/config/services.yml
acme.twig.extension.loader:
class: Twig_Extension_StringLoader
tags:
- { name: 'twig.extension' }
Symfony 4:
# config/services.yml
app.twig.extension.loader:
class: Twig\Extension\StringLoaderExtension
tags:
- { name: 'twig.extension' }

Answer 2

For symfony5 and twig3, the answer from here worked: Symfony 4: Add Twig_Extension_StringLoader
# config/services.yaml
services:
Twig\Extension\StringLoaderExtension:
As this is more easily findable in google, I'll add it here.