The protocol-4 cutover moved `link`'s PROTOCOL_VERSION, the overlay's
`overlay.toml` and this module's ingest — `guild.roster` and `guild.leave`
landed with the Teams cutover — but left both of this module's pin sites at 3.
A fresh install therefore came up speaking 3 to a protocol-4 sidecar, and a
sidecar answers a stale client with `409 protocol version mismatch` rather than
mis-parsing it. The failure is total and silent: every REST read fails, the WS
closes on ws.hello, and the operator sees an empty marketplace, an empty guild
board and no shard status, with the cause only in the server log. It cleared
only when an admin edited the number by hand in Admin → Shard.
Found while standing up a demo deployment for the marketing site's screenshots.
- `DEFAULT_PROTOCOL` → 4 (the constant used before an admin has saved anything)
- the `uo_link_config.protocol` column default → 4, at both declaration sites
- a protocol-4 one-shot mirroring the protocol-3 one, guarded by its own marker
so an operator who deliberately pins an older sidecar stays pinned, and
written `protocol < 4` so an install that never took the protocol-3 migration
is carried the whole way rather than one step
- three regression tests: the column default, the marker ordering, and the
`< 4` predicate
Co-Authored-By: Claude <noreply@anthropic.com>
Claude
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