In PHP 8.1 I am receiving the error below when using CActiveForm checkbox field, when the CFormModel model attribute has a default 'null' value as defined.
"strcmp(): Passing null to parameter #2 ($string2) of type string is deprecated"
The 'null' value is passed to the checkBoxList() method as the second argument variable $select. A null value is not allowed in PHP 8.1 in strcmp(). An additional condition check for !empty() on the $select variable will prevent this error, as well as support the remaining variable types for a string or array.
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