multiplayer-next.md was a 1662-line mix of standing architecture spec
and task-completion tracking, most of which was dense per-task DONE
evidence for finished Phases 0-6. Split it:
- MULTIPLAYER_SPEC.md (new): the locked architecture decisions, wire
format, server-side input handling, prediction/reconciliation,
latency/frame-rate budget, and match lifecycle state machine -
standing design reference, not task-tracked.
- multiplayer-next.md (trimmed 1662 -> ~370 lines): only outstanding
work remains - §0 status, §7 Phase 7/8 task tables condensed to
"what's left" per task, §8-11 reference material (refactoring notes,
gotchas, testing, flagged items). Phases 0-6 collapsed to a pointer
at git history instead of ~500 lines of DONE evidence.
Also:
- Repointed every `multiplayer-next.md §N` code comment (N 1-6) across
Game/scripts, Game/tools and Game/tests to MULTIPLAYER_SPEC.md, since
those sections moved. Task-number references (`task N.N`, §7-11)
correctly still point at multiplayer-next.md.
- Updated CLAUDE.md's doc index and docs/TECH_STACK.md's spec-section
citations to match.
- TODO.md: added a "what's left to actually finish multiplayer
(human-actionable)" checklist pulled from multiplayer-next.md §0 and
docs/MATCHMAKING.md - things that need a person (hardware, a design
decision, a Steam App ID, hands on a controller), not more agent code.
Closes §8.43's 'failed-reconnect UX' gap, found immediately after
wiring connect_to_assignment() itself: even with that fix in place, a
connection failure had nowhere to go. connect_to_assignment()'s
synchronous failures (assignment missing/expired, invalid endpoint,
NetworkManager.join() erroring immediately) only ever emitted
assignment_connection_failed -- a signal nothing in the client
listened to. state.phase would stay stuck at ASSIGNED, the UI would
keep showing "Your match server is ready" forever, with no way back
to a fresh search.
Worse, the likelier real-world failure mode had no handler at all:
NetworkManager.join() returns OK immediately once the attempt starts,
but the actual ENet handshake can still fail asynchronously afterward
(unreachable server, refused connection, ENet's own ~5s connect
timeout). This is exactly the gap main_menu.gd's own
_on_connection_failed exists to cover for the direct-join flow (see
its header comment) -- nothing covered the equivalent for a
matchmaking-driven connect.
ControlPlaneClient now connects both assignment_connection_failed and
NetworkManager.connection_failed (guarded to state.phase == CONNECTING,
so it never misattributes an unrelated direct-join failure to a
matchmaking search) to state.fail(...), so either failure mode now
surfaces as a failed search the player can actually retry from.
Verified: three new test_control_plane_client.gd tests cover the
synchronous failure path, the async NetworkManager.connection_failed
path (via a real end-to-end ASSIGNED -> CONNECTING flow), and that an
unrelated connection_failed outside CONNECTING is correctly ignored.
220/220 tests pass, stable across 3 repeated runs, no crash, no
engine-level error; full make verify-multiplayer-local and the
complete make verify-enet-integration suite (all five cases) both
clean; zero new crash reports throughout.
Also fixes a markdown table-integrity mistake introduced while
documenting this in the same edit pass: an earlier Edit call
accidentally duplicated a sentence and dropped the row's closing
'remains' clause in §8.43 -- caught and corrected before commit via
the usual pipe-count check.
Closes §8.43's 'version-mismatch-specific client messaging' gap. Per
the user's explicit go-ahead to design new server behavior for this
(rather than only wiring up something that already existed, the
pattern every other fix this session followed): before this, there
was no server-side protocol rejection at all. queue_create accepted
any protocol_version >= 1 unconditionally, so an outdated client could
only ever discover a mismatch by waiting in the queue forever
unmatched -- the matcher's own compatibility check requires every
formed player to share an identical protocol_version -- with no error
and no explanation given to the player.
Server: Service.MinProtocolVersion (opt-in, zero by default so every
existing caller keeps accepting protocol_version 1 unconditionally)
rejects a below-floor queue_create with 426 Upgrade Required /
client_outdated before the request ever reaches the candidate
provider. Wired via cmd/control-plane's new --min-protocol-version
flag (validated non-negative at startup).
Client: ControlPlaneClient recognises HTTPClient.RESPONSE_UPGRADE_REQUIRED
on queue_create specifically and sets a distinct 'Your client is out
of date -- please update to continue searching' message instead of
the server's raw generic error string, and clears _last_queue_create
so can_retry_queue_create() never offers 'Retry Search' for a failure
that retrying with the same build can never fix.
Verified: go build/vet/test -race clean across every server package.
TestQueueCreateEnforcesMinProtocolVersion covers below-floor rejection
(candidate provider never reached), exactly-at-floor acceptance, and
the error body naming client_outdated; TestQueueCreateMinProtocolVersionZeroIsDisabled
proves the opt-in default doesn't change behavior for every existing
caller. Godot: test_outdated_client_receives_a_distinct_message_and_no_retry_offer
proves the distinct message and suppressed retry offer. Full Godot
suite (217/217, 0 failed, no crash), full make verify-multiplayer-local
gate, zero new crash reports.
A player who completed the entire queue -> proposal -> allocate ->
assign pipeline would reach ASSIGNED, see "Your match server is
ready", and then simply sit there forever. connect_to_assignment()
existed in control_plane_client.gd, fully validated (checks the
assignment is available and fresh, splits and validates the
endpoint, carries the join authorisation via MatchNet's hello payload
rather than the URL) with its own assignment_connection_started/
assignment_connection_failed signals, and multiplayer-next.md's own
§8.41 row already described it as wired -- but grepping the whole
client found zero callers. Nothing anywhere in matchmaking.gd or
control_plane_client.gd itself ever invoked it.
ControlPlaneClient._connect_when_assigned() now calls it automatically
the moment state.phase reaches ASSIGNED. Wired into the single call
site every queue-shaped HTTP response already shares (heartbeat,
recover, and resync-triggered recover alike, since the WebSocket
match-lifecycle path always funnels into a REST resync first), so
both the ordinary poll path and the WebSocket-push path are covered
without a second call site to keep in sync. Two orderings are handled:
if the assignment fetch triggered earlier by ASSIGNMENT_READY has
already completed, it connects immediately; if not, it defers via
_pending_connect_match_id and resolves once the assignment becomes
available. _connect_attempted_match_id guards against a duplicate or
replayed ASSIGNED event reattempting the connection.
Verified against the real Godot 4.7.1 binary now that headless
testing has resumed: two new test_control_plane_client.gd tests cover
both orderings and the duplicate-attempt guard directly (216/216
total, 0 failed, no crash, no engine-level error, stable across
repeated runs); full make verify-multiplayer-local and the complete
make verify-enet-integration suite (all five cases, including the
3-process match) both pass clean; zero new crash reports throughout.
multiplayer-next.md's §8.41 row is corrected to describe what was
actually true (connect_to_assignment existed but was never called)
rather than repeating the prior, inaccurate 'already wired' claim.
Closes most of §8.43's 'decline, regional outage retry UI, failed
reconnect, duplicate-action recovery beyond proposals' remaining
list -- turned out to be mostly stale doc, not missing code.
matchmaking.gd's decline button/handler already existed
(%DeclineButton, _on_decline_pressed, visibility toggled by
MatchmakingState.PROPOSED alongside accept). ControlPlaneClient's
can_retry_last_mutation()/retry_last_mutation() -- the generic
'duplicate-action recovery beyond proposals' and 'regional outage
retry' mechanism -- also already existed: any mutation (not just a
proposal response) becomes retryable on a transport failure or a
408/429/503 response, and matchmaking.gd's queue button already fell
back to it ('Retry Request'). Neither had any test coverage proving
the mechanism actually works for a non-proposal mutation --
is_retryable_mutation_response's pure classification was the only
thing tested.
Two new tests: test_generic_mutation_retry_recovers_after_a_transient_failure
proves can_retry_last_mutation() transitions from false (mutation
in flight) to true after a transport-level failure on an ordinary
queue_heartbeat, exactly the 'regional outage' case; test_generic_mutation_retry_is_not_offered_for_unsafe_failures
proves a 409 (revision conflict) is never offered as a blind retry
and that retry_last_mutation() fails closed with ERR_INVALID_DATA
rather than resending a stale mutation. retry_last_mutation's literal
network dispatch (HTTPRequest.request()) is not exercised -- it needs
a live SceneTree that test_runner.tscn's synchronous single-_ready()
execution model cannot provide mid-suite; the two tests cover the
can_retry_last_mutation() decision boundary and the fail-closed path
instead, which is what's actually new here.
Verified against the real Godot 4.7.1 binary now that headless
testing has resumed: test_runner.tscn 214/214 clean (no crash, no
engine-level error), full make verify-multiplayer-local re-run clean,
zero new crash reports.
Remaining in §8.43: version-mismatch-specific messaging (a protocol
rejection currently surfaces only as the server's generic error
string), failed-reconnect UX, and §8.16's arena selection/long-running
worker integration.
Josh Creek