When the premium-name lookup failed, isPremiumName fell back to any
cached answer, however old. An expired "free" is exactly the answer
that may have stopped being true: someone can buy the name after it
was last seen free. For as long as api.mojang.com kept failing (429,
5xx, a timeout), a third-party player holding that name kept it on
every reconnect, and the Velocity registry, keyed on the name, turned
its new owner away as already connected. A hostile source could drive
the host into Mojang's rate limit on purpose to hold names that way.
A failed lookup now always counts as taken, so the player is renamed
with the source's prefix. An expired "taken" already gave that answer,
so only the stale "free" case changes. The cost is cosmetic: during an
outage an ordinary third-party player may get a prefix they do not
need, and their data follows the UUID, not the name.
A new test gives the cache a free entry past its TTL and has Mojang
answer 429. It fails on the old fallback. The two comments that
described the fallback now describe the fail-closed rule.
flyemoji
e9f74f3f0f