Create alternative to Twig include function to improve Drupal integration

This is awesome and RTBC other than these nitpicks

1. +++ b/src/Template/TwigExtension.php
   @@ -0,0 +1,94 @@
   +namespace Drupal\components\Template;
   +use Drupal\Core\Render\RendererInterface;
   

   \n after namespace.

2. +++ b/src/Template/TwigExtension.php
   @@ -0,0 +1,94 @@
   +    return "components";
   

   single quotes

3. +++ b/src/Template/TwigNodeTheme.php
   @@ -0,0 +1,47 @@
   +  public function __construct(\Twig_Node_Expression $theme, \Twig_Node_Expression $variables = null, $ignore_missing = false, $lineno, $tag = null) {
   

   /false/FALSE/ and /null/NULL/

4. +++ b/src/Template/TwigNodeTheme.php
   @@ -0,0 +1,47 @@
   +      array('theme' => $theme, 'variables' => $variables),
   +      array('ignore_missing' => (bool) $ignore_missing),
   

   short array

5. +++ b/src/Template/TwigNodeTheme.php
   @@ -0,0 +1,47 @@
   +    if ($this->getAttribute('ignore_missing')) {
   +      $compiler->outdent()
   +        ->write("} catch (Twig_Error_Loader \$e) {\n")
   +        ->indent()
   

   Probably don't need this feature now.

6. +++ b/src/Template/TwigThemeTokenParser.php
   @@ -0,0 +1,61 @@
   + *      'items: [],
   

   missing single quote after 'items'

+++ b/src/Template/TwigNodeTheme.php
@@ -0,0 +1,47 @@
+    $compiler->write('echo ')
+      ->subcompile(new \Twig_Node_Expression_Function('theme', new \Twig_Node([$this->getNode('theme'), $this->getNode('variables')]), $this->getLine()))
+      ->raw("; \n");

It might be better to use a Twig_Node_Print unless we are 100% sure that we do not want to pass this through auto-escape, which might be true.

Nice work! - Looks great!

RTBC - Looks good to me then! :)

I looked at this patch very carefully, and this looks like a fancy way to do a Twig include, right?

In vanilla Twig, you can use a theme hook's template with:

{% include "@THEMENAME/item_list.html.twig" with {
      items: [
        'Test',
        'Test2'
      ],
    }
 %}

But you can't use a Drupal theme hook suggestion (e.g. item_list__node) and none of the preprocess hooks or template suggestion hooks are called.

Using a suggestion in theme would work, right?

{%
    theme "item_list__node" with {
      items: [
        'Test',
        'Test2'
      ],
    }
%}

Are there any other reasons to use theme over include? Include would be faster if you don't need those Drupal-specific features.

We need some docs.

And we need some tests!

But I've committed this patch in the meantime. Really good work!

Whats the status on this patch? I think still allowing for override while supporting include like functionality is a great addition.

Would using the theme call, does it also retain the caching metadata (from #cache render array)?
The reason I ask is that we've recently started encountering this issue:
Allow explicit bubbling of cacheability metadata inside Twig template (when accessing data from instead of rendering render arrays)

Another question, the theme looks similar to twigs include, but wouldn't it then also make sense to have one that works similar to twigs embed, so that we can override twig blocks within the embed?

I'm thinking of changing how the theme() function works. (Not how the theme tag works.)

#3082816: Make theme() function return render array could use some reviews.

I created a bunch of child issues with justifications for each change I wanted to make to this work. They are all completed now.

1. The theme tag has been removed because it is unsemantic. See #3090458: Remove theme tag
2. The theme() function returns a render array because core already renders array printed with {{ }}. And we can now apply filters to the raw render array (including the render filter if you really want a string). See #3082816: Make theme() function return render array
3. The theme() function has properly named arguments now. See #3090506: Improve named arguments of theme function

This is how the function works now:

{{ theme("card", {
    title: label,
    text: body,
  }
) }}

With Twig's new named arguments, you could also call that function like this:

{{ theme(
  hook = "card",
  variables = {
    title: label,
    text: body,
  }
) }}

Or like this:

{{ theme("card",
  variables = {
    title: label,
    text: body,
  }
) }}

I also kick-started the discussion in the core issue today by posting a patch, so if we want to discuss implementation details, it's probably best to do that there: #2818121: Create alternative to Twig include function to improve Drupal integration

Updated title to match core issue.

With #3091827: Use variadic arguments for template function and #3091775: Rename theme Twig function to be called 'template()', the latest version of this is now:

{{
  template("item-list.html.twig",
    title = "Animals not yet in Drupal core"
    items = ["lemur", "weasel", "honey badger"],
  )
}}

The template() function also accepts as its first argument: "item-list" or "item_list" or "item_list__node".

I think this can be closed now again or is there more to do?

This function is now documented at https://www.drupal.org/docs/contributed-modules/components/twig-function...