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unused-async (RUF029)#

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

What it does#

Checks for functions declared async that do not await or otherwise use features requiring the function to be declared async.

Why is this bad?#

Declaring a function async when it's not is usually a mistake, and will artificially limit the contexts where that function may be called. In some cases, labeling a function async is semantically meaningful (e.g. with the trio library).


async def foo():

Use instead:

def foo():