Methods in the CLI class are registered using WP_CLI::add_command, passing array('WC\SmoothGenerator\CLI', 'method') as callbacks. This kind of callback is not supported in PHP 8 when the method is not static, as per the upgrading guide:
Removed ability to call non-static methods statically. Thus is_callable will fail when checking for a non-static method with a classname (must check with an object instance).
The fix consists of simply making these methods static, which semantically they are already anyway.
Methods in the
CLIclass are registered usingWP_CLI::add_command, passingarray('WC\SmoothGenerator\CLI', 'method')as callbacks. This kind of callback is not supported in PHP 8 when the method is not static, as per the upgrading guide:The fix consists of simply making these methods static, which semantically they are already anyway.