fix(openai-ws): track pending passthrough turns

backend/internal/service/openai_ws_v2/passthrough_relay.go

@@ -538,7 +538,7 @@ func runUpstreamToClient(
 			// the upstream has started a Responses turn, success still requires a
 			// terminal protocol event. Treat an early 1000/EOF as a relay failure so
 			// the adapter does not report relay_completed with an active turn.
-			if graceful && openAIWSRelayActiveTurnID(state) != "" {
+			if graceful && state.hasUnfinishedTurn() {
 				graceful = false
 				err = errors.New("upstream websocket closed before terminal event: " + err.Error())
 			}
@@ -585,7 +585,14 @@ func runUpstreamToClient(
 			}
 			observedEvent = observeUpstreamMessage(state, payload, startAt, nowFn, onUsageParseFailure)
 		case coderws.MessageBinary:
-			// binary frame 直接透传，不进入 JSON 观测路径（避免无效解析开销）。
+			// Binary frames remain opaque for usage/result observation, but a JSON
+			// terminal still settles relay lifecycle. Otherwise the pending-turn
+			// disconnect guard would turn an already-delivered terminal into a false
+			// missing-terminal failure when the upstream closes normally.
+			if isTerminalEvent(strings.TrimSpace(gjson.GetBytes(payload, "type").String())) {
+				state.consumePendingTurnStartedAt()
+				openAIWSRelayDiscardActiveTurnTiming(state)
+			}
 		}
 		emitTurnComplete(onTurnComplete, state, observedEvent)
 		if dropDownstreamWrites != nil && dropDownstreamWrites.Load() {
@@ -995,6 +1002,13 @@ func (s *relayState) consumePendingTurnStartedAt() time.Time {
 	return *startedAt
 }
 
+func (s *relayState) hasUnfinishedTurn() bool {
+	if s == nil {
+		return false
+	}
+	return s.pendingTurnStart.Load() != nil || s.activeTurn != nil
+}
+
 func openAIWSRelayDeleteTurnTiming(state *relayState, responseID string) (relayTurnTiming, bool) {
 	if state == nil || state.turnTimingByID == nil {
 		return relayTurnTiming{}, false

backend/internal/service/openai_ws_v2/passthrough_relay_test.go

@@ -309,11 +309,46 @@ func TestRelay_UpstreamDisconnect(t *testing.T) {
 	defer cancel()
 
 	result, relayExit := Relay(ctx, clientConn, upstreamConn, firstPayload, RelayOptions{})
-	// 上游 EOF 属于 disconnect，标记为 graceful
-	require.Nil(t, relayExit, "上游 EOF 应被视为 graceful disconnect")
+	require.NotNil(t, relayExit)
+	require.Equal(t, "read_upstream", relayExit.Stage)
+	require.False(t, relayExit.Graceful)
+	require.ErrorContains(t, relayExit.Err, "upstream websocket closed before terminal event")
 	require.Equal(t, "gpt-4o", result.RequestModel)
 }
 
+func TestRelay_UpstreamNormalCloseBeforeResponseIDIsFailure(t *testing.T) {
+	t.Parallel()
+
+	clientConn := newPassthroughTestFrameConn(nil, false)
+	upstreamConn := &eofReplacementFrameConn{
+		FrameConn: newPassthroughTestFrameConn([]passthroughTestFrame{
+			{
+				msgType: coderws.MessageText,
+				payload: []byte(`{"type":"response.created","status":"in_progress"}`),
+			},
+			{
+				msgType: coderws.MessageText,
+				payload: []byte(`{"type":"response.in_progress","status":"in_progress"}`),
+			},
+		}, true),
+		err: coderws.CloseError{Code: coderws.StatusNormalClosure},
+	}
+
+	firstPayload := []byte(`{"type":"response.create","model":"gpt-5.6-sol","input":[]}`)
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	result, relayExit := Relay(ctx, clientConn, upstreamConn, firstPayload, RelayOptions{})
+	require.NotNil(t, relayExit)
+	require.Equal(t, "read_upstream", relayExit.Stage)
+	require.False(t, relayExit.Graceful)
+	require.True(t, relayExit.WroteDownstream)
+	require.ErrorContains(t, relayExit.Err, "upstream websocket closed before terminal event")
+	require.Empty(t, result.RequestID)
+	require.Empty(t, result.TerminalEventType)
+	require.Len(t, clientConn.Writes(), 2)
+}
+
 func TestRelay_UpstreamNormalCloseBeforeTerminalIsFailure(t *testing.T) {
 	t.Parallel()
 
@@ -921,7 +956,10 @@ func TestRelay_BinaryFramePassthrough(t *testing.T) {
 	defer cancel()
 
 	result, relayExit := Relay(ctx, clientConn, upstreamConn, firstPayload, RelayOptions{})
-	require.Nil(t, relayExit)
+	require.NotNil(t, relayExit)
+	require.Equal(t, "read_upstream", relayExit.Stage)
+	require.False(t, relayExit.Graceful)
+	require.ErrorContains(t, relayExit.Err, "upstream websocket closed before terminal event")
 	// binary frame 不解析 usage
 	require.Equal(t, 0, result.Usage.InputTokens)
 
@@ -986,7 +1024,12 @@ func TestRelay_PreservesFirstMessageType(t *testing.T) {
 	t.Parallel()
 
 	clientConn := newPassthroughTestFrameConn(nil, false)
-	upstreamConn := newPassthroughTestFrameConn(nil, true)
+	upstreamConn := newPassthroughTestFrameConn([]passthroughTestFrame{
+		{
+			msgType: coderws.MessageBinary,
+			payload: []byte(`{"type":"response.completed","response":{"id":"resp_binary_first_type"}}`),
+		},
+	}, true)
 
 	firstPayload := []byte(`{"type":"response.create","model":"gpt-4o","input":[]}`)
 	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
@@ -1001,6 +1044,9 @@ func TestRelay_PreservesFirstMessageType(t *testing.T) {
 	require.Len(t, upstreamWrites, 1)
 	require.Equal(t, coderws.MessageBinary, upstreamWrites[0].msgType)
 	require.Equal(t, firstPayload, upstreamWrites[0].payload)
+	clientWrites := clientConn.Writes()
+	require.Len(t, clientWrites, 1)
+	require.Equal(t, coderws.MessageBinary, clientWrites[0].msgType)
 }
 
 func TestRelay_UsageParseFailureDoesNotBlockRelay(t *testing.T) {