Is there a rule to prefer explicit boolean checks ?

[AbdealiLoKo]

I have a rule in eslint which checks in Typescript when I am using truthy/falsey values - and forces me to provide a better condition.

This encourages people to be more explicit in their condition: val = 0; if(val) should be changed to: val = 0; if(val !== null)

I was wondering if there is something similar in ruff ?

I am one of those people who prefers if val is None: instead of if not val: :)
The closest rule I have seen when I searched around was: https://docs.astral.sh/ruff/rules/compare-to-empty-string/

[hamedrabah]

Ruff does not currently have a direct equivalent of TypeScript ESLint's strict-boolean-expressions rule.

Python deliberately defines truth-value testing for many types, so a blanket rule requiring x is not None, len(x) > 0, and so on would reject a large amount of idiomatic Python. Ruff's boolean-related rules cover narrower problems—for example boolean positional arguments and simplifiable comparisons—but they do not use type information to decide whether if value: is acceptable.

For the specific “optional value accidentally treated as false” class, a type checker is the better enforcement point. Enable strict optional checking in mypy or Pyright and use explicit is None / is not None where zero or an empty container is a valid value. If you need the ESLint policy across all types, it would require a type-aware custom lint rule; Ruff's existing syntax-only rule set cannot reliably distinguish bool, Optional[int], and user-defined truthiness in that expression.