Broken special chars when Block unknown external resources

I've looked into this and I'm not sure if it's sufficiently dealing with all possible issues around encoding. As we spent quite some time on a similar issue in the past, let me post the way we've used to resolve this:

$content = mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8');
$document = \Drupal\Component\Utility\Html::load($content);

// Do all the manipulation here.

$html = HTML::serialize($document);
$html = str_replace('
', "\r", $html);
$html = mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8');

In the end, we seem to have covered everything related to non-ascii stuff. Leaveing the issue at NR as it's up to you whether you want to make use of this.

Had a hard time reproducing the issue and finally found out that it only happens when having twig.config.debug=true and it happens since Drupal added utf-8 icons to the twig debug comments, which must have been a recent update.

both, jan´s and jurgen´s code fix the display of the specialchars in the browser, but also both fail to encode the icons in the twig-debug-comments back correctly :(

According to #3488214 i set state to RTBC.

@sascha_meissner: The encoding back was missing at all :) I added this in last commit:

diff --git a/src/Utility/KlaroHelper.php b/src/Utility/KlaroHelper.php
index 7c54f58..336d418 100644
--- a/src/Utility/KlaroHelper.php
+++ b/src/Utility/KlaroHelper.php
@@ -805,6 +805,7 @@ class KlaroHelper {

     if ($complete_html) {
       $html = $dom->saveHTML();
+      $html = mb_decode_numericentity($html, [0x80, 0x10FFFF, 0, 0x1FFFFF], 'UTF-8');
     }
     else {
       $html = Html::serialize($dom);

Merged to dev. Thank you all for feedback and testing.

Automatically closed - issue fixed for 2 weeks with no activity.