fullstackhero/dotnet-starter-kit · error · ArgumentOutOfRangeException

Declared size must be positive.

Error message

Declared size must be positive.

What it means

FileAsset.CreatePending validates that declaredSizeBytes > 0 and throws ArgumentOutOfRangeException otherwise. The declared size comes from the client at upload-initiation time and must be a positive number for quota accounting and presigned upload sizing to work.

Solutions

1. Reject empty files on the client before calling CreatePending (if size === 0 show a validation error).
2. Pass the real byte size from File/Blob.size; never default a missing size to 0.
3. If zero-byte uploads must be supported, change the domain rule to allow >= 0 (requires building-block/domain change).
4. Check for int/long coercion issues where a large size overflows negative.

Example fix

// before
await startUpload({ fileName: file.name, contentType: file.type, declaredSizeBytes: file.size ?? 0 });
// after
if (!file || file.size <= 0) { showError('File is empty or unreadable.'); return; }
await startUpload({ fileName: file.name, contentType: file.type, declaredSizeBytes: file.size });

if (!file || !(file instanceof File) || file.size <= 0) {
  showError('File is empty or unreadable.');
  return;
}

const isValidFile = (f: unknown): f is File => f instanceof File && f.size > 0;

When it happens

Trigger: Initiating a file upload where declaredSizeBytes is 0 or negative — e.g. a client computing size of an empty file, a missing/null size defaulting to 0, or a signed/rounding bug producing a negative value.

Common situations: Uploading a zero-byte file (empty blob selected); frontend reading file.size after the File object was invalidated; server-side integrations passing a Content-Length of 0 from a failed download.

Related errors

• Actual size must be positive.
• uploaded size ( ) exceeds declared ( )
• uploaded content-type mismatch
• Group DM requires at least 3 distinct members.
• ChannelId is required.

AI-assisted analysis of fullstackhero/dotnet-starter-kit@3f2959e683 (2026-09-15). Data as JSON: /api/errors/ec598893dbf8eacb. Report an issue: GitHub.

Appendix: source

Thrown at src/Modules/Files/Modules.Files/Domain/FileAsset.cs:61

        Guid? ownerId,
        string originalFileName,
        string sanitizedFileName,
        string contentType,
        long declaredSizeBytes,
        string storageKey,
        Visibility visibility,
        string createdByUserId,
        DateTimeOffset uploadDeadline)
    {
        ArgumentException.ThrowIfNullOrWhiteSpace(ownerType);
        ArgumentException.ThrowIfNullOrWhiteSpace(originalFileName);
        ArgumentException.ThrowIfNullOrWhiteSpace(sanitizedFileName);
        ArgumentException.ThrowIfNullOrWhiteSpace(contentType);
        ArgumentException.ThrowIfNullOrWhiteSpace(storageKey);
        ArgumentException.ThrowIfNullOrWhiteSpace(createdByUserId);
        if (declaredSizeBytes <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(declaredSizeBytes), "Declared size must be positive.");
        }

        return new FileAsset
        {
            Id = id == Guid.Empty ? Guid.CreateVersion7() : id,
            OwnerType = ownerType,
            OwnerId = ownerId,
            OriginalFileName = originalFileName,
            FileName = sanitizedFileName,
            ContentType = contentType,
            SizeBytes = declaredSizeBytes,
            StorageKey = storageKey,
            Visibility = visibility,
            Status = FileAssetStatus.PendingUpload,
            ScanStatus = ScanStatus.NotScanned,
            UploadDeadline = uploadDeadline,
            CreatedByUserId = createdByUserId,
            CreatedAtUtc = DateTime.UtcNow

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