Fix for MariaDB re Issue #119

[alexgw]

As suggested by https://github.com/sebastiencyr on #119

[puikinsh]

Thank you @alexgw — and @sebastiencyr for the original analysis on #119! 🙏

You were right: refresh() re-ranked rows using a MySQL user variable (@row_number) inside a derived table, and that evaluation order is undefined on MariaDB / MySQL 8, so menu_order could get scrambled when the sequence was re-normalized after gaps appeared.

This is fixed in 2.7.1 (just released to WordPress.org). Rather than the UNION ALL approach — which would build one SELECT per post and could get very large on big post types — we re-number deterministically in a small PHP loop, which is DB-agnostic and avoids user variables entirely:

$ordered_ids = $wpdb->get_col( $wpdb->prepare(
    "SELECT ID FROM $wpdb->posts
     WHERE post_type = %s AND post_status IN ('publish','pending','draft','private','future')
     ORDER BY menu_order ASC",
    $object
) );
foreach ( $ordered_ids as $position => $id ) {
    $wpdb->update( $wpdb->posts, [ 'menu_order' => $position + 1 ], [ 'ID' => (int) $id ] );
}

You're both credited in the changelog. Closing as resolved in 2.7.1 — thanks again for chasing this down!