Pull Request for Issue #25785.

Summary of Changes

Currently, it is not possible to provide default value for Checkboxes and Multiple List custom fields. You would get the following error if you try to do that

Save failed with the following error: The default value is invalid

This PR just fixes that wrong validation.

Testing Instructions

1. Use Joomla 4.2
2. Test 1: Create a Checkboxes custom field. Set multiple default value for the field, uses comma to separate these values (For example value1,value2)
3. Test 2: Create a List custom field, set Multiple to Yes. Use a json string to set default values for the field (For example ["value1", "value2"]

Actual result BEFORE applying this Pull Request

When you try to set the field, you will get validation error:

Save failed with the following error: The default value is invalid

Expected result AFTER applying this Pull Request

No error. Field saved properly.

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed