Move Truthiness into ruff_python_ast (#4071)

crates/ruff/src/checkers/ast/mod.rs

@@ -1615,9 +1615,7 @@ where
                     flake8_bugbear::rules::assert_false(self, stmt, test, msg.as_deref());
                 }
                 if self.settings.rules.enabled(Rule::PytestAssertAlwaysFalse) {
-                    if let Some(diagnostic) = flake8_pytest_style::rules::assert_falsy(stmt, test) {
-                        self.diagnostics.push(diagnostic);
-                    }
+                    flake8_pytest_style::rules::assert_falsy(self, stmt, test);
                 }
                 if self.settings.rules.enabled(Rule::PytestCompositeAssertion) {
                     flake8_pytest_style::rules::composite_condition(

crates/ruff/src/rules/flake8_bandit/rules/shell_injection.rs

@@ -1,12 +1,12 @@
 //! Checks relating to shell injection.
 
-use num_bigint::BigInt;
 use once_cell::sync::Lazy;
 use regex::Regex;
 use rustpython_parser::ast::{Constant, Expr, ExprKind, Keyword};
 
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::helpers::Truthiness;
 use ruff_python_ast::types::Range;
 use ruff_python_semantic::context::Context;
 
@@ -130,74 +130,6 @@ fn get_call_kind(func: &Expr, context: &Context) -> Option<CallKind> {
         })
 }
 
-#[derive(Copy, Clone, Debug)]
-enum Truthiness {
-    // The `shell` keyword argument is set and evaluates to `False`.
-    Falsey,
-    // The `shell` keyword argument is set and evaluates to `True`.
-    Truthy,
-    // The `shell` keyword argument is set, but its value is unknown.
-    Unknown,
-}
-
-impl From<&Keyword> for Truthiness {
-    fn from(value: &Keyword) -> Self {
-        match &value.node.value.node {
-            ExprKind::Constant {
-                value: Constant::Bool(b),
-                ..
-            } => {
-                if *b {
-                    Truthiness::Truthy
-                } else {
-                    Truthiness::Falsey
-                }
-            }
-            ExprKind::Constant {
-                value: Constant::Int(int),
-                ..
-            } => {
-                if int == &BigInt::from(0u8) {
-                    Truthiness::Falsey
-                } else {
-                    Truthiness::Truthy
-                }
-            }
-            ExprKind::Constant {
-                value: Constant::Float(float),
-                ..
-            } => {
-                if (float - 0.0).abs() < f64::EPSILON {
-                    Truthiness::Falsey
-                } else {
-                    Truthiness::Truthy
-                }
-            }
-            ExprKind::Constant {
-                value: Constant::None,
-                ..
-            } => Truthiness::Falsey,
-            ExprKind::List { elts, .. }
-            | ExprKind::Set { elts, .. }
-            | ExprKind::Tuple { elts, .. } => {
-                if elts.is_empty() {
-                    Truthiness::Falsey
-                } else {
-                    Truthiness::Truthy
-                }
-            }
-            ExprKind::Dict { keys, .. } => {
-                if keys.is_empty() {
-                    Truthiness::Falsey
-                } else {
-                    Truthiness::Truthy
-                }
-            }
-            _ => Truthiness::Unknown,
-        }
-    }
-}
-
 #[derive(Copy, Clone, Debug)]
 struct ShellKeyword<'a> {
     /// Whether the `shell` keyword argument is set and evaluates to `True`.
@@ -207,7 +139,7 @@ struct ShellKeyword<'a> {
 }
 
 /// Return the `shell` keyword argument to the given function call, if any.
-fn find_shell_keyword(keywords: &[Keyword]) -> Option<ShellKeyword> {
+fn find_shell_keyword<'a>(ctx: &Context, keywords: &'a [Keyword]) -> Option<ShellKeyword<'a>> {
     keywords
         .iter()
         .find(|keyword| {
@@ -218,7 +150,7 @@ fn find_shell_keyword(keywords: &[Keyword]) -> Option<ShellKeyword> {
                 .map_or(false, |arg| arg == "shell")
         })
         .map(|keyword| ShellKeyword {
-            truthiness: keyword.into(),
+            truthiness: Truthiness::from_expr(&keyword.node.value, |id| ctx.is_builtin(id)),
             keyword,
         })
 }
@@ -255,7 +187,7 @@ pub fn shell_injection(checker: &mut Checker, func: &Expr, args: &[Expr], keywor
 
     if matches!(call_kind, Some(CallKind::Subprocess)) {
         if let Some(arg) = args.first() {
-            match find_shell_keyword(keywords) {
+            match find_shell_keyword(&checker.ctx, keywords) {
                 // S602
                 Some(ShellKeyword {
                     truthiness: Truthiness::Truthy,
@@ -308,7 +240,7 @@ pub fn shell_injection(checker: &mut Checker, func: &Expr, args: &[Expr], keywor
     } else if let Some(ShellKeyword {
         truthiness: Truthiness::Truthy,
         keyword,
-    }) = find_shell_keyword(keywords)
+    }) = find_shell_keyword(&checker.ctx, keywords)
     {
         // S604
         if checker

crates/ruff/src/rules/flake8_pytest_style/rules/assertion.rs

@@ -12,7 +12,7 @@ use rustpython_parser::ast::{
 
 use ruff_diagnostics::{AutofixKind, Diagnostic, Edit, Violation};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::helpers::{has_comments_in, unparse_stmt};
+use ruff_python_ast::helpers::{has_comments_in, unparse_stmt, Truthiness};
 use ruff_python_ast::source_code::{Locator, Stylist};
 use ruff_python_ast::types::Range;
 use ruff_python_ast::visitor::Visitor;
@@ -22,7 +22,6 @@ use crate::checkers::ast::Checker;
 use crate::cst::matchers::match_module;
 use crate::registry::AsRule;
 
-use super::helpers::is_falsy_constant;
 use super::unittest_assert::UnittestAssert;
 
 /// ## What it does
@@ -223,11 +222,11 @@ pub fn unittest_assertion(
 }
 
 /// PT015
-pub fn assert_falsy(stmt: &Stmt, test: &Expr) -> Option<Diagnostic> {
-    if is_falsy_constant(test) {
-        Some(Diagnostic::new(PytestAssertAlwaysFalse, Range::from(stmt)))
-    } else {
-        None
+pub fn assert_falsy(checker: &mut Checker, stmt: &Stmt, test: &Expr) {
+    if Truthiness::from_expr(test, |id| checker.ctx.is_builtin(id)).is_falsey() {
+        checker
+            .diagnostics
+            .push(Diagnostic::new(PytestAssertAlwaysFalse, Range::from(stmt)));
     }
 }
 

crates/ruff/src/rules/flake8_pytest_style/rules/helpers.rs

@@ -1,4 +1,3 @@
-use num_traits::identities::Zero;
 use ruff_python_ast::call_path::{collect_call_path, CallPath};
 use rustpython_parser::ast::{Constant, Expr, ExprKind, Keyword};
 
@@ -6,8 +5,6 @@ use ruff_python_ast::helpers::map_callable;
 
 use crate::checkers::ast::Checker;
 
-const ITERABLE_INITIALIZERS: &[&str] = &["dict", "frozenset", "list", "tuple", "set"];
-
 pub(super) fn get_mark_decorators(decorators: &[Expr]) -> impl Iterator<Item = (&Expr, CallPath)> {
     decorators.iter().filter_map(|decorator| {
         let Some(call_path) = collect_call_path(map_callable(decorator)) else {
@@ -61,48 +58,6 @@ pub(super) fn is_abstractmethod_decorator(decorator: &Expr, checker: &Checker) -
         })
 }
 
-/// Check if the expression is a constant that evaluates to false.
-pub(super) fn is_falsy_constant(expr: &Expr) -> bool {
-    match &expr.node {
-        ExprKind::Constant { value, .. } => match value {
-            Constant::Bool(value) => !*value,
-            Constant::None => true,
-            Constant::Str(string) => string.is_empty(),
-            Constant::Bytes(bytes) => bytes.is_empty(),
-            Constant::Int(int) => int.is_zero(),
-            Constant::Float(float) => *float == 0.0,
-            Constant::Complex { real, imag } => *real == 0.0 && *imag == 0.0,
-            Constant::Ellipsis => true,
-            Constant::Tuple(elts) => elts.is_empty(),
-        },
-        ExprKind::JoinedStr { values, .. } => values.is_empty(),
-        ExprKind::Tuple { elts, .. } | ExprKind::List { elts, .. } => elts.is_empty(),
-        ExprKind::Dict { keys, .. } => keys.is_empty(),
-        ExprKind::Call {
-            func,
-            args,
-            keywords,
-        } => {
-            if let ExprKind::Name { id, .. } = &func.node {
-                if ITERABLE_INITIALIZERS.contains(&id.as_str()) {
-                    if args.is_empty() && keywords.is_empty() {
-                        return true;
-                    } else if !keywords.is_empty() {
-                        return false;
-                    } else if let Some(arg) = args.get(0) {
-                        return is_falsy_constant(arg);
-                    }
-                    return false;
-                }
-                false
-            } else {
-                false
-            }
-        }
-        _ => false,
-    }
-}
-
 pub(super) fn is_pytest_parametrize(decorator: &Expr, checker: &Checker) -> bool {
     checker
         .ctx

crates/ruff_python_ast/src/helpers.rs

@@ -3,6 +3,7 @@ use std::path::Path;
 
 use itertools::Itertools;
 use log::error;
+use num_traits::Zero;
 use once_cell::sync::Lazy;
 use regex::Regex;
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -50,6 +51,13 @@ pub fn unparse_constant(constant: &Constant, stylist: &Stylist) -> String {
     generator.generate()
 }
 
+fn is_iterable_initializer<F>(id: &str, is_builtin: F) -> bool
+where
+    F: Fn(&str) -> bool,
+{
+    matches!(id, "list" | "tuple" | "set" | "dict" | "frozenset") && is_builtin(id)
+}
+
 /// Return `true` if the `Expr` contains an expression that appears to include a
 /// side-effect (like a function call).
 ///
@@ -68,10 +76,7 @@ where
         {
             if args.is_empty() && keywords.is_empty() {
                 if let ExprKind::Name { id, .. } = &func.node {
-                    if !matches!(id.as_str(), "set" | "list" | "tuple" | "dict" | "frozenset") {
-                        return true;
-                    }
-                    if !is_builtin(id) {
+                    if !is_iterable_initializer(id.as_str(), |id| is_builtin(id)) {
                         return true;
                     }
                     return false;
@@ -1422,6 +1427,98 @@ pub fn locate_cmpops(contents: &str) -> Vec<LocatedCmpop> {
     ops
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, is_macro::Is)]
+pub enum Truthiness {
+    // An expression evaluates to `False`.
+    Falsey,
+    // An expression evaluates to `True`.
+    Truthy,
+    // An expression evaluates to an unknown value (e.g., a variable `x` of unknown type).
+    Unknown,
+}
+
+impl From<Option<bool>> for Truthiness {
+    fn from(value: Option<bool>) -> Self {
+        match value {
+            Some(true) => Truthiness::Truthy,
+            Some(false) => Truthiness::Falsey,
+            None => Truthiness::Unknown,
+        }
+    }
+}
+
+impl From<Truthiness> for Option<bool> {
+    fn from(truthiness: Truthiness) -> Self {
+        match truthiness {
+            Truthiness::Truthy => Some(true),
+            Truthiness::Falsey => Some(false),
+            Truthiness::Unknown => None,
+        }
+    }
+}
+
+impl Truthiness {
+    pub fn from_expr<F>(expr: &Expr, is_builtin: F) -> Self
+    where
+        F: Fn(&str) -> bool,
+    {
+        match &expr.node {
+            ExprKind::Constant { value, .. } => match value {
+                Constant::Bool(value) => Some(*value),
+                Constant::None => Some(false),
+                Constant::Str(string) => Some(!string.is_empty()),
+                Constant::Bytes(bytes) => Some(!bytes.is_empty()),
+                Constant::Int(int) => Some(!int.is_zero()),
+                Constant::Float(float) => Some(*float != 0.0),
+                Constant::Complex { real, imag } => Some(*real != 0.0 || *imag != 0.0),
+                Constant::Ellipsis => Some(true),
+                Constant::Tuple(elts) => Some(!elts.is_empty()),
+            },
+            ExprKind::JoinedStr { values, .. } => {
+                if values.is_empty() {
+                    Some(false)
+                } else if values.iter().any(|value| {
+                    let ExprKind::Constant { value: Constant::Str(string), .. } = &value.node else {
+                        return false;
+                    };
+                    !string.is_empty()
+                }) {
+                    Some(true)
+                } else {
+                    None
+                }
+            }
+            ExprKind::List { elts, .. }
+            | ExprKind::Set { elts, .. }
+            | ExprKind::Tuple { elts, .. } => Some(!elts.is_empty()),
+            ExprKind::Dict { keys, .. } => Some(!keys.is_empty()),
+            ExprKind::Call {
+                func,
+                args,
+                keywords,
+            } => {
+                if let ExprKind::Name { id, .. } = &func.node {
+                    if is_iterable_initializer(id.as_str(), |id| is_builtin(id)) {
+                        if args.is_empty() && keywords.is_empty() {
+                            Some(false)
+                        } else if args.len() == 1 && keywords.is_empty() {
+                            Self::from_expr(&args[0], is_builtin).into()
+                        } else {
+                            None
+                        }
+                    } else {
+                        None
+                    }
+                } else {
+                    None
+                }
+            }
+            _ => None,
+        }
+        .into()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use std::borrow::Cow;