fullstackhero/dotnet-starter-kit · error · NotFoundException

Parent message not found.

Error message

Parent message not found.

What it means

The parent message lookup by query.ParentMessageId found no row, so the handler throws NotFoundException('Parent message not found.') (HTTP 404). Thrown at the parent query itself when the message id simply doesn't exist (or is invisible due to tenant filtering).

Solutions

1. Verify the parent message id exists in the current tenant before querying replies
2. Refresh thread state on the client; handle 404 by removing the stale parent from the UI
3. Confirm tenant resolution matches the message's tenant
4. Check DB for soft-deleted message rows if the id should exist

if (!parentMessageId) throw new Error('parentMessageId is required');
if (!messages.some(m => m.id === parentMessageId)) throw new Error('parent message not loaded');

function hasParent(m: Message | undefined): m is Message { return m !== undefined && !m.deleted; }

try { return await listMessageReplies(parentId); }
catch (e) { if (isNotFound(e)) { removeThreadFromUi(parentId); return []; } throw e; }

When it happens

Trigger: Listing replies for a ParentMessageId that does not exist, was hard/soft deleted, or belongs to another tenant.

Common situations: Client holds a reply-to id from a deleted message, cross-tenant id, or stale UI state pointing at a purged thread.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• Message not found.
• Message not found.
• Message not found.
• User is not a member.
• Channel not found.

AI-assisted analysis of fullstackhero/dotnet-starter-kit@3f2959e683 (2026-09-15). Data as JSON: /api/errors/9587ef9ada292bd4. Report an issue: GitHub.

Appendix: source

Thrown at src/Modules/Chat/Modules.Chat/Features/v1/Messages/ListMessageReplies/ListMessageRepliesQueryHandler.cs:34

    IMediator mediator)
    : IQueryHandler<ListMessageRepliesQuery, ReadOnlyCollection<MessageDto>>
{
    public async ValueTask<ReadOnlyCollection<MessageDto>> Handle(
        ListMessageRepliesQuery query,
        CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(query);
        var userId = currentUser.GetUserId();
        if (userId == Guid.Empty) throw new UnauthorizedException("no current user");
        var currentUserId = userId.ToString();

        // Load the parent so we can authorize the caller through the channel.
        var parent = await db.Messages
            .Where(m => m.Id == query.ParentMessageId)
            .Select(m => new { m.Id, m.ChannelId })
            .FirstOrDefaultAsync(cancellationToken)
            .ConfigureAwait(false)
            ?? throw new NotFoundException("Parent message not found.");

        var channel = await db.Channels.FirstOrDefaultAsync(c => c.Id == parent.ChannelId, cancellationToken)
            .ConfigureAwait(false)
            ?? throw new NotFoundException("Parent message not found.");
        channel.RequireMember(currentUserId);

        IQueryable<Domain.Message> q = db.Messages
            .Where(m => m.ParentMessageId == query.ParentMessageId);

        if (query.Before is { } beforeId)
        {
            q = q.Where(m => m.Id.CompareTo(beforeId) < 0);
        }

        var rows = await q
            .OrderByDescending(m => m.Id)
            .Take(query.PageSize)
            .Include(m => m.Attachments)

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