apache/superset · error · DatabaseUploadFailed

Unexpected no file extension found

Error message

Unexpected no file extension found

What it means

DatabaseUploadFailed ('Unexpected no file extension found') raised in ColumnarReader._yield_files when Path(file.filename).suffix is empty. The Columnar reader dispatches on the file extension (zip vs single Parquet), so a file with no extension cannot be routed and the upload is rejected before any parsing.

Source

Thrown at superset/commands/database/uploaders/columnar_reader.py:87

        ) as ex:
            raise DatabaseUploadFailed(
                message=_("Parsing error: %(error)s", error=str(ex))
            ) from ex
        except Exception as ex:
            raise DatabaseUploadFailed(_("Error reading Columnar file")) from ex

    @staticmethod
    def _yield_files(file: FileStorage) -> Generator[IO[bytes], None, None]:
        """
        Yields files from the provided file. If the file is a zip file, it yields each
        file within the zip file. If it's a single file, it yields the file itself.

        :param file: The file to yield files from.
        :return: A generator that yields files.
        """
        file_suffix = Path(file.filename).suffix
        if not file_suffix:
            raise DatabaseUploadFailed(_("Unexpected no file extension found"))
        file_suffix = file_suffix[1:]  # remove the dot
        if file_suffix == "zip":
            if not is_zipfile(file):
                raise DatabaseUploadFailed(_("Not a valid ZIP file"))
            try:
                with ZipFile(file) as zip_file:
                    # guard against decompression bombs before reading entries,
                    # mirroring the importer path
                    try:
                        check_is_safe_zip(zip_file)
                    except SupersetException as ex:
                        raise DatabaseUploadFailed(str(ex)) from ex
                    # check if all file types are of the same extension
                    file_suffixes = {Path(name).suffix for name in zip_file.namelist()}
                    if len(file_suffixes) > 1:
                        raise DatabaseUploadFailed(
                            _("ZIP file contains multiple file types")
                        )

View on GitHub (pinned to f4587218dd)

Solutions

1. Rename the file to include the correct extension, e.g. data.parquet (or data.zip for archives)
2. If uploading programmatically, set the multipart filename explicitly: files={'file': ('data.parquet', fh, 'application/octet-stream')}
3. Validate the extension client-side before starting the upload

Example fix

# before
curl -F 'file=@/tmp/tmp8123' ...
# after
curl -F 'file=@/tmp/tmp8123;filename=data.parquet' ...

from pathlib import Path

def has_extension(filename: str | None) -> bool:
    return bool(filename and Path(filename).suffix)

When it happens

Trigger: Uploading a file whose Flask FileStorage filename has no dot-separated suffix, e.g. 'data', 'output', or a client that sends filename without extension; also filenames ending in a dot ('data.') yield an empty suffix.

Common situations: Programmatic API uploads (POST to /api/v1/database/<id>/upload/ with form-data) where the filename field is omitted or set to a bare name; temp files renamed without extension; some browsers/SDKs defaulting to blob filenames.

Related errors

• Parsing error: %(error)s
• Error reading Columnar file
• Not a valid ZIP file
• ZIP file contains multiple file types
• Unsupported whisker type: ${whiskerOptions}

AI-assisted analysis of apache/superset@f4587218dd (2026-08-14). Data as JSON: /api/errors/d59f3ef65d7ef622. Report an issue: GitHub.