Default preview controller should not crash with config.action_controller.include_all_helpers = false (fixes #1654)

Author: triskweline

app/controllers/concerns/view_component/preview_actions.rb

@@ -14,7 +14,12 @@ module PreviewActions
 
       # Including helpers here ensures that we're loading the
       # latest version of helpers if code-reloading is enabled
-      helper :all if include_all_helpers
+      if include_all_helpers
+        helper :all
+      else
+        # Always provide the #view_source helper
+        helper PreviewHelper
+      end
     end
 
     def index

docs/CHANGELOG.md

@@ -26,6 +26,11 @@ nav_order: 5
 
     *Reegan Viljoen*
 
+* Fix a bug where component previews would crash with "undefined local variable or method `preview_source'"
+
+    *Henning Koch*
+
+
 ## 3.12.1
 
 * Ensure content is rendered correctly for forwarded slots.