Root cause: db_handle_init_resp marked sync_state=2 when my_dh==peer_dh
without checking that all my records fit in the confirmed prefix.
If mc > tp+1 (I have records beyond the common prefix), the tail was
never sent — lost records.
Fix:
- Remove special-case 'sc==0 && my_dh==peer_dh' (redundant, same bug)
- In general dh_match: if mc > tp+1, send remaining records [tp+1,mc-1]
using the same inline loop pattern as 'peer empty' branch
Test: 3 phases covering all dh_match paths:
- Phase 1: B empty+late instance → dh_match at tp=0 (sc=0) → tail-send 49
- Phase 2: A=80 B=50 → dh_match at tp=49 (sc>0, sparse) → tail-send 30
- Phase 3: fresh instances → peer empty → send all 30
- db_sync_on_conn_up: per-instance synced/skipped counters
- db_sync_peer_check_cb: summary INFO of check results
- db_sync_instance_add: peers_found + peers_synced counts
- db_handle_init_sync/initiate_sync: enhanced with tbl name
- db_handle_init_resp: tp + my_mc in sync complete/dh match
- db_handle_send_data: range + SYNC_DONE details; stop reason when mc>pk
- db_handle_sync_done: both counts + datahashes in mismatch; dh in confirm
- db_sync_recv_cb: INFO when instance NOT FOUND (timing race)
- cs_handle_channel_info_resp: sync readiness after channel ready
- cs_handle_welcome: note about db_sync peer_check timer
- on_db_sync_insert: counter (#1-3 then every 10) with ch/n/ts/dh/ct
- utun_instance.h: add chat_connections queue (indexed by node_id, 8 bytes)
- chat_sync.c: queue_new in init, queue_free in destroy, queue_find_data_by_index in cs_find_conn_for_node
- chat_sync.c: remove from queue in cs_on_conn_down
- chat_core.c: add to queue in connect_from_invite and connect_auto
- chat_core.c: remove from queue in cc_parallel_cleanup and ca_cleanup
- db_sync.c: replace linear conn search with queue_find_data_by_index (db_sync_send_hash)
- etcp_connections: keepalive SEND/RECV/DECRYPT_OK: DEBUG→TRACE; DECRYPT_FAIL: WARN→DEBUG
- db_sync_on_conn_up: skip sync if !conn->initialized, wait for next UP event
- db_sync peer_check_timer+instance_add: also check conn->initialized
- chat_sync cs_on_conn_up: ignore conn_up before initialized (cs_send fails otherwise)
- db_sync_on_conn_up log now includes init= and links=
- Replace get_time_us() with utun_gettimeofday() for PUSH message timestamps
(db_sync.c, chat_core.c) — monotonic clocks differ across Linux/Windows
- Fix merkle_sync: restart session timer in _handle_request to prevent
double-sided timeout when both nodes start member_sync simultaneously
- Fix INIT_RESP short-format: don't mark synced when my_count > peer_count
- Add db_sync_get_last_timestamp() to avoid duplicate timestamp generation
between db_sync and chat_core on_db_sync_insert
- Fix db_sync_stub to generate timestamps consistently
- build.sh: auto-rebuild chatgui via CMake after utun build
- Renamed TOPO_BGP to TOPO_GROUP with topo_group_id (64bit)
- Added TOPO_GROUPS container (ll_queue group_list) in UTUN_INSTANCE
- Memory pools moved from TOPO_GROUP to TOPO_GROUPS (instance-level)
- Default group: TOPO_GROUP_UTUN = 0x8000000000000000
- topo_groups_get_default() searches by group_id, not just first entry
- All topo_bgp_* renamed to topo_group_*; function signatures updated
- Files: topo_bgp.h/c -> topo_group.h/c
Evgeny