unslothai/unsloth · error · HTTPException

Empty file not allowed

Error message

Empty file not allowed

What it means

HTTP 400 raised by POST /seed/upload-unstructured-file when the uploaded file body is zero bytes (len(content) == 0 after await file.read()). Empty documents cannot be chunked or previewed, so they are rejected up front.

Source

Thrown at studio/backend/routes/data_recipe/seed.py:454

@router.post("/seed/upload-unstructured-file")
async def upload_unstructured_file(
    file: UploadFile = FastAPIFile(...), block_id: str = Form(...)
) -> UnstructuredFileUploadResponse:
    _validate_safe_id(block_id, "block_id")

    original_filename = file.filename or "upload"
    ext = Path(original_filename).suffix.lower()
    if ext not in UNSTRUCTURED_ALLOWED_EXTS:
        raise HTTPException(
            400,
            f"Unsupported file type: {ext}. Allowed: {', '.join(sorted(UNSTRUCTURED_ALLOWED_EXTS))}",
        )

    content = await file.read()
    size_bytes = len(content)

    if size_bytes == 0:
        raise HTTPException(400, "Empty file not allowed")

    if size_bytes > UNSTRUCTURED_RECIPE_UPLOAD_MAX_BYTES:
        raise HTTPException(
            413,
            f"File too large ({size_bytes} bytes). Maximum is {UNSTRUCTURED_RECIPE_UPLOAD_MAX_LABEL}.",
        )

    block_dir = UNSTRUCTURED_UPLOAD_ROOT / block_id
    ensure_dir(block_dir)
    current_total = _get_block_total_size(block_dir)
    if current_total + size_bytes > UNSTRUCTURED_RECIPE_UPLOAD_TOTAL_MAX_BYTES:
        raise HTTPException(
            413,
            f"Total upload limit ({UNSTRUCTURED_RECIPE_UPLOAD_TOTAL_MAX_LABEL}) exceeded",
        )

    file_id = uuid4().hex
    raw_path = block_dir / f"{file_id}{ext}"

View on GitHub (pinned to 203007d190)

Solutions

1. Check file.size > 0 in the picker/submit handler before uploading.
2. If the file should have content, re-download or re-save it and verify in a text editor.
3. Log the filename and size client-side to identify which selection was empty.

Example fix

// before
formData.append('file', selectedFile);

// after
if (selectedFile.size === 0) { alert('File is empty'); return; }
formData.append('file', selectedFile);

if (file.size === 0) { reportError(`${file.name} is empty`); return; }
upload(file);

function isNonEmptyFile(f: File): boolean { return f.size > 0; }

On 400 'Empty file not allowed', skip the file and flag it in the UI; never re-send the same 0-byte body.

When it happens

Trigger: Multipart upload where the file part has a filename but empty body — an empty file picked in a file dialog, a truncated stream, or a programmatically created 0-byte file.

Common situations: User creates a placeholder .txt that was never written to; frontend aborts the read but still submits; upstream download failed silently leaving a 0-byte file that gets forwarded.

Related errors

• Unsupported file type: {ext}. Allowed: {allowed}
• {str(exc)}
• Dropped dataset is empty
• No dataset file was provided
• Empty upload payload

AI-assisted analysis of unslothai/unsloth@203007d190 (2026-08-15). Data as JSON: /api/errors/a5e65162b9fe3f6b. Report an issue: GitHub.