Implement TrustedCallbackInterface to fix deprecation notices

Thank you!

But perhaps it is too early. The required class is not there yet. When Drupal stable version reaches 8.9, and Blazy explicitly depends on D8.8, this can work.

Also you may want to remove the deprecated function blazy_test_pre_render altogether rather than keeping it.

Feel free to postpone it for future task. Also please update the related issue at Slick.

Thoughts?

Let's postpone this till June 3, 2020 or few months after 8.9 out. Otherwise this patch may kill 6K+ websites using D8.7 below (the current majority sites using Blazy 2.x as of this writing). Feel free to-reopen it once you think it is safe to apply it. Thanks!

Just a friendly reminder to myself:
Be sure to also update GridStack with the relevant patch accordingly before committing this!

Added special for easy tracking related issues.

Per a Slack discussion with Gábor Hojtsy regarding usage of D9 tags (Drupal 9, Drupal 9 compatibility, Drupal 9 readiness, etc.), "Drupal 9 compatibility" should be used for contributed projects that need updating and "Drupal 9" was the old tag for D8 issues before the D9 branch was ready. Doing tag cleanup here based on that discussion.

The latest RC7 has no longer worked for D8.7 by mistakes starting with this feature #3113089: Fix subclassing and stop overriding constructors in blazy\Plugin\Field\FieldFormatter\BlazyMediaFormatterBase.
The reason, Drupal 8 FormatterBase never implements ContainerFactoryPluginInterface till D8.8, and I missed reviewing it against D8.7.

While we can add a BC for D8.7 post RC7, however seeing this particular issue is far more crucial than BC, I thought we should move forward. D8.7 Blazy users can stick to RC6 till they have time to upgrade to D8.8.

Let's re-open this sooner than June 3, 2020 thanks to my oversight mistake. Doh.

+++ b/tests/modules/blazy_test/blazy_test.module
@@ -61,14 +62,8 @@ function blazy_test_blazy_alter(array &$image, array $settings = []) {
  */
 function blazy_test_pre_render($image) {
-  $settings = isset($image['#settings']) ? $image['#settings'] : [];
-
-  // Video's HREF points to external site, adds URL to local image.
-  if (!empty($settings['box_url']) && !empty($settings['embed_url'])) {
-    $image['#url_attributes']['data-box-url'] = $settings['box_url'];
-  }
-
-  return $image;
+  @trigger_error('blazy_test_pre_render() is deprecated in Drupal 8.8.0 and will be removed before Drupal 9.0.0. Use \Drupal\blazy\BlazyTestAlter::preRender() instead. See https://www.drupal.org/node/2966725', E_USER_DEPRECATED);
+  return BlazyTestAlter::preRender($image);
 }

The message doesn't really make sense as this is obviously not a core deprecation.

Probably makes sense if the maintainer defines if he wants to keep this for BC or just remove it. IMHO it would be fine to remove.

Also, the patch should raise the required version to "^8.8 || ^9" then, remove the core key and also the "(>= 8.6)" part from the drupal:media dependency.

We should be remove it and incorporate the rest of suggestions. Thank you.

Attached to move forward with D8.8+.
Let's see if any issue I am not aware of.

Thou shall not kill kittens, even by mistake. Thou shall move forward, though. Move on!

Any (side) issue and improvements may follow as always.
Committed with minor change. Thank you for contribution!