xray-core reverses finalmask.udp and refuses, at dial time, a mask that
dials its own socket (udphop) anywhere but the socket end: "incorrect
index". xray run -test still says Configuration OK, so the failure only
shows as a client that never connects.
UDPHopClientMaskFix turned a global subJsonFinalMask hop and a host hop
into udphop masks; the JSON subscription then appended both, leaving two
hoppers with the first one misplaced, and a host mask merged after a
global hop pushed it off the end too. A hand-ordered template outbound
or an imported fm= could carry the same order.
maskcompat.NormalizeUDPHop keeps the last-listed udphop alone at the end
of udp, and runs wherever a client finalmask is produced: each JSON
subscription endpoint, share-link fm=, the Go and frontend link
importers and the template outbound heal in GetXrayConfig. The JSON
subscription resolves competing hop ranges most specific first: a host
hop wins over the inbound's own, which wins over the global default.