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[flake8-simplify] Fix truthiness assumption for non-iterable arguments in tuple/list/set calls (SIM222, SIM223) #21479

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Merged
ntBre merged 12 commits into from
Dec 1, 2025
Merged

[flake8-simplify] Fix truthiness assumption for non-iterable arguments in tuple/list/set calls (SIM222, SIM223) #21479

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216645d
fix-21473
danparizher Nov 16, 2025
0ee00ed
Update ruff_linter__rules__flake8_pytest_style__tests__PT015.snap
danparizher Nov 16, 2025
2cc5cb7
Update analyze_graph.rs
danparizher Nov 16, 2025
d1987b2
Revert "Update analyze_graph.rs"
danparizher Nov 16, 2025
392858c
Update truthiness checks to include t-strings and f-strings
danparizher Nov 19, 2025
a3d00c1
Explicitly handle various expression types
danparizher Nov 19, 2025
c4041b4
Consolidate logic
danparizher Nov 19, 2025
cc53973
Recurse on string literals
danparizher Nov 28, 2025
ad36495
Update ruff_linter__rules__flake8_pytest_style__tests__PT015.snap
danparizher Nov 28, 2025
7349e9d
remove comment that is redundant with the one below
ntBre Dec 1, 2025
8a5c075
update ok comment, add all covered cases
ntBre Dec 1, 2025
893bcdf
simplify comment slightly
ntBre Dec 1, 2025
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9 changes: 9 additions & 0 deletions crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM222.py
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Expand Up @@ -216,3 +216,12 @@ def get_items_list():

def get_items_set():
return tuple({item for item in items}) or None # OK


# https://github.com/astral-sh/ruff/issues/21473
tuple("") or True # OK
tuple(t"") or True # OK
tuple(0) or True # OK
tuple(1) or True # OK
tuple(False) or True # OK
tuple(None) or True # OK
9 changes: 9 additions & 0 deletions crates/ruff_linter/resources/test/fixtures/flake8_simplify/SIM223.py
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Expand Up @@ -157,3 +157,12 @@

# https://github.com/astral-sh/ruff/issues/7127
def f(a: "'' and 'b'"): ...


# https://github.com/astral-sh/ruff/issues/21473
tuple("") and False # OK
tuple(t"") and False # OK
tuple(0) and False # OK
tuple(1) and False # OK
tuple(False) and False # OK
tuple(None) and False # OK
11 changes: 0 additions & 11 deletions .../flake8_pytest_style/snapshots/ruff_linter__rules__flake8_pytest_style__tests__PT015.snap
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Expand Up @@ -174,14 +174,3 @@ PT015 Assertion always fails, replace with `pytest.fail()`
| ^^^^^^^^^^^^^^^^^
25 | assert tuple("")
|

PT015 Assertion always fails, replace with `pytest.fail()`
--> PT015.py:25:5
|
23 | assert list([])
24 | assert set(set())
25 | assert tuple("")
| ^^^^^^^^^^^^^^^^
26 |
27 | # https://github.com/astral-sh/ruff/issues/19935
|
58 changes: 57 additions & 1 deletion crates/ruff_python_ast/src/helpers.rs
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Expand Up @@ -1329,7 +1329,63 @@ impl Truthiness {
if argument.is_generator_expr() {
Self::Unknown
} else {
Self::from_expr(argument, is_builtin)
// Return Unknown for types with definite truthiness that might result
// in empty iterables or will raise a type error. Explicitly list types
// we recurse for (types without definite truthiness or where Self::from_expr
// correctly handles the truthiness).
match argument {
// Types that raise TypeError when passed to tuple/list/set
Expr::NumberLiteral(_)
| Expr::BooleanLiteral(_)
| Expr::NoneLiteral(_)
| Expr::EllipsisLiteral(_) => {
// For non-iterable arguments like numbers, booleans, None, etc.,
// we can't assume truthiness. For example, tuple(0) raises TypeError.
Self::Unknown
}
// Types with definite truthiness that might result in empty iterables
Expr::StringLiteral(_)
| Expr::TString(_)
| Expr::FString(_)
| Expr::BytesLiteral(_) => {
// For strings/t-strings/f-strings/bytes, tuple("") creates an empty tuple
// which is falsy, but tuple("a") creates a non-empty tuple which
// is truthy. However, we can't assume truthiness matches because
// we conflate truthiness with non-emptiness. For SIM222/SIM223,
// we should be conservative and return Unknown to avoid false positives.
Self::Unknown
}
// Recurse for collections - we need to check if they're empty
Expr::List(_)
| Expr::Set(_)
| Expr::Tuple(_)
| Expr::Dict(_) => Self::from_expr(argument, is_builtin),
// Recurse for comprehensions - they return Unknown in from_expr
Expr::ListComp(_) | Expr::SetComp(_) | Expr::DictComp(_) => {
Self::from_expr(argument, is_builtin)
}
// Recurse for variables and other expressions without definite truthiness
Expr::Name(_)
| Expr::Call(_)
| Expr::Attribute(_)
| Expr::Subscript(_)
| Expr::BinOp(_)
| Expr::UnaryOp(_)
| Expr::If(_)
| Expr::Starred(_)
| Expr::Await(_)
| Expr::Yield(_)
| Expr::YieldFrom(_)
| Expr::Compare(_) => Self::from_expr(argument, is_builtin),
// Return Unknown for types with definite truthiness that don't make sense to recurse
Expr::Lambda(_) | Expr::Generator(_) => {
// Lambda and Generator are always truthy, but when passed to tuple/list/set,
// they might result in empty iterables or raise errors. Return Unknown.
Self::Unknown
}
// Default to Unknown for any other types
_ => Self::Unknown,
}
}
} else {
Self::Unknown
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