Issue #3303086: CKEditor does not work when big_pipe is used

src/EventSubscriber/CoreCspSubscriber.php

@@ -85,8 +85,14 @@ class CoreCspSubscriber implements EventSubscriberInterface {
       // applied to calling page.
       $quickedit = in_array('quickedit/quickedit', $libraries) && $this->moduleHandler->moduleExists('ckeditor');
 
+      // As Big Pipe can display forms later on the page, the CKEditor library
+      // may not be detected on main page response.
+      $big_pipe = in_array('big_pipe/big_pipe', $libraries)
+        && $this->moduleHandler->moduleExists('big_pipe')
+        && $this->moduleHandler->moduleExists('ckeditor');
+
       // CKEditor requires script attribute on interface buttons.
-      if (in_array('core/ckeditor', $libraries) || $quickedit) {
+      if (in_array('core/ckeditor', $libraries) || $quickedit || $big_pipe) {
         $policy->fallbackAwareAppendIfEnabled('script-src-elem', []);
         $policy->fallbackAwareAppendIfEnabled('script-src', [Csp::POLICY_UNSAFE_INLINE]);
         $policy->fallbackAwareAppendIfEnabled('script-src-attr', [Csp::POLICY_UNSAFE_INLINE]);
@@ -94,7 +100,7 @@ class CoreCspSubscriber implements EventSubscriberInterface {
 
       // Inline style element is added by ckeditor.off-canvas-css-reset.js.
       // @see https://www.drupal.org/project/drupal/issues/2952390
-      if (in_array('ckeditor/drupal.ckeditor', $libraries) || $quickedit) {
+      if (in_array('ckeditor/drupal.ckeditor', $libraries) || $quickedit || $big_pipe) {
         $policy->fallbackAwareAppendIfEnabled('style-src', [Csp::POLICY_UNSAFE_INLINE]);
         $policy->fallbackAwareAppendIfEnabled('style-src-attr', [Csp::POLICY_UNSAFE_INLINE]);
         $policy->fallbackAwareAppendIfEnabled('style-src-elem', [Csp::POLICY_UNSAFE_INLINE]);