feat(worker): record merge commit SHA and add revert_merge tool

Persists the merge commit SHA on WorktreeEntity for every successful single-task and unit merge, and adds a TaskMergeService.RevertMergeAsync + revert_merge MCP tool that undoes a merged task's merge via `git revert -m 1` (never reset/rewrite, since the target checkout is shared). Rejects cleanly when there's no recorded SHA, the repo is mid-merge/mid-revert, or the target has foreign uncommitted changes; a conflicting revert aborts immediately. Also exposes the new mergeCommit field via get_task_worktree.
2026-08-05 11:46:51 +02:00
parent 6c5acd09b9
commit 10e561f336
14 changed files with 1452 additions and 14 deletions
@@ -624,6 +624,39 @@ public sealed class ExternalMcpServiceTests : IDisposable
        Assert.False(info.IsDirty);
    }

+    [Fact]
+    public async Task GetTaskWorktree_BeforeMerge_MergeCommitIsNull()
+    {
+        if (!GitAvailable) { Assert.True(true, "git not available -- skipping"); return; }
+
+        var (task, _, _) = await SeedWorktreeAsync();
+        var sut = BuildSut(CreateQueue());
+
+        var info = await sut.GetTaskWorktree(task.Id, CancellationToken.None);
+
+        Assert.Null(info.MergeCommit);
+    }
+
+    [Fact]
+    public async Task GetTaskWorktree_AfterMerge_ExposesMergeCommit()
+    {
+        if (!GitAvailable) { Assert.True(true, "git not available -- skipping"); return; }
+
+        var (task, list, wt) = await SeedWorktreeAsync(TaskStatus.Done);
+        File.WriteAllText(Path.Combine(wt.WorktreePath, "added.txt"), "new\n");
+        GitRepoFixture.RunGit(wt.WorktreePath, "add", "-A");
+        GitRepoFixture.RunGit(wt.WorktreePath, "commit", "-m", "feat: add file");
+
+        var target = await new GitService().GetCurrentBranchAsync(list.WorkingDir!, CancellationToken.None);
+        var sut = BuildSut(CreateQueue());
+        await sut.MergeTask(task.Id, target, true, false, false, cancellationToken: CancellationToken.None);
+
+        var info = await sut.GetTaskWorktree(task.Id, CancellationToken.None);
+
+        var expected = GitRepoFixture.RunGit(list.WorkingDir!, "rev-parse", "HEAD").Trim();
+        Assert.Equal(expected, info.MergeCommit);
+    }
+
    // ── GetTaskDiff ────────────────────────────────────────────────────────────

    [Fact]
@@ -1136,6 +1169,78 @@ public sealed class ExternalMcpServiceTests : IDisposable
        Assert.Contains("mid-merge", ex.Message);
    }

+    // ── RevertMerge ────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task RevertMerge_NotMerged_Throws()
+    {
+        if (!GitAvailable) { Assert.True(true, "git not available -- skipping"); return; }
+
+        var (task, _, _) = await SeedWorktreeAsync(TaskStatus.Done);
+        var sut = BuildSut(CreateQueue());
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(
+            () => sut.RevertMerge(task.Id, "main", CancellationToken.None));
+        Assert.Contains("expected Merged", ex.Message);
+    }
+
+    [Fact]
+    public async Task RevertMerge_AfterCleanMerge_RevertsAndReturnsTaskToWaitingForReview()
+    {
+        if (!GitAvailable) { Assert.True(true, "git not available -- skipping"); return; }
+
+        var (task, list, wt) = await SeedWorktreeAsync(TaskStatus.Done);
+        File.WriteAllText(Path.Combine(wt.WorktreePath, "added.txt"), "new\n");
+        GitRepoFixture.RunGit(wt.WorktreePath, "add", "-A");
+        GitRepoFixture.RunGit(wt.WorktreePath, "commit", "-m", "feat: add file");
+
+        var target = await new GitService().GetCurrentBranchAsync(list.WorkingDir!, CancellationToken.None);
+        var sut = BuildSut(CreateQueue());
+        await sut.MergeTask(task.Id, target, true, false, false, cancellationToken: CancellationToken.None);
+        Assert.True(File.Exists(Path.Combine(list.WorkingDir!, "added.txt")));
+
+        var result = await sut.RevertMerge(task.Id, target, CancellationToken.None);
+
+        Assert.True(result.Reverted);
+        Assert.False(string.IsNullOrWhiteSpace(result.RevertCommit));
+        Assert.Empty(result.Conflicts);
+        Assert.False(File.Exists(Path.Combine(list.WorkingDir!, "added.txt")));
+
+        var reloaded = await _tasks.GetByIdAsync(task.Id);
+        Assert.Equal(TaskStatus.WaitingForReview, reloaded!.Status);
+    }
+
+    [Fact]
+    public async Task RevertMerge_ConflictingRevert_ReturnsRevertedFalseWithConflictsAndAbortsCleanly()
+    {
+        if (!GitAvailable) { Assert.True(true, "git not available -- skipping"); return; }
+
+        var (task, list, wt) = await SeedWorktreeAsync(TaskStatus.Done);
+        File.WriteAllText(Path.Combine(wt.WorktreePath, "README.md"), "# test repo\nfeature\n");
+        GitRepoFixture.RunGit(wt.WorktreePath, "add", "-A");
+        GitRepoFixture.RunGit(wt.WorktreePath, "commit", "-m", "feat: append feature line");
+
+        var target = await new GitService().GetCurrentBranchAsync(list.WorkingDir!, CancellationToken.None);
+        var sut = BuildSut(CreateQueue());
+        await sut.MergeTask(task.Id, target, true, false, false, cancellationToken: CancellationToken.None);
+
+        // A later commit on main edits the exact line the merge introduced, so the revert conflicts.
+        File.WriteAllText(Path.Combine(list.WorkingDir!, "README.md"), "# test repo\npost-merge edit\n");
+        GitRepoFixture.RunGit(list.WorkingDir!, "add", "-A");
+        GitRepoFixture.RunGit(list.WorkingDir!, "commit", "-m", "chore: edit the same line");
+        var headBefore = GitRepoFixture.RunGit(list.WorkingDir!, "rev-parse", "HEAD").Trim();
+
+        var result = await sut.RevertMerge(task.Id, target, CancellationToken.None);
+
+        Assert.False(result.Reverted);
+        Assert.Contains("README.md", result.Conflicts);
+        Assert.False(await new GitService().IsMidRevertAsync(list.WorkingDir!));
+        Assert.Equal(headBefore, GitRepoFixture.RunGit(list.WorkingDir!, "rev-parse", "HEAD").Trim());
+
+        var reloaded = await _tasks.GetByIdAsync(task.Id);
+        Assert.Equal(TaskStatus.Done, reloaded!.Status);
+    }
+
    [Fact]
    public async Task ContinueMerge_ParentUnitMergeConflict_RoutesToOrchestratorAndCompletes()
    {