I have tested this item ✅ successfully on a066d43

For my education can you please explain the changes regarding use statements.

Previously I was told that if its used only once in the file then it should be
class PlgFieldsMenuitem extends \Joomla\Component\Fields\Administrator\Plugin\FieldsPlugin

and not

use Joomla\Component\Fields\Administrator\Plugin\FieldsPlugin;
class PlgFieldsMenuitem extends FieldsPlugin

But you have changed this in the file

I have tested this item ✅ successfully on a066d43

Sorry but this is not the correct fix.

The custom field should work the same as the standard fields see https://docs.joomla.org/Menuitem_form_field_type

As you can see I missed adding the published option and just used the default

published (optional) determines whether all menu items are listed or only published menu items. If state is '0' then all menu items will be listed. If state is '1' then only published menu items will be listed. You also can use comma separated values like '1,2'.

Removing the ability to select an unpublished menu item severely limits the usability of this field ie you can not create links in advance of publishing the menu item

I have tested this item ? unsuccessfully on a066d43

For my education can you please explain the changes regarding use statements.

For me you always add namespaces to the list of use statements, so you have a complete overview of the namespaces you include.

Previously I was told that if its used only once in the file then it should be

I am not aware of such rule nor do I understand why it should be that way. The only time you could use the full path is when you have a naming conflict but even then namespaces can be aliased. If it is a rule, then it should be reverted.

Sorry but this is not the correct fix.

Fine, I am going to revert the custom field and we can apply proper fixes and get it ready for 4.3.

There are over 50 instances of
class xxxxxx extends \JoomlaXXXXXXXXXXXXXX

in fact almost all of those are for field plugins just like this one

but if you want to change that and always use namespaces then that is fine by me but then dont you also need to remove
* @phpcs:disable PSR1.Classes.ClassDeclaration.MissingNamespace

The problem must be in the parent groupedlistfield and not here as if you are using the usergroup list field then the exact same testing instructions do not produce the error

actually I misread part of this and you missed it in my comment

I read it as this pr removed the ability to SELECT an unpublished menu item which is what I said was desired.

Removing the ability to select an unpublished menu item severely limits the usability of this field ie you can not create links in advance of publishing the menu item

I see now that the check is only for the output of the link