fix(twincat): probe recycle honors cancellation — no uncancellable gate wait (05/STAB-12 compounded part); B6 complete (TwinCAT suite 189 green)

2026-07-13 12:43:06 -04:00
parent 082ee99b6b
commit 502a327f25
3 changed files with 48 additions and 7 deletions
@@ -328,6 +328,42 @@ public sealed class TwinCATReconnectReplayTests
        factory.Clients[1].Notifications.ShouldBeEmpty("the fresh handle must be disposed — no orphan ADS notification");
    }

+    /// <summary>
+    ///     STAB-12 (compounded part): <c>RecycleClientAsync</c> must honor cancellation — it must
+    ///     take the probe token into <c>ConnectGate.WaitAsync(ct)</c> rather than
+    ///     <c>CancellationToken.None</c>, so a shutdown mid-recycle (or a connect wedged under the
+    ///     gate) can't hang the probe loop uncancellably. Verified white-box: with the gate held and
+    ///     a cancelled token, the call must throw promptly rather than block forever.
+    /// </summary>
+    [Fact]
+    public async Task RecycleClient_HonorsCancellation()
+    {
+        var (drv, _) = NewNativeDriver(
+            tags: new TwinCATTagDefinition("X", Host, "MAIN.X", TwinCATDataType.DInt));
+        await drv.InitializeAsync("{}", TestContext.Current.CancellationToken);
+
+        // Reach the single configured device + wedge its ConnectGate so a recycle must wait on it.
+        var devicesField = typeof(TwinCATDriver).GetField("_devices",
+            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
+        var devicesObj = devicesField.GetValue(drv)!;
+        var values = (System.Collections.IEnumerable)devicesObj.GetType().GetProperty("Values")!.GetValue(devicesObj)!;
+        var device = (TwinCATDriver.DeviceState)values.Cast<object>().First();
+        await device.ConnectGate.WaitAsync(TestContext.Current.CancellationToken);
+
+        var recycle = typeof(TwinCATDriver).GetMethod("RecycleClientAsync",
+            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)!;
+
+        using var cts = new CancellationTokenSource();
+        await cts.CancelAsync();
+        var task = (Task)recycle.Invoke(drv, [device, cts.Token])!;
+
+        // Must throw promptly (cancelled token), NOT hang on the held gate. The 2 s bound turns an
+        // uncancellable-wait regression into a failure rather than a hung suite.
+        await Should.ThrowAsync<OperationCanceledException>(async () => await task.WaitAsync(TimeSpan.FromSeconds(2)));
+
+        device.ConnectGate.Release();
+    }
+
    private static async Task WaitForAsync(Func<bool> condition, TimeSpan timeout)
    {
        var deadline = DateTime.UtcNow + timeout;