unnecessary-cast-to-int (RUF046)

Fix is always available.

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

What it does

Checks for int conversions of values that are already integers.

Why is this bad?

Such a conversion is unnecessary.

Known problems

This rule may produce false positives for round, math.ceil, math.floor, and math.trunc calls when values override the __round__, __ceil__, __floor__, or __trunc__ operators such that they don't return an integer.

Example

int(len([]))
int(round(foo, None))

Use instead:

len([])
round(foo)

Fix safety

The fix for round, math.ceil, math.floor, and math.truncate is unsafe because removing the int conversion can change the semantics for values overriding the __round__, __ceil__, __floor__, or __trunc__ dunder methods such that they don't return an integer.