Refuse turns, discard and subtasks while a merge is finalizing

internal/agents/mergein.go

@@ -135,6 +135,27 @@ func (m *Manager) recoverMerges(ctx context.Context) error {
 	return nil
 }
 
+func (m *Manager) recoverFinalizing(ctx context.Context) error {
+	finalizing, err := m.store.FinalizingTasks(ctx)
+	if err != nil {
+		return err
+	}
+
+	for _, t := range finalizing {
+		err = m.store.ClearFinalizing(ctx, t.Id)
+		if err != nil {
+			return err
+		}
+		sessions, err := m.store.ListSessions(ctx, t.Id)
+		if err != nil {
+			return err
+		}
+		slog.Error("merge was finishing at startup", "task", t.Id)
+		m.fileTaskError(ctx, t, sessions, "byre restarted while finishing this task's merge, so it may not have been pushed, or the task's worktree may be gone. Check the default branch before merging again.")
+	}
+	return nil
+}
+
 func (m *Manager) startHeldMerges(ctx context.Context) {
 	projects, err := m.store.ProjectsWithQueuedMerges(ctx)
 	if err != nil {
@@ -253,6 +274,10 @@ func (m *Manager) finishMerge(l *live, login string) {
 	}
 
 	slog.Error("finish merge", "task", l.taskID, "err", err)
+	cerr := m.store.ClearFinalizing(ctx, l.taskID)
+	if cerr != nil {
+		slog.Error("clear merge finalizing", "task", l.taskID, "err", cerr)
+	}
 	m.fileError(l, "Merging the task failed: "+err.Error())
 	err = m.Deliver(ctx, l.id)
 	if err != nil {