Remove references to hook_init()

Well, the init hooks in the theme engines aren't gone. One could argue they are poorly named, but they are called from _drupal_theme_initialize()

Updated patch.

Can we add a @see to _drupal_theme_initialize() ? That would be incredibly helpful.

See also the changes happening in #340723: Make modules and installation profiles only require .info.yml files, the passed argument is no longer a stdClass. But it's probably better to wait with this until that issue has been committed to avoid unnecessary conflicts/re-rolls.

hook_init() is part of the Theme Engine API — a crucial part even.

It would probably be best to establish documentation for this callback (not hook) in /core/modules/system/theme.api.php

At least, that is the API documentation file that documents all theme related callbacks and hooks. (I don't think we ever had proper API docs for theme engines.)

Closely related: #1685492: Convert theme engines into services

See also #1332068: ENGINE_render_template() and ENGINE_extension() are undocumented

This is docs only so it's still viable for RC. Needs a reroll - phptemplate is gone but nyan_cat_init() is in :)

that's the reroll.

Patch seems ok to me. Thanks!

+++ b/core/modules/system/tests/themes/engines/nyan_cat/nyan_cat.engine
@@ -8,7 +8,10 @@
+ * @param stdClass $template

Shouldn't the type hint be on the Extension class?

Yeah and "Theme template object" doesn't seem right either anymore.

I have done the following changes

 /**
- * Implements hook_init().
+ * Includes .theme file, which contains functions to support theming.
+ *
+ * @param \Drupal\Core\Extension\Extension $theme
+ *   Theme template object.
  */

Theme template object still seems wrong, it's an extension object. So maybe something like "The theme extension object."?

Thanks.

@Cottser

I updated to

- * Implements hook_init().
+ * Includes .theme file, which contains functions to support theming.
+ *
+ * @param \Drupal\Core\Extension\Extension $theme
+ *   The theme extension object.

+++ b/core/modules/system/tests/themes/engines/nyan_cat/nyan_cat.engine
@@ -8,7 +8,10 @@
+ * Includes .theme file, which contains functions to support theming.

The wording could be just simply "Includes .theme file from themes." because I feel like the information where its being loaded is more important than information what .theme file is.

Done as stated by #21

Looks good for me! Thanks @snehi!

Hmmm... the twig_init function seems a bit pointless no?

Couldn't...

      if (function_exists($theme_engine . '_init')) {
        foreach ($active_theme->getBaseThemes() as $base) {
          call_user_func($theme_engine . '_init', $base->getExtension());
        }
        call_user_func($theme_engine . '_init', $active_theme->getExtension());
      }

be the following code instead...

  foreach ($active_theme->getBaseThemes() as $base) {
    $base->getExtension()->load();
  }
  $active_theme->getExtension()->load();

I think we should consider refactoring this as theme engine loading was some of the last work we did before RC.

Is there a case where the $theme_engine . '_init' function will be more complex?

@alexpott I think you are totally right. This is still RTBC as such but I've opened up a follow-up so that we can refactor the ENGINE_init to load.

Doubtful we can do that change in 8.0.1 as it's not a bug, but this one we can.

Committed/pushed to 8.1.x and cherry-picked to 8.0.x. Thanks!