Settings sanitize callback - $option arg is not available

[dashaluna]

If you register a setting and specify a sanitize callback, the option name argument is not available in the callback function.

See wp-includes/formatting.php line 3432 - where WordPress applys the santiization filters.

    $value = apply_filters( "sanitize_option_{$option}", $value, $option );

It passes as second arg of $option, but when registering as setting - the sanitization callback is added to this filter, but the number of accepted args is not specified when adding the filter.

[mattheu]

It turns out that this has been removed intentionally to maintain backwards compatability - see https://core.trac.wordpress.org/ticket/18914

[SergeyBiryukov]

Duplicate of #15335.