fix(worker,ui): block cancelling a task while its unit merge is draining

TaskStateService.CancelAsync allowed cancelling a WaitingForReview task even while PlanningMergeOrchestrator was mid-drain on it: ApproveReview awaits the whole multi-subtask merge synchronously, so a concurrent CancelReview (UI or MCP) could flip the parent to Cancelled while the orchestrator kept merging children onto the target branch, then FinalizeParentDoneAsync would find the parent no longer WaitingForReview and give up - leaving the merged diffs stranded with no rollback. CancelAsync now rejects with a clear reason when HasActiveMerge(taskId) is true. TaskStateService can't take PlanningMergeOrchestrator as a direct constructor dependency (circular back to ITaskStateService), so it takes a lazily-resolved Func<IActiveMergeState> instead, mirroring the existing Func<ITaskStateService> cycle-break already used for PlanningChainCoordinator. UI polish: DetailsIslandViewModel.IsMergeDraining gates CancelReviewCommand's CanExecute (same shape as WorktreesOverviewModalViewModel.IsMerging), and the command's catch now raises ErrorReported instead of swallowing the rejection silently.
2026-08-06 13:38:02 +02:00
parent 0d1e3b9a6f
commit 79f90a9a8e
10 changed files with 205 additions and 5 deletions
@@ -55,6 +55,7 @@ public abstract class StubWorkerClient : IWorkerClient
    public void RaiseHandoffRequested(string taskId, IReadOnlyList<string> survivingTaskIds) => HandoffRequestedEvent?.Invoke(taskId, survivingTaskIds);
    public void RaisePlanningMergeConflict(string planningTaskId, string subtaskId, IReadOnlyList<string> files, bool externallyDriven)
        => PlanningMergeConflictEvent?.Invoke(planningTaskId, subtaskId, files, externallyDriven);
+    public void RaisePlanningMergeStarted(string planningTaskId, string targetBranch) => PlanningMergeStartedEvent?.Invoke(planningTaskId, targetBranch);
    public void RaisePlanningMergeAborted(string planningTaskId) => PlanningMergeAbortedEvent?.Invoke(planningTaskId);
    public void RaisePlanningCompleted(string planningTaskId) => PlanningCompletedEvent?.Invoke(planningTaskId);

@@ -161,4 +161,69 @@ public class DetailsIslandReviewActionsTests : IDisposable

        Assert.Equal(worker.ExceptionMessage, reportedError);
    }
+
+    [Fact]
+    public void CancelReview_IsDisabled_WhileUnitMergeIsDraining()
+    {
+        var worker = new RecordingWorkerClient();
+        var vm = BuildVm(worker);
+        vm.Bind(new TaskRowViewModel { Id = "task-drain-1", Status = TaskStatus.WaitingForReview });
+
+        Assert.True(vm.CancelReviewCommand.CanExecute(null));
+
+        worker.RaisePlanningMergeStarted("task-drain-1", "main");
+        Assert.False(vm.CancelReviewCommand.CanExecute(null));
+
+        worker.RaisePlanningCompleted("task-drain-1");
+        Assert.True(vm.CancelReviewCommand.CanExecute(null));
+    }
+
+    [Fact]
+    public void CancelReview_ReDisables_UntilMergeAborted()
+    {
+        var worker = new RecordingWorkerClient();
+        var vm = BuildVm(worker);
+        vm.Bind(new TaskRowViewModel { Id = "task-drain-2", Status = TaskStatus.WaitingForReview });
+
+        worker.RaisePlanningMergeStarted("task-drain-2", "main");
+        Assert.False(vm.CancelReviewCommand.CanExecute(null));
+
+        worker.RaisePlanningMergeAborted("task-drain-2");
+        Assert.True(vm.CancelReviewCommand.CanExecute(null));
+    }
+
+    [Fact]
+    public void CancelReview_UnaffectedByMergeEvents_ForADifferentTask()
+    {
+        var worker = new RecordingWorkerClient();
+        var vm = BuildVm(worker);
+        vm.Bind(new TaskRowViewModel { Id = "task-drain-3", Status = TaskStatus.WaitingForReview });
+
+        worker.RaisePlanningMergeStarted("some-other-parent", "main");
+
+        Assert.True(vm.CancelReviewCommand.CanExecute(null));
+    }
+
+    private sealed class ThrowingCancelWorkerClient : StubWorkerClient
+    {
+        public override bool IsConnected => true;
+        public string ExceptionMessage { get; init; } =
+            "A merge is in progress for this task; wait for it to finish before cancelling.";
+        public override Task CancelReviewAsync(string taskId) => throw new Exception(ExceptionMessage);
+    }
+
+    [Fact]
+    public async Task CancelReview_WhenWorkerThrows_RaisesErrorReported()
+    {
+        var worker = new ThrowingCancelWorkerClient();
+        var vm = BuildVm(worker);
+        vm.Bind(new TaskRowViewModel { Id = "task-cancel-err-1", Status = TaskStatus.WaitingForReview });
+
+        string? reportedError = null;
+        vm.ErrorReported += msg => reportedError = msg;
+
+        await vm.CancelReviewCommand.ExecuteAsync(null);
+
+        Assert.Equal(worker.ExceptionMessage, reportedError);
+    }
 }