Backed Enum and serialization

Hi all, recently through Máté, I discovered that Backed Enum behaviour was changed for http_build_query in PHP8.4 see the github PR https://github.com/php/php-src/issues/15650 This change was never discussed on the mailing list and seems to have been prompt to align with a SOAP client serialization fix and to align with how BackedEnum are serialized using json_encode. Now I believe the PHP does some serialization elsewhere for instance when using fputcsv. My question is should Backed Enum also be handled differently in case of fputcsv ? IMHO if we want consistency in the PHP language the answer should be yes and have BackedEnum converted to their value (string or int) before serialization. Either way I believe a discussion about it should take place. My goal would be to have a clear rule on how Backed Enum is serialized across PHP regardless of the feature. I have not made any attempt at screening or searching for all serialization mechanisms in PHP but I presume they should all be listed and updated to follow the same rule for consistency. Best regards, Ignace