apache/superset · error · ExtensionNameError

Package name '{name}' cannot start with a number

Error message

Package name '{name}' cannot start with a number

What it means

Part of the Superset extensions CLI scaffolder validation. validate_python_package_name rejects names whose first character is a digit, because Python identifiers (and thus the generated package/module names) cannot start with a number. The rejected name is included in the ExtensionNameError message.

Source

Thrown at superset-extensions-cli/src/superset_extensions_cli/utils.py:195

    return kebab_name.replace("-", "_")


def name_to_kebab_case(name: str) -> str:
    """Convert display name directly to kebab-case (e.g., 'Hello World' -> 'hello-world')."""
    normalized = _normalize_for_identifiers(name)
    return _normalized_to_kebab(normalized)


def validate_python_package_name(name: str) -> None:
    """
    Validate Python package name (snake_case format).

    Raises:
        ExtensionNameError: If name is invalid
    """
    # Check if it starts with a number (invalid for Python identifiers)
    if name[0].isdigit():
        raise ExtensionNameError(f"Package name '{name}' cannot start with a number")

    # Check if the first part (before any underscore) is a Python keyword
    if (first_part := name.split("_")[0]) in PYTHON_KEYWORDS:
        raise ExtensionNameError(
            f"Package name cannot start with Python keyword '{first_part}'"
        )

    # Check if it's a valid Python identifier
    if not name.replace("_", "a").isalnum():
        raise ExtensionNameError(f"'{name}' is not a valid Python package name")


def validate_npm_package_name(name: str) -> None:
    """
    Validate npm package name (kebab-case format).

    Raises:
        ExtensionNameError: If name is invalid

View on GitHub (pinned to f4587218dd)

Solutions

1. Choose a name starting with a letter, e.g. 'view3d' instead of '3dview'.
2. Prefix numeric-leading names with a letter word: 'auth-2fa'.
3. Pre-validate names in any automation that calls the CLI.

Example fix

# before
$ superset-extension new 2fa-auth
# after
$ superset-extension new auth-2fa

def valid_python_package_prefix(name: str) -> bool:
    return bool(name) and not name[0].isdigit()

from superset_extensions_cli.utils import ExtensionNameError

try:
    validate_python_package_name(name)
except ExtensionNameError as e:
    print(f'Pick a different extension name: {e}')
    sys.exit(2)

When it happens

Trigger: Running the extensions CLI new/create command with an extension name like '2fa-auth' or '4xx' whose normalized snake_case package name starts with a digit.

Common situations: Product names that begin with a number ('3d-viewer'); names normalized from camelCase where the leading token is numeric; scripted scaffolding feeding arbitrary strings.

Related errors

• Package name cannot start with Python keyword '{first_part}'
• '{name}' is not a valid Python package name
• '{name}' is a reserved npm package name
• Publisher cannot be empty
• Publisher must start with a letter and contain only lowercas

AI-assisted analysis of apache/superset@f4587218dd (2026-08-14). Data as JSON: /api/errors/96c64b3410d10a51. Report an issue: GitHub.