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argument-default-in-stub (PYI014)

Derived from the flake8-pyi linter.

Fix is always available.

What it does

Checks for untyped function arguments in stubs with default values that are not "simple" /// (i.e., int, float, complex, bytes, str, bool, None, ..., or simple container literals).

Why is this bad?

Stub (.pyi) files exist to define type hints, and are not evaluated at runtime. As such, function arguments in stub files should not have default values, as they are ignored by type checkers.

However, the use of default values may be useful for IDEs and other consumers of stub files, and so "simple" values may be worth including and are permitted by this rule.

Instead of including and reproducing a complex value, use ... to indicate that the assignment has a default value, but that the value is non-simple or varies according to the current platform or Python version.

Example

def foo(arg=[]) -> None: ...

Use instead:

def foo(arg=...) -> None: ...

References