GORM's struct-based Updates() silently skips nil pointer fields.
When SetNodeTags sets node.UserID = nil to transfer ownership to tags,
the in-memory NodeStore is correct but the database retains the old
user_id value. This causes tagged nodes to remain associated with the
original user in the database, preventing user deletion and risking
ON DELETE CASCADE destroying tagged nodes.
Add Select("*") before Omit() on all three node persistence paths
to force GORM to include all fields in the UPDATE statement, including
nil pointers. This is the same pattern already used in db/ip.go for
IPv4/IPv6 nil handling, and is documented GORM behavior:
db.Select("*").Omit("excluded").Updates(struct)
The three affected paths are:
- persistNodeToDB: used by SetNodeTags and MapRequest updates
- applyAuthNodeUpdate: used by re-authentication with --advertise-tags
- HandleNodeFromPreAuthKey: used by PAK re-registration
Fixes#3161
ccddeceeec