lib/Twig/lib/Twig/Environment.php
public function initRuntime()
    {
        $this->runtimeInitialized = true;

        foreach ($this->getExtensions() as $name => $extension) {
            if (!$extension instanceof Twig_Extension_InitRuntimeInterface) {
                $m = new ReflectionMethod($extension, 'initRuntime');

                if ('Twig_Extension' !== $m->getDeclaringClass()->getName()) {
                    @trigger_error(sprintf('Defining the initRuntime() method in the "%s" extension is deprecated since version 1.23. Use the `needs_environment` option to get the Twig_Environment instance in filters, functions, or tests; or explicitly implement Twig_Extension_InitRuntimeInterface if needed (not recommended).', $name), E_USER_DEPRECATED);
                }
            }

            $extension->initRuntime($this);
        }
    }
public function initRuntime()
    {
        $this->runtimeInitialized = true;

        foreach ($this->getExtensions() as $name => $extension) {
            if (!$extension instanceof Twig_Extension_InitRuntimeInterface) {
                $m = new ReflectionMethod($extension, 'initRuntime');

                if ('Twig_Extension' !== $m->getDeclaringClass()->getName()) {
                    @trigger_error(sprintf('Defining the initRuntime() method in the "%s" extension is deprecated since version 1.23. Use the `needs_environment` option to get the Twig_Environment instance in filters, functions, or tests; or explicitly implement Twig_Extension_InitRuntimeInterface if needed (not recommended).', $name), E_USER_DEPRECATED);
                }
            }

            $extension->initRuntime($this);
        }
    }
Initializes the runtime environment.

@deprecated since 1.23 (to be removed in 2.0)