Comment forms are not displaying anymore

PR: https://github.com/drupal-media/entity_embed/pull/105

No clue whether switching to drupal_render_root() is the correct fix or not, but if it is, might be worth a comment about why this requires a drupal_render_root(), as IIRC drupal_render_root() is supposed to be the exception.

Might also be good to have @Wim Leers chime on this issue ?

Also, the bug is porobably not that much that comment forms are not displayed anymore (that in itself is not a really important feature ?), but more generally that cache placeholders are not replaced (which could be much more annoying for other stuff besides comment forms) ?

I found this at https://github.com/drupal-media/entity_embed/pull/105, I commented there, confirming that you want to use drupal_render_root().

Actually, it's not quite that simple anymore because we introduced safeguards to protect users from shooting themselves into the foot, which also prevents the suggested solution from working (and hence also the Travis testbot fails). We're working on adding an API to support this over at #2382667: #post_render_callback's that result from other #post_render_calback are not processed .

#2382667: #post_render_callback's that result from other #post_render_calback are not processed has now been committed; this change should no longer be necessary, it should all be working fine with the current entity_embed code against 8.x HEAD! :)