apache/superset · error · IncorrectVersionError

{file_name} is not a valid YAML file

Error message

{file_name} is not a valid YAML file

What it means

IncorrectVersionError ('{file_name} is not a valid YAML file') is raised by the v0 importer's validate() when yaml.safe_load(content) raises a yaml.YAMLError — the file's content is syntactically invalid YAML (bad indentation, stray tabs, unclosed quotes/brackets). It is raised as IncorrectVersionError so the dispatcher treats it as 'file not handled' and moves on, ultimately surfacing as the 'Could not find a valid command to import file' error if no importer accepts any file.

Source

Thrown at superset/commands/dataset/importers/v0.py:303

                    # UI exports don't have the database metadata, so we assume
                    # the DB exists and has the same name
                    params = json.loads(dataset["params"])
                    database = (
                        db.session.query(Database)
                        .filter_by(database_name=params["database_name"])
                        .one()
                    )
                    dataset["database_id"] = database.id
                    SqlaTable.import_from_dict(dataset, sync=self.sync)

    def validate(self) -> None:
        # ensure all files are YAML
        for file_name, content in self.contents.items():
            try:
                config = yaml.safe_load(content)
            except yaml.YAMLError as ex:
                logger.exception("Invalid YAML file")
                raise IncorrectVersionError(
                    f"{file_name} is not a valid YAML file"
                ) from ex

            # CLI export
            if isinstance(config, dict):
                # TODO (betodealmeida): validate with Marshmallow
                if DATABASES_KEY not in config:
                    raise IncorrectVersionError(f"{file_name} has no valid keys")

            # UI export
            elif isinstance(config, list):
                # TODO (betodealmeida): validate with Marshmallow
                pass

            else:
                raise IncorrectVersionError(f"{file_name} is not a valid file")

            self._configs[file_name] = config

View on GitHub (pinned to f4587218dd)

Solutions

1. Open the named file and run it through a YAML linter or `python -c "import yaml,sys; yaml.safe_load(open(sys.argv[1]))" file.yaml` to get the exact line/column of the syntax error.
2. Replace tabs with spaces and fix indentation/quote issues at the reported position.
3. Prefer regenerating the export from the source instance rather than hand-repairing.

Example fix

# before (tab indentation -> yaml.YAMLError)
- table_name: sales
	columns:
		- column_name: id

# after (spaces only)
- table_name: sales
  columns:
    - column_name: id

# Lint every file for YAML validity before upload
import yaml

def invalid_yaml_files(contents: dict) -> list[str]:
    bad = []
    for name, text in contents.items():
        try:
            yaml.safe_load(text)
        except yaml.YAMLError:
            bad.append(name)
    return bad  # non-empty -> fix these files before calling the importer

from superset.commands.exceptions import IncorrectVersionError
bad = invalid_yaml_files(contents)
if bad:
    reject_upload(bad)  # client-side: name the files, never call the API
else:
    ImportDatasetsCommand(contents, {})

When it happens

Trigger: Importing a bundle containing a malformed YAML file: tabs used for indentation, a value with an unescaped colon, truncated download/copy-paste, or a binary/JSON file misnamed .yaml. The error message names the offending file_name.

Common situations: Hand-editing exported YAML and breaking indentation; files edited with editors inserting tabs; partial uploads; converting exports through scripts that mangle quoting.

Related errors

• Not a ZIP file
• No valid import files were found
• Could not find a valid command to import file
• Could not find a valid command to import file
• User doesn't have permission to create or update databases

AI-assisted analysis of apache/superset@f4587218dd (2026-08-14). Data as JSON: /api/errors/93c650497e3a08d2. Report an issue: GitHub.