Peer A failed to learn Peer B's games. The handshake only carried
library_rev/library_digest metadata, and the post-handshake sync path
compared those revisions against per-peer revision numbers that were
never advanced via this code path, so the games map for the remote
peer stayed empty and the UI never showed them.
The fix is to put the authoritative library data into the handshake
itself. Hello and HelloAck now carry a LibrarySnapshot directly, and
both perform_handshake_with_peer (outbound) and accept_inbound_hello
(inbound) apply that snapshot to the peer DB before emitting the UI
events. The initial peer-game-list event is now driven by the
handshake rather than by a follow-up LibrarySummary/LibrarySnapshot
roundtrip.
Bumps PROTOCOL_VERSION to 4 because the wire layout of Hello/HelloAck
changed. Per CLAUDE.md's protocol policy there is no compatibility
shim; older peers will fail the version check and be ignored.
Cleanups that fall out of the new design:
- The Hello / HelloAck library_rev and library_digest fields were
duplicated by the embedded LibrarySnapshot (which carries its own
library_rev, and whose digest is recomputed on apply). Collapsed
both messages to just `library: LibrarySnapshot` to remove the
foot-gun where the two could diverge.
- Request::LibrarySummary and Request::LibrarySnapshot are now dead
on the sender side and were removed along with their stream.rs
handlers and the LibrarySummary struct. LibraryDelta stays — it
is still sent from handlers.rs when the local library changes.
- record_remote_library previously called update_peer_library and
then apply_library_snapshot, which immediately overwrote the
rev/digest just written. Added update_peer_features and rewired
the call site so each peer-DB field is written exactly once.
update_peer_library is retained because discovery.rs still uses
it for the mDNS TXT-record path, where no snapshot is available.
- Removed the now-unused LibraryUpdate enum, select_library_update,
send_local_library_summary, send_local_library_update_if_needed,
LocalLibraryState::delta_since, build_library_summary,
send_library_summary, and send_library_snapshot.
Behavior change visible to users: when two peers come up on the LAN
they now see each other's full game lists immediately after the
handshake instead of waiting for a follow-up sync that, in the broken
case, never made the games visible at all.
Test Plan
- just clippy (clean for the touched crates)
- just test (workspace: all suites pass, including the two new
handshake tests: outbound_hello_carries_local_library_snapshot
and inbound_hello_applies_remote_library_snapshot, the latter
asserting PeerDiscovered + PeerCountUpdated + ListGames events
fire with the remote game visible)
- Manual: start `just peer-cli-alpha` and `just peer-cli-bravo` in
separate terminals; confirm each peer's game list shows the
other's library entries after discovery completes, without
requiring any additional command.
Refs
- FINDINGS.md: triage note that Claude's review surfaced only
in-scope cleanups (dead variants, duplicated header fields,
redundant DB writes, stale test fixture), all addressed here.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Follow-up hardening for 348a02c, where `listen_addr` was added to Hello and
HelloAck as `Option<SocketAddr>`. Code review surfaced three concrete problems
that the previous commit left open:
1. Cold-start asymmetry. Discovery and the QUIC/mDNS advertiser are spawned
concurrently. If discovery saw a cached peer advertisement before our own
advertiser had written `ctx.local_peer_addr`, our outbound Hello carried
`listen_addr: None`. The receiver's `peer_record_addr` then returned `None`
and silently dropped the Hello while we still recorded their HelloAck, so
peer A learned about peer B but B never learned about A until a later
handshake happened to win the race.
2. Duplicate game-list pipeline. The previous commit added
`refresh_peer_games`, which post-handshake issued a `ListGames` to fetch
`peer.games`. The library-sync path (`LibrarySnapshot`) already populates
the same field. Both could race on first contact and overwrite each other.
Worse, `refresh_peer_games` was misnamed: a `peer_game_count > 0` guard
turned it into a fetch-once-then-no-op helper, while
`handle_library_summary` independently re-triggered a full handshake when
`previous_count == 0` was observed, producing a redundant ping-pong on
every first contact.
3. Argument explosion. `perform_handshake_with_peer`, `spawn_library_resync`,
and `after_peer_library_recorded` had grown to 6-8 individual parameters
and acquired `#[allow(clippy::too_many_arguments)]` opt-outs. Every caller
was destructuring the same fields out of `Ctx`/`PeerCtx`.
Changes (all in one commit because they jointly enforce the same invariant:
"a peer is only ever recorded by its listener address, and the local
listener address must exist before we participate in the protocol"):
- `Hello.listen_addr` and `HelloAck.listen_addr` are now `SocketAddr`, not
`Option<SocketAddr>`. Wire-incompatible, but PROTOCOL_VERSION already moved
to 3 in 348a02c so no additional version bump is needed.
- `required_listen_addr` reads `ctx.local_peer_addr` and returns an
`eyre::Result`; `build_hello_from_state` and `build_hello_ack` both call
it, so an outbound or inbound Hello can no longer be constructed before
the local QUIC listener is bound. The inbound path maps this into a
`Response::InternalPeerError` so the remote peer fails cleanly instead of
seeing a malformed HelloAck.
- `run_peer_discovery` blocks on `wait_for_local_peer_addr` (25 ms poll,
shutdown-aware) before subscribing to the mDNS browser. This closes the
cold-start race for outbound handshakes at the source.
- `refresh_peer_games`, `request_game_list_from_peer`, and the
`previous_count == 0` re-handshake trigger are removed. The post-handshake
flow now relies solely on `LibrarySummary`/`LibrarySnapshot`/`LibraryDelta`
for peer-library state; `ListGames` survives only for the
`request_game_details_*` paths that fetch per-game file descriptions on
demand.
- New `HandshakeCtx` (with `from_ctx` and `from_peer_ctx` constructors)
replaces the long argument lists. All `too_many_arguments` allow-attrs in
`handshake.rs` are gone, and call sites in `handlers.rs`, `discovery.rs`,
and `stream.rs` collapse to a single clone.
- `handle_library_delta` no longer acquires a read lock on the apply path:
the `peer_addr` lookup moved into the `else` resync branch where it is
actually needed.
- `accept_inbound_hello`'s `remote_addr` parameter is renamed to
`transport_addr`. It is now used only for warn-log formatting, and the
new name signals that this is the ephemeral QUIC source port, never the
authoritative listener address that gets recorded.
User-visible effect: on cold start, peers can no longer end up with an
asymmetric view of each other ("A sees B but B never sees A"). First-contact
library sync now does one handshake plus one snapshot/delta exchange instead
of the previous handshake + ListGames + redundant follow-up handshake. The
direct-connect CLI path (`handle_connect_peer_command`) now fails fast with
"local peer listener address is not ready" if invoked before the QUIC server
has bound; this is intentional - the previous behaviour would have sent a
Hello that the receiver had to silently discard.
Test Plan:
- just fmt
- just clippy
- just test (80 peer + 3 cli + 5 tauri tests pass)
- just build
- Manual: bring up `just peer-cli-alpha`/`bravo`/`charlie`, confirm symmetric
peer discovery and that games show up on every side after one library
digest cycle, with no duplicated ListGames traffic in trace logs.
Refs: Review feedback on commit 348a02c (listener-address handshake fix).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Peers discovered over mDNS could still attribute later library sync traffic to
temporary QUIC source ports. In a real GUI LAN run this made Host B try to
push its library to Host A's outbound port instead of Host A's advertised
listener, so Host A discovered the peer but never saw its games.
Carry the stable listener address in Hello and HelloAck, and key library sync
messages by peer_id instead of inferring identity from the transport source
address. The handshake path now explicitly refreshes an empty peer library from
the known listener address, matching the reliability of the direct-connect CLI
path without overwriting richer snapshot state when it already arrived.
This changes the current wire protocol, so PROTOCOL_VERSION is bumped to 3 and
all peers must be rebuilt together. The architecture note now documents that
listener addresses come from mDNS or Hello/HelloAck, never from ephemeral QUIC
source ports.
Test Plan:
- just fmt
- just test
- just clippy
- just build
- git diff --check
Refs: Local Linux/Win11 GUI LAN test logs from 2026-05-18.
The follow-up backlog had drifted into three settled peer/runtime issues: the
legacy game-list fallback contradicted the one-wire-version policy, the Tauri
shell still re-derived local install state from disk after peer snapshots, and
`Availability::Downloading` existed even though active operations are already
reported through a separate operation table.
Remove the legacy `AnnounceGames` request and fallback service. Discovery now
ignores peers that do not advertise the current protocol and a peer id, and
library changes are sent through the current delta path only. This keeps the
runtime aligned with the documented current-build-only interoperability model.
Make peer `LocalGamesUpdated` snapshots authoritative for local fields in the
Tauri database. The GUI-side catalog still owns static metadata such as names,
sizes, and descriptions, but downloaded, installed, local version, and
availability now come from the peer runtime instead of a second whole-library
filesystem scan. Snapshot reconciliation also pins the missing-begin and
missing-finish lifecycle cases in tests.
Collapse availability back to the settled `Ready` and `LocalOnly` states.
Aggregation now counts only `Ready` peers as download sources, and the frontend
no longer carries a dead `Downloading` enum value.
The core peer also exposes the small non-GUI hooks needed by scripted callers:
startup options for state and mDNS, a local-ready event, direct connection, peer
snapshots, and an explicit post-download install policy. Those hooks reuse the
same current protocol path and do not add compatibility shims.
Test Plan:
- `git diff --check`
- `just fmt`
- `just clippy`
- `just test`
Refs: BACKLOG.md, FINDINGS.md, IMPL_DECISIONS.md
ddidderr
