Field groups are not copied when cloning display

I can confirm indeed the variable is never defined!

So it will always be unset here without the fix:

if (!isset($destination_bundle_field_names[$child_field])) {
  unset($group_settings['children'][$index]);
}

Where I'm not sure is, if the $destination_bundle_field_names = $destination_display->getComponents(); should be inside the field_groups condition?

So I guess a maintainer will be able to answer this quickly and fix the clear bug. I won't set this RTBC, because I'm not deep enough into this here.

Setting priority to major as this is a clear code bug which breaks expected (and existing) functionality (and seems easy to solve, once a maintainer has a short look).

Don't kill me ;) ;)

+++ b/src/DisplayCloner.php
@@ -113,6 +113,8 @@ class DisplayCloner {
+    $destination_bundle_field_names = $destination_display->getComponents();

getComponents() does not return field names!

Just ran into this again, so I'll try to place this on our agenda.

I can confirm that the patch fixes the issue! Very weird, that the variable declaration of

$destination_bundle_field_names

was somehow removed.

I applied @holo96's patch as an MR changed the point of initialization and renamed the variable, please review!

EDIT: Just saw, that a couple of auto formatting changes were committed as well, hope that's fine.

Thank you @Grevil, that's indeed a crazy reason for the bug ;D

I think the fixes are okay, as it's not too many. RTBC! Would be great to have this fixed and Field groups support back again!

Hello, thanks for the work.
One missing thing. The code is not taking care of nested field groups.
As far as this is a 1 Year + RTBC issue, I think I can propose this :

         foreach ($group_settings['children'] as $index => $child_field) {
-          if (!isset($destination_bundle_field_names[$child_field])) {
+          if (!isset($field_group_settings[$child_field]) && !isset($destination_display_components[$child_field])) {
             unset($group_settings['children'][$index]);
           }
         }

I can update the branch if modification is OK for you.

I also would like to suggest the ability to choose whether or not the user wants to copy empty groups.

@mattlc, feel free to modify the MR!