fix: 修复停机后连接等待与首次注册竞态

CHANGELOG.md

@@ -6,6 +6,7 @@
 ## [Unreleased]
 
 ### 修复
+- **终态连接等待（[#65](https://github.com/CSJ608/StreamFrame/issues/65)）**：取得连接等待器后复查停机状态，关闭首次注册与 Shutdown 的竞态；Dispose 或生命周期取消后的新等待也以任务取消结束，无需调用方令牌。补充终态调用、1000 次首次注册竞速及调用方取消隔离回归。
 - **坏头后完整帧交付（[#64](https://github.com/CSJ608/StreamFrame/issues/64)）**：定界器返回 false 但已消费无效前缀时继续解析现有缓冲，无进展才等待输入；保留非法长度头四字节丢弃策略，避免完整帧挂起及误触发半帧超时。补充推进契约及连续坏头、粘包、半帧、EOF、自定义定界器和错误元数据回归。
 - **监听绑定失败恢复（[#63](https://github.com/CSJ608/StreamFrame/issues/63)）**：监听 Socket 完成配置、Bind/Listen 后才发布，失败释放并保持字段为空，端口释放后可自动重试接入；发布与停机释放互斥，保留接受循环代次及单客户端监听关闭语义。新增同步信号门控的端口占用恢复、双向消息及取消/Dispose 竞态回归。
 - **Soak 目标矩阵（[#66](https://github.com/CSJ608/StreamFrame/issues/66)）**：显式选择 Ubuntu net8.0/net10.0、Windows net8.0/net10.0/net48，避免 Ubuntu 启动 .NET Framework 测试；job 名、详细日志与始终尝试上传的 TRX 产物按 OS/TFM 区分，测试断言失败继续使 job 失败。普通 CI 必需检查名不变。

src/StreamFrame/Connection/StreamConnection.cs

@@ -1074,10 +1074,18 @@ public void Fault(Exception exception)
     /// <inheritdoc />
     public Task WaitForConnectedAsync(CancellationToken ct = default)
     {
-        if (State == ConnectionState.Connected)
+        if (!IsDisposed && State == ConnectionState.Connected)
             return Task.CompletedTask;
 
         var tcs = GetOrCreateWhenConnected();
+        // 必须在注册后复查：Shutdown 可能已清空旧等待器，随后本次才发布新等待器。
+        // 若终态发生在复查之后，Shutdown 会取得已发布的等待器并负责取消。
+        if (IsDisposed)
+        {
+            tcs.TrySetCanceled();
+            return tcs.Task;
+        }
+
         return State == ConnectionState.Connected
             ? Task.CompletedTask // 获取等待器的间隙恰好连上了
             : tcs.Task.WaitAsync(ct);

test/StreamFrame.Tests/ConnectionUsabilityTests.cs

@@ -40,11 +40,12 @@ public async Task WaitForConnectedAsync_CompletesWhenConnectionEstablished()
         await using var server = CreateConnection(port, isActive: false);
 
         client.Start(CancellationToken.None);
+        var pending = client.WaitForConnectedAsync();
         // 服务端稍后才启动：等待者必须跨过若干次连接失败重试
         await Task.Delay(400);
         server.Start(CancellationToken.None);
 
-        await client.WaitForConnectedAsync().WaitAsync(TimeSpan.FromSeconds(5));
+        await pending.WaitAsync(TimeSpan.FromSeconds(5));
         await server.WaitForConnectedAsync().WaitAsync(TimeSpan.FromSeconds(5));
         Assert.Equal(ConnectionState.Connected, client.State);
     }
@@ -93,6 +94,74 @@ public async Task WaitForConnectedAsync_Dispose_CancelsPendingWaiter()
         await Assert.ThrowsAnyAsync<OperationCanceledException>(() => waitTask);
     }
 
+    [Fact]
+    public async Task WaitForConnectedAsync_AfterDispose_IsCanceled()
+    {
+        await using var client = CreateConnection(12345, isActive: true);
+        await client.DisposeAsync();
+
+        var wait = client.WaitForConnectedAsync();
+        Assert.True(wait.IsCanceled);
+        await Assert.ThrowsAnyAsync<OperationCanceledException>(() => wait);
+    }
+
+    [Fact]
+    public async Task WaitForConnectedAsync_FirstRegistrationRacesDispose_NoOrphanedWaiter()
+    {
+        for (var iteration = 0; iteration < 1000; iteration++)
+        {
+            await using var client = CreateConnection(12345, isActive: true);
+            using var start = new Barrier(2);
+            Task? wait = null;
+            var register = Task.Run(() =>
+            {
+                Assert.True(start.SignalAndWait(TimeSpan.FromSeconds(5)));
+                wait = client.WaitForConnectedAsync();
+            });
+            var shutdown = Task.Run(async () =>
+            {
+                Assert.True(start.SignalAndWait(TimeSpan.FromSeconds(5)));
+                await client.DisposeAsync();
+            });
+            await Task.WhenAll(register, shutdown).WaitAsync(TimeSpan.FromSeconds(10));
+            Assert.NotNull(wait);
+            // net48 的 WaitAsync 兼容包装通过异步延续传播取消，必须等待传播完成。
+            await Assert.ThrowsAnyAsync<OperationCanceledException>(
+                () => wait.WaitAsync(TimeSpan.FromSeconds(5)));
+            Assert.True(wait.IsCanceled);
+        }
+    }
+
+    [Fact]
+    public async Task WaitForConnectedAsync_CallerCancellation_DoesNotCancelSharedWaiter()
+    {
+        await using var client = CreateConnection(12345, isActive: true);
+        using var caller = new CancellationTokenSource();
+        var shared = client.WaitForConnectedAsync();
+        var canceled = client.WaitForConnectedAsync(caller.Token);
+        caller.Cancel();
+        await Assert.ThrowsAnyAsync<OperationCanceledException>(() => canceled);
+        Assert.False(shared.IsCompleted);
+        await client.DisposeAsync();
+        await Assert.ThrowsAnyAsync<OperationCanceledException>(
+            () => shared.WaitAsync(TimeSpan.FromSeconds(5)));
+        Assert.True(shared.IsCanceled);
+    }
+
+    [Fact]
+    public async Task WaitForConnectedAsync_LifetimeCancellation_CancelsExistingAndFutureWaiters()
+    {
+        await using var client = CreateConnection(GetFreePort(), isActive: true);
+        using var lifetime = new CancellationTokenSource();
+        client.Start(lifetime.Token);
+        var wait = client.WaitForConnectedAsync();
+        lifetime.Cancel();
+        await Assert.ThrowsAnyAsync<OperationCanceledException>(
+            () => wait.WaitAsync(TimeSpan.FromSeconds(5)));
+        Assert.True(wait.IsCanceled);
+        Assert.True(client.WaitForConnectedAsync().IsCanceled);
+    }
+
     [Fact]
     public async Task Start_SecondCall_ThrowsInvalidOperation()
     {