Inviting an official robot (e.g. 2854207029) into a group made QQ push the
group_member_increase notice twice, so SnowLuma emitted two
notice.group_increase events; a normal member produced one.
Root cause (RE of wrapper.linux.node): QQ NT dedups every received system
message in sys_msg_mgr.cc::ProcessRecvSysMsg (sub_37BADE0) by a global_key
`{peerUid}_{chatType}_{msg_seq}_{random}` (sub_37BC4E0) — an already-seen key
is dropped ("ignore dup msg") before any listener sees it. The per-message
discriminators msg_seq (attr 40003 = contentHead field 5) and random (attr
40002 = contentHead field 4) are exactly head.sequence and head.msgId
(msg_header_codec_helper.cc sub_37C8AD0). Kernel-based bots (NapCat/LLOneBot)
receive events after this dedup; SnowLuma reads the raw OlPush before it.
Mirror it: SysMsgDedup, a per-account bounded ring that drops a duplicate
system push by (msgType, subType, fromUin, sequence, msgId). Push-level (drops
the whole duplicate like NT), live path only (Bridge owns the tracker; the
forward re-parse passes none), system kinds only (chat messages excluded), and
never dedups a push lacking a server identity (sequence or msgId 0).
DrSmoothl
1bdb8a40c4