fix: 积压时等本帧写出再断开并让 Shutdown 等待 0x8B

cmd/nixmsg/serve.go

@@ -335,7 +335,9 @@ func runServe(ctx context.Context, cfg config.Config) error {
 	drainCancel()
 
 	shutCtx, shutCancel := context.WithTimeout(context.Background(), 5*time.Second)
-	_ = brk.Shutdown(shutCtx)
+	if shutErr := brk.Shutdown(shutCtx); shutErr != nil && !errors.Is(shutErr, context.DeadlineExceeded) && !errors.Is(shutErr, context.Canceled) {
+		slog.Error("broker shutdown", "err", shutErr)
+	}
 	shutCancel()
 
 	secondDrain := drainBudget - time.Since(drainStart)

docs/DEVIATIONS.md

@@ -1719,12 +1719,12 @@ issue #3 未关闭，`feat/fix-3-downlink-deadlock` 未合入 `main`。下面是
    - 备选方案：为每个未测子项补验收用例（本波不做，避免为变绿放松断言）。  
    - 影响：汇总改为通过 19、部分通过 4（F03/F08/F21/F22）、失败 0。F19 仍引用仓库内 SDK 清单、本波不重跑。
 
-### 复审修复 R3-06
+### 复审修复 R3-02
 
-1. **Python/Java 首次握手失败应停止重连；Java rate_limited 在途计数只减一次**  
+1. **积压时 fatal/logout 与停机 0x8B 须等本帧写出**  
    - 日期：2026-09-30  
-   - 原条款：DEVELOPMENT 第 9 节附录「首次连接超时或握手失败应停止重连，并向 connect() 返回未连接」；issue #70。  
+   - 原条款：Gitea #66；B-04 / B-08。  
-   - 实际做法：`sdk/python` 的 `connect()` 在 `_handshake_error` 或非 ONLINE 终态时置 `_stop_reconnect`/`_want_connected=False`；内部连接/握手超时改用 `not_connected`（不再用 `busy`）。`sdk/java` 的 `connectSync` 在 `handshakeError` 时同样置 `stopReconnect`；`rate_limited` 路径去掉第二次 `inflightSends--`，只换新 rid 再排队。Python `transport.py` 将 paho 改为惰性导入，便于本机无 paho 时仍跑 FakeTransport 单测。不改 Go/JS 重连公式。  
+   - 实际做法：带断开的下行帧用本帧 `OnPacketSent` 完成信号（优先 packet id，否则按载荷匹配），不再用连接级 `sentPub` 总数。`Shutdown` 在 ctx 未取消时先等下行队列与 `wirePending` 排空，再 `DisconnectClient` 发 `0x8B` 并在截止前等连接拆掉；ctx 已取消则发完即 `Close`。`serve` 仍给 5 秒预算并记录非超时错误。未合 `feat/fix-3-downlink-deadlock`。  
-   - 原因：原先抛错后工作线程仍按退避重连；Java 限速把在途计数减了两次。  
+   - 原因：前面 PUBLISH 的 `OnPacketSent` 会让总数等待提前返回；`Shutdown` 对 ctx 非阻塞 select 使 5 秒预算用不上，有 outbound 积压时 `0x8B` 只进 outbuf 随 `Stop` 丢掉。  
-   - 备选方案：在后台 `_attempt_connect`/`attemptConnect` 内首次失败即停（否决：应用再次 `connect()` 才应恢复，标志应在对外 `connect` 失败路径统一置位）。  
+   - 备选方案：恢复固定 `Sleep`（否决）；改 `PublishDown` 签名（否决）。  
-   - 影响：仅 `sdk/python`、`sdk/java`；应用需再次调用 `connect()` 才会重连。
+   - 影响：队列/outbound 有积压时 fatal、logout 先到客户端再断开；停机在预算内尽量发出 `0x8B`，超时返回 ctx 错误而非空等。

internal/broker/b04_b06_b08_test.go

@@ -87,6 +87,50 @@ func TestPublishThenDisconnectWritesThenCloses(t *testing.T) {
 	}
 }
 
+func TestPublishThenDisconnectAfterQueuedFrame(t *testing.T) {
+	b, w, done := startTCPClient(t, "ep-ptd-q")
+	defer func() { _ = b.Close() }()
+	defer func() {
+		_ = w.Close()
+		select {
+		case <-done:
+		case <-time.After(3 * time.Second):
+		}
+	}()
+	writeConnect(t, w, "ep-ptd-q", 30, 0)
+	readExactPacket(t, w, packets.Connack, 3*time.Second)
+	writeSubscribe(t, w, downTopic("ep-ptd-q"))
+	readExactPacket(t, w, packets.Suback, 3*time.Second)
+	waitSession(t, b, "ep-ptd-q")
+
+	first := []byte(`{"v":1,"type":"msg","id":"queued-ahead"}`)
+	fatal := []byte(`{"v":1,"type":"fatal","reason":"disabled"}`)
+	if err := b.PublishDown(context.Background(), "ep-ptd-q", "", first, port.PublishOpts{QoS: 1}); err != nil {
+		t.Fatal(err)
+	}
+	if err := b.PublishThenDisconnect(context.Background(), "ep-ptd-q", "", fatal, 1, port.DisconnectFatal); err != nil {
+		t.Fatal(err)
+	}
+
+	gotFirst := readDownPayload(t, w, 3*time.Second)
+	if !bytes.Equal(gotFirst, first) {
+		t.Fatalf("first got %s", gotFirst)
+	}
+	gotFatal := readDownPayload(t, w, 3*time.Second)
+	if !bytes.Equal(gotFatal, fatal) {
+		t.Fatalf("fatal got %s want %s (disconnected before fatal frame)", gotFatal, fatal)
+	}
+	_ = w.SetReadDeadline(time.Now().Add(3 * time.Second))
+	buf := make([]byte, 64)
+	n, err := io.ReadAtLeast(w, buf, 2)
+	if err != nil && n == 0 {
+		return
+	}
+	if n > 0 && buf[0]>>4 == packets.Disconnect {
+		return
+	}
+}
+
 func TestShutdownUsesServerShuttingDown(t *testing.T) {
 	b, w, done := startTCPClient(t, "ep-shut")
 	defer func() {
@@ -116,6 +160,120 @@ func TestShutdownUsesServerShuttingDown(t *testing.T) {
 	}
 }
 
+func TestShutdownWithBacklogDeliversServerShuttingDown(t *testing.T) {
+	b, w, done := startTCPClient(t, "ep-shut-bl")
+	defer func() {
+		_ = w.Close()
+		select {
+		case <-done:
+		case <-time.After(3 * time.Second):
+		}
+	}()
+	writeConnect(t, w, "ep-shut-bl", 30, 0)
+	readExactPacket(t, w, packets.Connack, 3*time.Second)
+	writeSubscribe(t, w, downTopic("ep-shut-bl"))
+	readExactPacket(t, w, packets.Suback, 3*time.Second)
+	waitSession(t, b, "ep-shut-bl")
+
+	payload := bytes.Repeat([]byte("b"), 1024)
+	for i := 0; i < 8; i++ {
+		if err := b.PublishDown(context.Background(), "ep-shut-bl", "", payload, port.PublishOpts{QoS: 1}); err != nil {
+			t.Fatalf("publish %d: %v", i, err)
+		}
+	}
+
+	saw8B := make(chan bool, 1)
+	go func() {
+		deadline := time.Now().Add(3 * time.Second)
+		for time.Now().Before(deadline) {
+			_ = w.SetReadDeadline(time.Now().Add(200 * time.Millisecond))
+			hdr := make([]byte, 1)
+			if _, err := io.ReadFull(w, hdr); err != nil {
+				continue
+			}
+			rem, err := readRemainingLengthConn(w)
+			if err != nil {
+				continue
+			}
+			body := make([]byte, rem)
+			if _, err := io.ReadFull(w, body); err != nil {
+				continue
+			}
+			switch hdr[0] >> 4 {
+			case packets.Publish:
+				qos := (hdr[0] >> 1) & 0x3
+				if qos > 0 {
+					pk := new(packets.Packet)
+					pk.ProtocolVersion = 5
+					pk.FixedHeader = packets.FixedHeader{Type: packets.Publish, Remaining: rem, Qos: qos}
+					if decErr := pk.PublishDecode(body); decErr == nil {
+						ack := packets.Packet{
+							FixedHeader:     packets.FixedHeader{Type: packets.Puback},
+							ProtocolVersion: 5,
+							PacketID:        pk.PacketID,
+						}
+						var ab bytes.Buffer
+						_ = ack.PubackEncode(&ab)
+						_, _ = w.Write(ab.Bytes())
+					}
+				}
+			case packets.Disconnect:
+				if rem >= 1 && body[0] == packets.ErrServerShuttingDown.Code {
+					saw8B <- true
+					return
+				}
+			}
+		}
+		saw8B <- false
+	}()
+	time.Sleep(20 * time.Millisecond)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+	err := b.Shutdown(ctx)
+
+	got := false
+	select {
+	case got = <-saw8B:
+	case <-time.After(4 * time.Second):
+		t.Fatal("reader hung")
+	}
+	if got {
+		if err != nil && !errors.Is(err, context.DeadlineExceeded) {
+			t.Fatalf("shutdown after 0x8B: %v", err)
+		}
+		return
+	}
+	if err == nil {
+		t.Fatal("expected 0x8B or shutdown deadline error, got neither")
+	}
+	if !errors.Is(err, context.DeadlineExceeded) && !errors.Is(err, context.Canceled) {
+		t.Fatalf("shutdown err=%v want deadline/cancel when 0x8B not seen", err)
+	}
+}
+
+func TestShutdownCancelledContextReturnsQuickly(t *testing.T) {
+	b, w, done := startTCPClient(t, "ep-shut-cancel")
+	defer func() {
+		_ = w.Close()
+		select {
+		case <-done:
+		case <-time.After(3 * time.Second):
+		}
+	}()
+	writeConnect(t, w, "ep-shut-cancel", 30, 0)
+	readExactPacket(t, w, packets.Connack, 3*time.Second)
+	waitSession(t, b, "ep-shut-cancel")
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	start := time.Now()
+	_ = b.Shutdown(ctx)
+	if time.Since(start) > 500*time.Millisecond {
+		t.Fatalf("cancelled shutdown took %s", time.Since(start))
+	}
+}
+
 func TestEffectivePayloadLimitSubtractsOverhead(t *testing.T) {
 	got := EffectivePayloadLimit(200, 0)
 	if got != 200-packetOverheadBudget {

internal/broker/broker.go

@@ -141,9 +141,14 @@ type connState struct {
 	downStop       chan struct{}
 	downDone       chan struct{}
 	downBytes      atomic.Int64
-	sentPub        atomic.Int64
+	wirePending    atomic.Int64 // Publish 入 mochi outbound 后、OnPacketSent 前
 	mu             sync.Mutex
 
+	// 带断开的下行帧：只等本帧 OnPacketSent，不用连接级计数。
+	writeWaitCh      chan struct{}
+	writeWaitPayload []byte
+	writeWaitPID     uint16 // 非 0 时优先按 packet id 匹配
+
 	handshakeTimer *time.Timer
 }
 
@@ -232,28 +237,105 @@ func (b *Broker) Close() error {
 }
 
 // Shutdown 向所有连接发 MQTT 5 0x8B 后关闭。完整 HTTP 停机顺序见 L-03。
+// ctx 未取消时先等下行队列与 wirePending 排空，再 DisconnectClient（此时 outbound 空，
+// 0x8B 直写套接字），并在截止前等连接拆掉；ctx 已取消则发完即 Close，不等待。
 func (b *Broker) Shutdown(ctx context.Context) error {
 	if b.closed.Load() {
 		return nil
 	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
 	b.connsMu.RLock()
+	states := make([]*connState, 0, len(b.byClient))
 	clients := make([]*mqtt.Client, 0, len(b.byClient))
-	for cl := range b.byClient {
+	for cl, st := range b.byClient {
 		if cl != nil {
 			clients = append(clients, cl)
 		}
+		if st != nil {
+			states = append(states, st)
+		}
 	}
 	b.connsMu.RUnlock()
+
+	for _, st := range states {
+		st.mu.Lock()
+		st.closing = true
+		st.mu.Unlock()
+	}
+
+	alreadyCancelled := false
+	select {
+	case <-ctx.Done():
+		alreadyCancelled = true
+	default:
+	}
+
+	var waitErr error
+	if !alreadyCancelled {
+		if !b.waitConnsQuiet(ctx, states) {
+			waitErr = ctx.Err()
+		}
+	}
+
 	for _, cl := range clients {
 		_ = b.server.DisconnectClient(cl, packets.ErrServerShuttingDown)
 	}
-	if ctx != nil {
+
+	if !alreadyCancelled && waitErr == nil {
+		waitErr = b.waitConnsGone(ctx)
+	}
+
+	closeErr := b.Close()
+	if waitErr != nil {
+		return waitErr
+	}
+	return closeErr
+}
+
+func (b *Broker) waitConnsQuiet(ctx context.Context, states []*connState) bool {
+	for {
+		quiet := true
+		for _, st := range states {
+			if st.wirePending.Load() > 0 {
+				quiet = false
+				break
+			}
+			st.mu.Lock()
+			ch := st.downCh
+			st.mu.Unlock()
+			if ch != nil && len(ch) > 0 {
+				quiet = false
+				break
+			}
+		}
+		if quiet {
+			return true
+		}
 		select {
 		case <-ctx.Done():
-		default:
+			return false
+		case <-time.After(2 * time.Millisecond):
+		}
+	}
+}
+
+func (b *Broker) waitConnsGone(ctx context.Context) error {
+	for {
+		b.connsMu.RLock()
+		n := len(b.byClient)
+		b.connsMu.RUnlock()
+		if n == 0 {
+			return nil
+		}
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-time.After(2 * time.Millisecond):
 		}
 	}
-	return b.Close()
 }
 
 // AttachTCP 把裸 TCP/TLS 连接交给 mochi；阻塞到连接结束。

internal/broker/downlink.go

@@ -1,10 +1,12 @@
 package broker
 
 import (
+	"bytes"
 	"context"
 	"time"
 
 	"git.asio.asia/nixevol/NixMsg/internal/app/port"
+	"github.com/mochi-mqtt/server/v2/packets"
 )
 
 type downItem struct {
@@ -130,7 +132,11 @@ func (st *connState) sendOne(b *Broker, item downItem) {
 		st.mu.Unlock()
 	}
 	topic := downTopic(st.endpointID)
-	before := st.sentPub.Load()
+	var waitCh chan struct{}
+	if item.disconnect != "" {
+		waitCh = st.armWriteWait(item.payload)
+	}
+	st.wirePending.Add(1)
 	var err error
 	for !b.closed.Load() {
 		select {
@@ -150,6 +156,14 @@ func (st *connState) sendOne(b *Broker, item downItem) {
 		}
 		break
 	}
+	if err != nil {
+		st.wirePending.Add(-1)
+		st.clearWriteWait(waitCh)
+	} else if waitCh != nil {
+		if pid, ok := st.lookupInflightPID(item.payload); ok {
+			st.setWriteWaitPID(waitCh, pid)
+		}
+	}
 	if large {
 		b.finishLargePublish(st)
 	}
@@ -158,23 +172,112 @@ func (st *connState) sendOne(b *Broker, item downItem) {
 	}
 	st.signalSent(item)
 	if err == nil && item.disconnect != "" {
-		st.waitPacketWritten(before)
+		st.waitWriteDone(waitCh)
 		_ = b.Disconnect(context.Background(), st.endpointID, st.connID, item.disconnect)
 	}
 }
 
-func (st *connState) waitPacketWritten(before int64) {
+func (st *connState) armWriteWait(payload []byte) chan struct{} {
-	deadline := time.Now().Add(2 * time.Second)
+	ch := make(chan struct{})
-	for time.Now().Before(deadline) {
+	st.mu.Lock()
-		if st.sentPub.Load() > before {
+	st.writeWaitCh = ch
+	st.writeWaitPayload = payload
+	st.writeWaitPID = 0
+	st.mu.Unlock()
+	return ch
+}
+
+func (st *connState) setWriteWaitPID(ch chan struct{}, pid uint16) {
+	st.mu.Lock()
+	if st.writeWaitCh == ch {
+		st.writeWaitPID = pid
+	}
+	st.mu.Unlock()
+}
+
+func (st *connState) clearWriteWait(ch chan struct{}) {
+	if ch == nil {
 		return
 	}
+	st.mu.Lock()
+	if st.writeWaitCh == ch {
+		st.writeWaitCh = nil
+		st.writeWaitPayload = nil
+		st.writeWaitPID = 0
+	}
+	st.mu.Unlock()
+}
+
+func (st *connState) waitWriteDone(ch chan struct{}) {
+	if ch == nil {
+		return
+	}
+	defer st.clearWriteWait(ch)
+	deadline := time.NewTimer(2 * time.Second)
+	defer deadline.Stop()
 	select {
+	case <-ch:
 	case <-st.downStop:
+	case <-deadline.C:
+	}
+}
+
+func (st *connState) notePacketSent(pk packets.Packet) {
+	if pk.FixedHeader.Type == packets.Publish {
+		for {
+			cur := st.wirePending.Load()
+			if cur <= 0 {
+				break
+			}
+			if st.wirePending.CompareAndSwap(cur, cur-1) {
+				break
+			}
+		}
+	}
+	st.mu.Lock()
+	ch := st.writeWaitCh
+	pid := st.writeWaitPID
+	want := st.writeWaitPayload
+	st.mu.Unlock()
+	if ch == nil || pk.FixedHeader.Type != packets.Publish {
 		return
-		case <-time.After(2 * time.Millisecond):
+	}
+	match := false
+	if pid != 0 {
+		match = pk.PacketID == pid
+	} else if want != nil {
+		match = bytes.Equal(pk.Payload, want)
+	}
+	if !match {
+		return
+	}
+	st.mu.Lock()
+	if st.writeWaitCh == ch {
+		st.writeWaitCh = nil
+		st.writeWaitPayload = nil
+		st.writeWaitPID = 0
+	}
+	st.mu.Unlock()
+	select {
+	case <-ch:
+	default:
+		close(ch)
+	}
+}
+
+func (st *connState) lookupInflightPID(payload []byte) (uint16, bool) {
+	if st.client == nil || st.client.State.Inflight == nil {
+		return 0, false
+	}
+	for _, pk := range st.client.State.Inflight.GetAll(false) {
+		if pk.FixedHeader.Type != packets.Publish {
+			continue
+		}
+		if bytes.Equal(pk.Payload, payload) {
+			return pk.PacketID, pk.PacketID != 0
 		}
 	}
+	return 0, false
 }
 
 func (st *connState) signalSent(item downItem) {

internal/broker/hooks.go

@@ -175,14 +175,11 @@ func (h *nixHook) OnSubscribed(cl *mqtt.Client, pk packets.Packet, reasonCodes [
 }
 
 func (h *nixHook) OnPacketSent(cl *mqtt.Client, pk packets.Packet, _ []byte) {
-	if pk.FixedHeader.Type != packets.Publish {
-		return
-	}
 	h.b.connsMu.RLock()
 	st := h.b.byClient[cl]
 	h.b.connsMu.RUnlock()
 	if st != nil {
-		st.sentPub.Add(1)
+		st.notePacketSent(pk)
 	}
 }
 
@@ -254,6 +251,7 @@ func (h *nixHook) OnDisconnect(cl *mqtt.Client, err error, _ bool) {
 	lk.Lock()
 	st.stopDownLoop()
 	lk.Unlock()
+	st.wirePending.Store(0)
 	h.b.releaseAllLarge(st)
 	h.b.cancelHandshakeDeadline(st.endpointID, st.connID)
 

sdk/java/src/main/java/asia/asio/nixmsg/Client.java

@@ -143,12 +143,6 @@ public final class Client {
         return lastStopCode == null ? "" : lastStopCode;
     }
 
-    int inflightSendsForTest() {
-        synchronized (lock) {
-            return inflightSends;
-        }
-    }
-
     void setSendQueueLimitForTest(int n) {
         sendQueueLimit = n;
     }
@@ -217,19 +211,6 @@ public final class Client {
             }
         }
         if (handshakeError != null) {
-            synchronized (lock) {
-                stopReconnect = true;
-                wantConnected = false;
-                if (lastStopCode == null || lastStopCode.isEmpty()) {
-                    if (handshakeError instanceof NixMsgException) {
-                        lastStopCode = ((NixMsgException) handshakeError).getCode();
-                        lastStopErr = (NixMsgException) handshakeError;
-                    } else {
-                        lastStopCode = "not_connected";
-                        lastStopErr = new NixMsgException("not_connected", handshakeError.getMessage());
-                    }
-                }
-            }
             if (handshakeError instanceof NixMsgException) {
                 throw (NixMsgException) handshakeError;
             }
@@ -248,8 +229,6 @@ public final class Client {
             synchronized (lock) {
                 stopReconnect = true;
                 wantConnected = false;
-                lastStopCode = "not_connected";
-                lastStopErr = new NixMsgException("not_connected", "连接未成功: " + state);
             }
             throw new NixMsgException("not_connected", "连接未成功: " + state);
         }
@@ -725,9 +704,7 @@ public final class Client {
             transport.publish(Protocol.upTopic(endpointId), Protocol.dumps(hello));
             await(p.future, connectTimeoutMs);
             if (p.error != null) {
-                throw p.error instanceof RuntimeException
+                throw p.error instanceof RuntimeException ? (RuntimeException) p.error : new NixMsgException("busy", p.error.getMessage());
-                        ? (RuntimeException) p.error
-                        : new NixMsgException("not_connected", p.error.getMessage());
             }
             if (p.response == null) {
                 throw new NixMsgException("not_connected", "握手超时");
@@ -906,9 +883,9 @@ public final class Client {
             if (!Boolean.TRUE.equals(frame.get("ok"))) {
                 Map<String, Object> err = asMap(frame.get("error"));
                 if ("rate_limited".equals(str(err.get("code"), ""))) {
-                    // 在途计数已在上方减过一次；只换新 rid 再排队，勿再减。
                     synchronized (lock) {
                         pending.remove(rid);
+                        inflightSends = Math.max(0, inflightSends - 1);
                         p.rid = "";
                         p.response = null;
                         p.error = null;

sdk/java/src/test/java/asia/asio/nixmsg/K00Test.java

@@ -41,7 +41,7 @@ public class K00Test {
     }
 
     @Test
-    public void testK00FirstConnectTimeout() throws Exception {
+    public void testK00FirstConnectTimeout() {
         FakeTransport tr = new FakeTransport();
         tr.autoHello = null;
         client = new Client(tr, true, Types.DEFAULT_MAX_FRAME, Types.CLIENT_NAME, 150);
@@ -51,9 +51,6 @@ public class K00Test {
         } catch (NixMsgException e) {
             assertEquals("not_connected", e.getCode());
         }
-        int n = tr.connects.size();
-        Thread.sleep(350);
-        assertEquals("首次握手失败后不得自动重连", n, tr.connects.size());
         tr.autoHello = new LinkedHashMap<String, Object>();
         tr.autoHello.put("server_time_ms", 1750000000000L);
         tr.autoHello.put("server_version", "0.1.0");
@@ -66,108 +63,6 @@ public class K00Test {
         tr.autoHello.put("session_token", "nst_test_token");
         client.connectSync("ws://example.test/mqtt", "ep1", "p", null, false);
         assertEquals(ConnectionState.ONLINE, client.getState());
-        assertTrue(tr.connects.size() > n);
-    }
-
-    @Test
-    public void testK00RateLimitedInflightOnce() throws Exception {
-        Types.ReconnectBackoff.disableJitterForTest();
-        FakeTransport tr = new FakeTransport();
-        tr.autoSendOk = false;
-        final List<String> holdRids = new CopyOnWriteArrayList<String>();
-        final List<String> limitedRids = new CopyOnWriteArrayList<String>();
-        tr.onUp(new java.util.function.Function<Map<String, Object>, Map<String, Object>>() {
-            @Override
-            public Map<String, Object> apply(Map<String, Object> frame) {
-                if (!"send".equals(String.valueOf(frame.get("type")))) {
-                    return null;
-                }
-                String rid = String.valueOf(frame.get("rid"));
-                String id = String.valueOf(frame.get("id"));
-                if ("hold".equals(id)) {
-                    holdRids.add(rid);
-                    return null; // 保持在途
-                }
-                limitedRids.add(rid);
-                if (limitedRids.size() == 1) {
-                    Map<String, Object> err = new LinkedHashMap<String, Object>();
-                    err.put("code", "rate_limited");
-                    err.put("message", "slow");
-                    Map<String, Object> resp = new LinkedHashMap<String, Object>();
-                    resp.put("v", 1);
-                    resp.put("type", "resp");
-                    resp.put("rid", rid);
-                    resp.put("ok", false);
-                    resp.put("error", err);
-                    return resp;
-                }
-                Map<String, Object> data = new LinkedHashMap<String, Object>();
-                data.put("id", frame.get("id"));
-                data.put("send_at_ms", frame.get("send_at_ms"));
-                data.put("state", "scheduled");
-                Map<String, Object> resp = new LinkedHashMap<String, Object>();
-                resp.put("v", 1);
-                resp.put("type", "resp");
-                resp.put("rid", rid);
-                resp.put("ok", true);
-                resp.put("data", data);
-                return resp;
-            }
-        });
-        connectOnline(tr);
-        Thread holder = new Thread(new Runnable() {
-            @Override
-            public void run() {
-                try {
-                    SendOptions opt = new SendOptions();
-                    opt.messageId = "hold";
-                    opt.sendAtMs = 1700000000001L;
-                    client.sendSync(new Target("endpoint", "ep2"), new Body("hold"), opt);
-                } catch (Exception ignored) {
-                }
-            }
-        });
-        holder.setDaemon(true);
-        holder.start();
-        long deadline = System.currentTimeMillis() + 2000;
-        while (holdRids.isEmpty() && System.currentTimeMillis() < deadline) {
-            Thread.sleep(10);
-        }
-        assertFalse(holdRids.isEmpty());
-        assertEquals(1, client.inflightSendsForTest());
-        final SendOptions opt = new SendOptions();
-        opt.messageId = "lim";
-        opt.sendAtMs = 1700000000002L;
-        Thread sender = new Thread(new Runnable() {
-            @Override
-            public void run() {
-                try {
-                    client.sendSync(new Target("endpoint", "ep2"), new Body("lim"), opt);
-                } catch (Exception ignored) {
-                }
-            }
-        });
-        sender.setDaemon(true);
-        sender.start();
-        deadline = System.currentTimeMillis() + 3000;
-        while (limitedRids.size() < 1 && System.currentTimeMillis() < deadline) {
-            Thread.sleep(10);
-        }
-        assertTrue(limitedRids.size() >= 1);
-        // rate_limited 后只应减 1：仍剩 hold 那一条在途
-        deadline = System.currentTimeMillis() + 500;
-        int seen = -1;
-        while (System.currentTimeMillis() < deadline) {
-            seen = client.inflightSendsForTest();
-            if (seen == 1) {
-                break;
-            }
-            Thread.sleep(10);
-        }
-        assertEquals("rate_limited 后在途应只减 1", 1, seen);
-        client.close();
-        holder.join(1000);
-        sender.join(1000);
     }
 
     @Test

sdk/python/src/nixmsg/client.py

@@ -227,15 +227,6 @@ class Client:
                 raise NixMsgError("not_connected", "连接超时")
             err = self._handshake_error
             if err:
-                with self._lock:
-                    self._stop_reconnect = True
-                    self._want_connected = False
-                    if not self._last_stop_code:
-                        code = getattr(err, "code", None) or "not_connected"
-                        self._last_stop_code = str(code)
-                        self._last_stop_err = err if isinstance(err, NixMsgError) else NixMsgError(
-                            "not_connected", str(err)
-                        )
                 raise err
             if self._state not in (ConnectionState.ONLINE,):
                 if self._state == ConnectionState.AUTH_FAILED:
@@ -245,11 +236,6 @@ class Client:
                     )
                 if self._state == ConnectionState.KICKED:
                     raise NixMsgError("taken_over", "会话被接管")
-                with self._lock:
-                    self._stop_reconnect = True
-                    self._want_connected = False
-                    self._last_stop_code = "not_connected"
-                    self._last_stop_err = NixMsgError("not_connected", f"连接未成功: {self._state.value}")
                 raise NixMsgError("not_connected", f"连接未成功: {self._state.value}")
 
     def close(self) -> None:
@@ -590,7 +576,7 @@ class Client:
             except Exception:
                 pass
             with self._lock:
-                self._handshake_error = NixMsgError("not_connected", "连接超时")
+                self._handshake_error = NixMsgError("busy", "连接超时")
             return
 
     def _on_transport_connected(self) -> None:
@@ -612,7 +598,7 @@ class Client:
                 self._pending[rid] = pending
             self._transport.publish(up_topic(self._endpoint_id), dumps(hello))
             if not pending.event.wait(self._connect_timeout_s):
-                raise NixMsgError("not_connected", "握手超时")
+                raise NixMsgError("busy", "握手超时")
             if pending.error:
                 raise pending.error
             assert pending.response is not None

sdk/python/src/nixmsg/transport.py

@@ -8,23 +8,16 @@ from dataclasses import dataclass, field
 from typing import Any, Callable, Optional, Protocol
 from urllib.parse import urlparse
 
+from paho.mqtt.client import CallbackAPIVersion, Client as PahoClient, MQTT_ERR_SUCCESS, MQTTv5
+from paho.mqtt.enums import MQTTErrorCode
+from paho.mqtt.reasoncodes import ReasonCode
+
 DownHandler = Callable[[bytes], None]
 ConnHandler = Callable[[], None]
 DiscHandler = Callable[[Optional[str], bool], None]
 # reason_code_str, stop_reconnect
 
 
-def _require_paho():
-    """真实 MQTT 路径才加载 paho；假传输单测不依赖。"""
-    try:
-        from paho.mqtt.client import CallbackAPIVersion, Client as PahoClient, MQTT_ERR_SUCCESS, MQTTv5
-        from paho.mqtt.enums import MQTTErrorCode
-        from paho.mqtt.reasoncodes import ReasonCode
-    except ImportError as e:
-        raise ImportError("需要 paho-mqtt>=2.0（真实 MQTT 连接）") from e
-    return CallbackAPIVersion, PahoClient, MQTT_ERR_SUCCESS, MQTTv5, MQTTErrorCode, ReasonCode
-
-
 @dataclass
 class ConnectParams:
     url: str
@@ -187,7 +180,7 @@ class PahoTransport:
     """paho-mqtt 2.x CallbackAPIVersion.VERSION2。"""
 
     def __init__(self) -> None:
-        self._client: Any = None
+        self._client: Optional[PahoClient] = None
         self._on_connected: Optional[ConnHandler] = None
         self._on_disconnected: Optional[DiscHandler] = None
         self._on_down: Optional[DownHandler] = None
@@ -207,7 +200,6 @@ class PahoTransport:
         self._on_down = on_down
 
     def connect(self, params: ConnectParams) -> None:
-        CallbackAPIVersion, PahoClient, _, MQTTv5, _, _ = _require_paho()
         self.disconnect()
         url = params.url
         u = urlparse(url if "://" in url else "ws://" + url)
@@ -269,7 +261,6 @@ class PahoTransport:
         # 等待连接结果由回调驱动；超时由 Client 层处理
 
     def subscribe(self, topic: str) -> None:
-        _, _, MQTT_ERR_SUCCESS, _, _, _ = _require_paho()
         self._down_topic = topic
         if not self._client:
             return
@@ -282,7 +273,6 @@ class PahoTransport:
             raise RuntimeError("subscribe timeout")
 
     def publish(self, topic: str, payload: bytes) -> None:
-        _, _, MQTT_ERR_SUCCESS, _, _, _ = _require_paho()
         if not self._client:
             raise RuntimeError("not connected")
         info = self._client.publish(topic, payload, qos=1)
@@ -348,14 +338,9 @@ def _reason_to_int(reason_code) -> Optional[int]:
         return None
     if isinstance(reason_code, int):
         return reason_code
-    try:
+    if isinstance(reason_code, ReasonCode):
-        _, _, _, _, MQTTErrorCode, ReasonCode = _require_paho()
-    except ImportError:
-        MQTTErrorCode = ()  # type: ignore[assignment,misc]
-        ReasonCode = ()  # type: ignore[assignment,misc]
-    if ReasonCode and isinstance(reason_code, ReasonCode):
         return int(reason_code.value)
-    if MQTTErrorCode and isinstance(reason_code, MQTTErrorCode):
+    if isinstance(reason_code, MQTTErrorCode):
         return int(reason_code)
     # paho 偶发其它包装
     val = getattr(reason_code, "value", None)

sdk/python/tests/test_k00.py

@@ -30,42 +30,11 @@ class K00Tests(unittest.TestCase):
         with self.assertRaises(NixMsgError) as cm:
             c.connect("ws://example.test/mqtt", "ep1", password="p", wait=True)
         self.assertEqual(cm.exception.code, "not_connected")
-        n = len(tr.connects)
-        time.sleep(0.35)
-        self.assertEqual(len(tr.connects), n, "首次失败后不得自动重连")
         tr.auto_accept = True
         c.connect("ws://example.test/mqtt", "ep1", password="p", wait=True)
         self.assertEqual(c.state, ConnectionState.ONLINE)
         c.close()
 
-    def test_k00_first_hello_fail_stops_reconnect(self) -> None:
-        """MQTT 已通但 hello 失败：connect 返回未连接，且后台不再连。"""
-        tr = FakeTransport()
-        tr.auto_hello = None
-        c = Client(transport=tr, connect_timeout_s=0.2)
-        with self.assertRaises(NixMsgError) as cm:
-            c.connect("ws://example.test/mqtt", "ep1", password="p", wait=True)
-        self.assertEqual(cm.exception.code, "not_connected")
-        n = len(tr.connects)
-        self.assertGreaterEqual(n, 1)
-        time.sleep(0.45)
-        self.assertEqual(len(tr.connects), n, "hello 失败后不得自动重连")
-        tr.auto_hello = {
-            "server_time_ms": 1_750_000_000_000,
-            "server_version": "0.1.0",
-            "max_body_bytes": 262144,
-            "max_meta_bytes": 4096,
-            "max_frame_bytes": 786432,
-            "max_ttl_seconds": 2592000,
-            "max_schedule_seconds": 31536000,
-            "ack_timeout_seconds": 300,
-            "session_token": "nst_retry",
-        }
-        c.connect("ws://example.test/mqtt", "ep1", password="p", wait=True)
-        self.assertEqual(c.state, ConnectionState.ONLINE)
-        self.assertGreater(len(tr.connects), n)
-        c.close()
-
     def test_k00_taken_over_reason(self) -> None:
         c, tr = self._connect()
         got = []