duplicate-entry-in-dunder-all (RUF068)

Preview (since 0.14.14) · Related issues · View source

Fix is sometimes available.

This rule is unstable and in preview. The --preview flag is required for use.

What it does

Detects duplicate elements in __all__ definitions.

Why is this bad?

Duplicate elements in __all__ serve no purpose and can indicate copy-paste errors or incomplete refactoring.

Example

__all__ = [
    "DatabaseConnection",
    "Product",
    "User",
    "DatabaseConnection",  # Duplicate
]

Use instead:

__all__ = [
    "DatabaseConnection",
    "Product",
    "User",
]

Fix Safety

This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression, potentially losing important context or documentation.

For example:

__all__ = [
    "PublicAPI",
    # TODO: Remove this in v2.0
    "PublicAPI",  # Deprecated alias
]