Default values for checkboxes always selected when editing or viewing

I am not able to reproduce this issue using the attached webform. Please provide an example webform or more information.

If I uncheck all checkboxes and submit the webform the submitted values are OK (Submitted values are: checkboxes: { }) Thats fine.
But if review the results of this submission (HTML, Table, Plain text) or edit the submission again, the field values are displayed as "checkboxes one, two, three".
Only viewing the results as YAML shows it correct ("data: { }")

Thanks for explaining how to reproduce the issue. This is a major issue because the displayed data is wrong.

This issue also impacts multiple select menus.

checkboxes:
  '#type': checkboxes
  '#title': checkboxes
  '#options':
    one: one
    two: two
    three: three
  '#default_value':
    - one
    - two
    - three
select:
  '#type': select
  '#title': select
  '#multiple': true
  '#options':
    one: one
    two: two
    three: three
  '#default_value':
    - one
    - two
    - three

The attached patch only partially solves the issue of not displaying the default values.

I am unsure how to handle the default value when editing a submission.

The attached patch goes after the root cause where a submissions empty multiple-value elements are returned as NULL and not an empty array (i.e., []).

There are performance implications for the patch from #7, which could be mitigated with a caching strategy.

The last submitted patch, 7: 3340590-7.patch, failed testing. View results →

The last submitted patch, 9: 3340590-9.patch, failed testing. View results →

The last submitted patch, 13: 3340590-13.patch, failed testing. View results →

Automatically closed - issue fixed for 2 weeks with no activity.