fix(merge): pass the stash consent to the conflict resolver so it opens on a dirty target

The resolver restarts the merge via StartConflictMerge, which had no autostash.
After a stash-retry approve reported 'conflict', the restart hit the same dirty
target, got 'dirty_target' and the resolver silently never opened. Thread the
consent through the hub, client, coordinator and resolver; surface a refusal in
the footer instead of dropping it.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docs/explore-notes/review-merge.md

@@ -252,6 +252,11 @@ Single-task mode starts the conflict merge, then parses each conflicted file int
 conflict `MergeFileSegment`s via the worker's `GetMergeConflictDocuments`. Types live in
 `ConflictModels`: `MergeFile` / `MergeFileSegment` / `MergeConflictBlock`.
 
+⚠️ **The resolver restarts the merge itself** (`StartConflictMerge`, `leaveConflictsInTree`), so the caller's
+`autostash` consent must travel with it (`MergeCoordinator.ResolveConflictAsync(..., autostash)` →
+`OpenAsync(target, autostash)` → hub). Without it a dirty target answers `dirty_target`, the
+resolver stays closed after the stash-retry approve already reported `conflict`.
+
 Exposed per active file: `ActiveOursText` / `ActiveResultText` / `ActiveTheirsText`
 (reconstructed from `MergeFile.OursText/ResultText/TheirsText`; Result seeds unresolved
 conflicts with Ours), plus `ActiveFile` / `SelectFileCommand` (multi-file switcher),

src/ClaudeDo.Ui/Services/Interfaces/IWorkerClient.cs

@@ -136,7 +136,7 @@ public interface IWorkerClient : INotifyPropertyChanged
     Task CancelReviewAsync(string taskId);
 
     // ── Conflict resolution (worker hub side implemented by Layer C) ──
-    Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch);
+    Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch, bool autostash = false);
     Task<MergeConflictDocumentsDto> GetMergeConflictDocumentsAsync(string taskId);
     Task WriteConflictResolutionAsync(string taskId, string path, string resolvedContent);
     Task<MergeResultDto> ContinueConflictMergeAsync(string taskId);

src/ClaudeDo.Ui/Services/MergeCoordinator.cs

@@ -14,8 +14,10 @@ namespace ClaudeDo.Ui.Services;
 public sealed class MergeCoordinator
 {
     /// Set once at composition to the shell's resolver entry. Null (headless/tests) ⇒ no-op.
-    public Func<string, string, Task>? Handler { get; set; }
+    public Func<string, string, bool, Task>? Handler { get; set; }
 
-    public Task ResolveConflictAsync(string taskId, string targetBranch) =>
-        Handler?.Invoke(taskId, targetBranch) ?? Task.CompletedTask;
+    /// <summary>Opens the resolver for <paramref name="taskId"/>; <paramref name="autostash"/> is the
+    /// caller's stash consent, repeated because the resolver restarts the merge on its own.</summary>
+    public Task ResolveConflictAsync(string taskId, string targetBranch, bool autostash = false) =>
+        Handler?.Invoke(taskId, targetBranch, autostash) ?? Task.CompletedTask;
 }

src/ClaudeDo.Ui/Services/WorkerClient.cs

@@ -399,8 +399,8 @@ public partial class WorkerClient : ObservableObject, IAsyncDisposable, IWorkerC
             "MergeTask", taskId, targetBranch, removeWorktree, commitMessage, autostash));
     }
 
-    public Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch)
-        => InvokeTimedAsync<MergeResultDto>("StartConflictMerge", () => _hub.InvokeAsync<MergeResultDto>("StartConflictMerge", taskId, targetBranch));
+    public Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch, bool autostash = false)
+        => InvokeTimedAsync<MergeResultDto>("StartConflictMerge", () => _hub.InvokeAsync<MergeResultDto>("StartConflictMerge", taskId, targetBranch, autostash));
 
     public Task<MergeConflictDocumentsDto> GetMergeConflictDocumentsAsync(string taskId)
         => InvokeTimedAsync<MergeConflictDocumentsDto>("GetMergeConflictDocuments", () => _hub.InvokeAsync<MergeConflictDocumentsDto>("GetMergeConflictDocuments", taskId));

src/ClaudeDo.Ui/ViewModels/Conflicts/ConflictResolverViewModel.cs

@@ -133,14 +133,15 @@ public sealed partial class ConflictResolverViewModel : ObservableObject
     }
 
     /// <summary>Starts the conflict merge and loads the conflicted files as line-level segments.
-    /// Returns true when there is something to resolve (caller should show the dialog).</summary>
-    public async Task<bool> OpenAsync(string targetBranch)
+    /// Returns true when there is something to resolve (caller should show the dialog).
+    /// <paramref name="autostash"/> carries the caller's stash consent: a dirty target is otherwise refused.</summary>
+    public async Task<bool> OpenAsync(string targetBranch, bool autostash = false)
     {
         IsBusy = true;
         Error = null;
         try
         {
-            var start = await _worker.StartConflictMergeAsync(_taskId, targetBranch);
+            var start = await _worker.StartConflictMergeAsync(_taskId, targetBranch, autostash);
             if (!string.Equals(start.Status, "conflict", StringComparison.Ordinal))
             {
                 // Any non-conflict outcome here means nothing was left mid-merge for this dialog

src/ClaudeDo.Ui/ViewModels/Islands/DetailsIslandViewModel.cs

@@ -1295,9 +1295,11 @@ public sealed partial class DetailsIslandViewModel : ViewModelBase, IDisposable
             // Nothing landed -- the target working dir has uncommitted changes (often another
             // session's WIP in the shared main checkout). Offer the one-shot stash retry; git
             // restores the changes itself once the merge is through.
+            var stashed = false;
             if (result?.Status == "dirty_target" && Dialogs != null
                 && await Dialogs.ConfirmAsync(Loc.T("vm.detailsIsland.stashAndMergeConfirm")))
             {
+                stashed = true;
                 ApproveOp.Report(Loc.T("ops.merge.merging"));
                 result = await _worker.ApproveReviewAsync(
                     taskId, Merge.SelectedMergeTarget ?? "", autostash: true);
@@ -1306,7 +1308,7 @@ public sealed partial class DetailsIslandViewModel : ViewModelBase, IDisposable
             if (result?.Status == "dirty_target" && Dialogs != null)
                 await Dialogs.ShowErrorAsync(result.ErrorMessage ?? Loc.T("vm.detailsIsland.dirtyTarget"));
             else if (!hasChildren && result?.Status == "conflict")
-                await _merge.ResolveConflictAsync(taskId, Merge.SelectedMergeTarget ?? "");
+                await _merge.ResolveConflictAsync(taskId, Merge.SelectedMergeTarget ?? "", stashed);
             // The merge itself already landed; the verify command failed, so the task stayed
             // out of Done. Surface that instead of silently looking like nothing happened.
             else if (!hasChildren && result?.Status == "verify_failed" && Dialogs != null)

src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs

@@ -109,13 +109,15 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
         BringToFront?.Invoke();
     }
 
-    public async Task RequestConflictResolutionAsync(string taskId, string targetBranch)
+    public async Task RequestConflictResolutionAsync(string taskId, string targetBranch, bool autostash = false)
     {
         if (ConflictResolverFactory is null || Dialogs is null) return;
         var vm = ConflictResolverFactory(taskId);
-        var hasConflicts = await vm.OpenAsync(targetBranch);
+        var hasConflicts = await vm.OpenAsync(targetBranch, autostash);
         if (hasConflicts)
             await Dialogs.ShowConflictResolverAsync(vm);
+        else if (vm.Error is { } error)
+            FlashFooterError(error);
     }
 
     [ObservableProperty] private bool _isUpdateBannerVisible;

src/ClaudeDo.Ui/ViewModels/Modals/MergeModalViewModel.cs

@@ -139,7 +139,7 @@ public sealed partial class MergeModalViewModel : ViewModelBase
                     // which re-starts the merge leaving conflicts in the tree.
                     RoutedToResolver = true;
                     CloseAction?.Invoke();
-                    await _merge.ResolveConflictAsync(TaskId, SelectedBranch!);
+                    await _merge.ResolveConflictAsync(TaskId, SelectedBranch!, autostash);
                     break;
                 case "blocked":
                     ErrorMessage = Loc.T("vm.merge.blocked", result.ErrorMessage ?? "");

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -543,12 +543,12 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
             return new MergePreviewDto(p.Status, p.ConflictFiles, p.ChangedFileCount);
         });
 
-    public Task<MergeResultDto> StartConflictMerge(string taskId, string targetBranch)
+    public Task<MergeResultDto> StartConflictMerge(string taskId, string targetBranch, bool autostash = false)
         => HubGuard(async () =>
         {
             var r = await _mergeService.MergeAsync(
                 taskId, targetBranch ?? "", removeWorktree: false, commitMessage: "",
-                leaveConflictsInTree: true, CancellationToken.None);
+                leaveConflictsInTree: true, CancellationToken.None, autostash: autostash);
             if (r.Status == TaskMergeService.StatusBlocked)
                 throw new HubException(r.ErrorMessage ?? "merge blocked");
             return new MergeResultDto(r.Status, r.ConflictFiles, r.ErrorMessage);

tests/ClaudeDo.Ui.Tests/IslandsShellViewModelExternalMergeTests.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Threading.Tasks;
 using ClaudeDo.Data.Models;
+using ClaudeDo.Ui.Services;
 using ClaudeDo.Ui.ViewModels;
 using Xunit;
 
@@ -124,4 +125,26 @@ public class IslandsShellViewModelExternalMergeTests
         // click must degrade gracefully rather than throw, same as the existing UI-driven path.
         await vm.OpenExternalMergeConflictCommand.ExecuteAsync(null);
     }
+
+    private sealed class DirtyTargetWorker : StubWorkerClient
+    {
+        public override Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch, bool autostash = false) =>
+            Task.FromResult(new MergeResultDto("dirty_target", Array.Empty<string>(), "target working tree has uncommitted changes"));
+    }
+
+    [Fact]
+    public async Task RequestConflictResolution_ResolverRefused_ShowsWhyInTheFooter()
+    {
+        // Regression: a refusal (dirty target, ...) left the resolver closed with no explanation anywhere.
+        var vm = new IslandsShellViewModel
+        {
+            Dialogs = new RecordingDialogService(),
+            ConflictResolverFactory = id => new ClaudeDo.Ui.ViewModels.Conflicts.ConflictResolverViewModel(new DirtyTargetWorker(), id),
+        };
+
+        await vm.RequestConflictResolutionAsync("t1", "main");
+
+        Assert.Equal(WorkerLogLevel.Error, vm.WorkerLogLevel);
+        Assert.Contains("uncommitted changes", vm.WorkerLogText);
+    }
 }

tests/ClaudeDo.Ui.Tests/StubWorkerClient.cs

@@ -127,7 +127,7 @@ public abstract class StubWorkerClient : IWorkerClient
     public virtual Task RejectReviewToQueueAsync(string taskId, string feedback) => Task.CompletedTask;
     public virtual Task RejectReviewToIdleAsync(string taskId) => Task.CompletedTask;
     public virtual Task CancelReviewAsync(string taskId) => Task.CompletedTask;
-    public virtual Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch) => Task.FromResult(new MergeResultDto("conflict", System.Array.Empty<string>(), null));
+    public virtual Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch, bool autostash = false) => Task.FromResult(new MergeResultDto("conflict", System.Array.Empty<string>(), null));
     public virtual Task<MergeConflictDocumentsDto> GetMergeConflictDocumentsAsync(string taskId) => Task.FromResult(new MergeConflictDocumentsDto(taskId, System.Array.Empty<ConflictDocumentDto>()));
     public virtual Task WriteConflictResolutionAsync(string taskId, string path, string resolvedContent) => Task.CompletedTask;
     public virtual Task<MergeResultDto> ContinueConflictMergeAsync(string taskId) => Task.FromResult(new MergeResultDto("merged", System.Array.Empty<string>(), null));

tests/ClaudeDo.Ui.Tests/ViewModels/ConflictResolverViewModelTests.cs

@@ -30,9 +30,14 @@ public class ConflictResolverViewModelTests
         public string? ContinuedPlanningParent;
         public string? AbortedPlanningParent;
 
-        public override Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch)
+        /// <summary>Models a target working tree with uncommitted changes: refused unless the caller consented to the stash.</summary>
+        public bool DirtyTarget;
+
+        public override Task<MergeResultDto> StartConflictMergeAsync(string taskId, string targetBranch, bool autostash = false)
         {
             StartCalled = true;
+            if (DirtyTarget && !autostash)
+                return Task.FromResult(new MergeResultDto("dirty_target", System.Array.Empty<string>(), "target working tree has uncommitted changes"));
             return Task.FromResult(new MergeResultDto("conflict", new[] { "README.md" }, null));
         }
 
@@ -63,6 +68,19 @@ public class ConflictResolverViewModelTests
         public override Task AbortConflictMergeAsync(string taskId) { Aborted = true; return Task.CompletedTask; }
     }
 
+    [Fact]
+    public async Task OpenAsync_DirtyTarget_OpensOnlyWithStashConsent()
+    {
+        // Regression: a dirty target refused the resolver's own merge restart, so it never opened.
+        var refused = new ConflictResolverViewModel(new FakeWorker { DirtyTarget = true }, "task-1");
+        Assert.False(await refused.OpenAsync("main"));
+        Assert.Equal("target working tree has uncommitted changes", refused.Error);
+
+        var consented = new ConflictResolverViewModel(new FakeWorker { DirtyTarget = true }, "task-1");
+        Assert.True(await consented.OpenAsync("main", autostash: true));
+        Assert.Null(consented.Error);
+    }
+
     [Fact]
     public async Task OpenAsync_LoadsConflicts_AndBlocksContinueUntilResolved()
     {

tests/ClaudeDo.Ui.Tests/ViewModels/DetailsIslandConflictSeamTests.cs

@@ -60,7 +60,7 @@ public class DetailsIslandConflictSeamTests : IDisposable
         string? capturedTarget = null;
         var coordinator = new MergeCoordinator
         {
-            Handler = (tid, target) =>
+            Handler = (tid, target, _) =>
             {
                 capturedTaskId = tid;
                 capturedTarget = target;
@@ -77,4 +77,35 @@ public class DetailsIslandConflictSeamTests : IDisposable
         Assert.Equal(taskId, capturedTaskId);
         Assert.Equal("main", capturedTarget);
     }
+
+    /// <summary>Models the worker: a dirty target refuses the merge unless the caller consented to the stash.</summary>
+    private sealed class DirtyTargetConflictWorkerClient : StubWorkerClient
+    {
+        public override bool IsConnected => true;
+        public override Task<MergeResultDto?> ApproveReviewAsync(string taskId, string targetBranch, bool autostash = false) =>
+            Task.FromResult<MergeResultDto?>(autostash
+                ? new MergeResultDto("conflict", new[] { "a.cs" }, null)
+                : new MergeResultDto("dirty_target", Array.Empty<string>(), "target working tree has uncommitted changes"));
+    }
+
+    [Fact]
+    public async Task ApproveReview_StashRetryEndsInConflict_HandsTheStashConsentToTheResolver()
+    {
+        // Regression: the resolver restarts the merge itself; without the consent it hit the same
+        // dirty target, got "dirty_target" and silently never opened.
+        bool? capturedAutostash = null;
+        var coordinator = new MergeCoordinator
+        {
+            Handler = (_, _, autostash) => { capturedAutostash = autostash; return Task.CompletedTask; },
+        };
+
+        var vm = BuildVm(new DirtyTargetConflictWorkerClient(), coordinator);
+        vm.Dialogs = new RecordingDialogService { ConfirmResult = true };
+        vm.Bind(new TaskRowViewModel { Id = "task-dirty-1", Status = TaskStatus.WaitingForReview });
+        vm.Merge.SelectedMergeTarget = "main";
+
+        await vm.ApproveReviewCommand.ExecuteAsync(null);
+
+        Assert.True(capturedAutostash);
+    }
 }

tests/ClaudeDo.Ui.Tests/ViewModels/MergeModalViewModelTests.cs

@@ -26,6 +26,9 @@ public class MergeModalViewModelTests
         /// Result for a call with autostash=false; the autostash retry always merges.
         public MergeResultDto CleanResult { get; set; } = new("merged", new List<string>(), null);
 
+        /// Result for the autostash retry.
+        public MergeResultDto StashedResult { get; set; } = new("merged", new List<string>(), null);
+
         public override Task<MergeTargetsDto?> GetMergeTargetsAsync(string taskId) =>
             Task.FromResult(Targets);
 
@@ -36,7 +39,7 @@ public class MergeModalViewModelTests
             CapturedAutostash = autostash;
             return BlockMerge
                 ? MergeGate.Task
-                : Task.FromResult(autostash ? new MergeResultDto("merged", new List<string>(), null) : CleanResult);
+                : Task.FromResult(autostash ? StashedResult : CleanResult);
         }
     }
 
@@ -189,4 +192,26 @@ public class MergeModalViewModelTests
 
         Assert.Null(vm.ProgressMessage);
     }
+
+    [Fact]
+    public async Task Stash_retry_ending_in_conflict_hands_the_stash_consent_to_the_resolver()
+    {
+        // Regression: the resolver restarts the merge itself and needs the same consent, or the
+        // dirty target refuses it and the resolver never opens.
+        var worker = new Worker
+        {
+            CleanResult = new("dirty_target", new List<string>(), "uncommitted changes"),
+            StashedResult = new("conflict", new List<string> { "a.cs" }, null),
+        };
+        bool? capturedAutostash = null;
+        var vm = new MergeModalViewModel(worker, new MergeCoordinator
+        {
+            Handler = (_, _, autostash) => { capturedAutostash = autostash; return Task.CompletedTask; },
+        });
+        await vm.InitializeAsync("task-1", "do the thing");
+
+        await vm.StashAndMergeCommand.ExecuteAsync(null);
+
+        Assert.True(capturedAutostash);
+    }
 }

tests/ClaudeDo.Ui.Tests/ViewModels/WorktreesOverviewBatchMergeTests.cs

@@ -141,7 +141,7 @@ public class WorktreesOverviewBatchMergeTests
         (string Task, string Target)? captured = null;
         var coordinator = new ClaudeDo.Ui.Services.MergeCoordinator
         {
-            Handler = (taskId, target) => { captured = (taskId, target); return System.Threading.Tasks.Task.CompletedTask; },
+            Handler = (taskId, target, _) => { captured = (taskId, target); return System.Threading.Tasks.Task.CompletedTask; },
         };
         var vm = NewVm(coordinator);
         vm.SelectedTarget = "release";

tests/ClaudeDo.Worker.Tests/Services/TaskMergeServiceTests.cs

@@ -1567,6 +1567,50 @@ public class TaskMergeServiceTests : IDisposable
         GitRepoFixture.RunGit(repo.RepoDir, "merge", "--abort");
     }
 
+    [Fact]
+    public async Task MergeAsync_LeaveConflicts_DirtyTarget_NeedsAutostashAndAbortRestoresTheChanges()
+    {
+        // The resolver restarts the merge via leaveConflictsInTree; on a dirty target that only
+        // works with the caller's stash consent, and git hands the stash back on abort.
+        if (!GitRepoFixture.IsGitAvailable()) return;
+
+        var db = NewDb();
+        var repo = NewRepo();
+        GitRepoFixture.RunGit(repo.RepoDir, "branch", "-m", "main");
+
+        File.WriteAllText(Path.Combine(repo.RepoDir, "README.md"), "# main change\n");
+        File.WriteAllText(Path.Combine(repo.RepoDir, "other.txt"), "tracked\n");
+        GitRepoFixture.RunGit(repo.RepoDir, "add", "-A");
+        GitRepoFixture.RunGit(repo.RepoDir, "commit", "-m", "main change");
+
+        var wtPath = Path.Combine(Path.GetTempPath(), $"wt_{Guid.NewGuid():N}");
+        _wtCleanups.Add((repo.RepoDir, wtPath));
+        GitRepoFixture.RunGit(repo.RepoDir, "worktree", "add", "-b", "claudedo/t1", wtPath, repo.BaseCommit);
+        File.WriteAllText(Path.Combine(wtPath, "README.md"), "# branch change\n");
+        GitRepoFixture.RunGit(wtPath, "commit", "-am", "branch change");
+
+        var (_, task) = await SeedListAndTask(db, workingDir: repo.RepoDir, status: TaskStatus.WaitingForReview);
+        await SeedWorktree(db, task.Id, wtPath, "claudedo/t1", repo.BaseCommit);
+
+        File.WriteAllText(Path.Combine(repo.RepoDir, "other.txt"), "dirty\n");
+
+        var (svc, _) = BuildService(db);
+
+        var refused = await svc.MergeAsync(task.Id, "main", false, "msg", leaveConflictsInTree: true, CancellationToken.None);
+        Assert.Equal(TaskMergeService.StatusDirtyTarget, refused.Status);
+
+        var result = await svc.MergeAsync(
+            task.Id, "main", false, "msg", leaveConflictsInTree: true, CancellationToken.None, autostash: true);
+        Assert.Equal(TaskMergeService.StatusConflict, result.Status);
+        Assert.Contains("README.md", result.ConflictFiles);
+        Assert.True(await new GitService().IsMidMergeAsync(repo.RepoDir));
+
+        await svc.AbortMergeAsync(task.Id, CancellationToken.None);
+
+        Assert.False(await new GitService().IsMidMergeAsync(repo.RepoDir));
+        Assert.Equal("dirty\n", File.ReadAllText(Path.Combine(repo.RepoDir, "other.txt")).Replace("\r\n", "\n"));
+    }
+
     [Fact]
     public async Task WriteResolutionAsync_ThenContinue_CompletesMerge()
     {