Improve ruff_python_semantic::all::extract_all_names() (#11335)

crates/ruff_python_semantic/src/model/all.rs

@@ -0,0 +1,205 @@
+//! Utilities for semantic analysis of `__all__` definitions
+
+use bitflags::bitflags;
+
+use ruff_python_ast::{self as ast, helpers::map_subscript, Expr, Stmt};
+use ruff_text_size::{Ranged, TextRange};
+
+use crate::SemanticModel;
+
+bitflags! {
+    #[derive(Default, Debug, Copy, Clone, PartialEq, Eq)]
+    pub struct DunderAllFlags: u8 {
+        /// The right-hand-side assignment to __all__ uses an invalid expression (i.e., an
+        /// expression that doesn't evaluate to a container type, like `__all__ = 1`).
+        const INVALID_FORMAT = 1 << 0;
+        /// The right-hand-side assignment to __all__ contains an invalid member (i.e., a
+        /// non-string, like `__all__ = [1]`).
+        const INVALID_OBJECT = 1 << 1;
+    }
+}
+
+/// Abstraction for a string inside an `__all__` definition,
+/// e.g. `"foo"` in `__all__ = ["foo"]`
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct DunderAllName<'a> {
+    /// The value of the string inside the `__all__` definition
+    name: &'a str,
+
+    /// The range of the string inside the `__all__` definition
+    range: TextRange,
+}
+
+impl DunderAllName<'_> {
+    pub fn name(&self) -> &str {
+        self.name
+    }
+}
+
+impl Ranged for DunderAllName<'_> {
+    fn range(&self) -> TextRange {
+        self.range
+    }
+}
+
+/// Abstraction for a collection of names inside an `__all__` definition,
+/// e.g. `["foo", "bar"]` in `__all__ = ["foo", "bar"]`
+#[derive(Debug, Clone)]
+pub struct DunderAllDefinition<'a> {
+    /// The range of the `__all__` identifier.
+    range: TextRange,
+    /// The names inside the `__all__` definition.
+    names: Vec<DunderAllName<'a>>,
+}
+
+impl<'a> DunderAllDefinition<'a> {
+    /// Initialize a new [`DunderAllDefinition`] instance.
+    pub fn new(range: TextRange, names: Vec<DunderAllName<'a>>) -> Self {
+        Self { range, names }
+    }
+
+    /// The names inside the `__all__` definition.
+    pub fn names(&self) -> &[DunderAllName<'a>] {
+        &self.names
+    }
+}
+
+impl Ranged for DunderAllDefinition<'_> {
+    fn range(&self) -> TextRange {
+        self.range
+    }
+}
+
+impl<'a> SemanticModel<'a> {
+    /// Extract the names bound to a given __all__ assignment.
+    pub fn extract_dunder_all_names<'expr>(
+        &self,
+        stmt: &'expr Stmt,
+    ) -> (Vec<DunderAllName<'expr>>, DunderAllFlags) {
+        fn add_to_names<'expr>(
+            elts: &'expr [Expr],
+            names: &mut Vec<DunderAllName<'expr>>,
+            flags: &mut DunderAllFlags,
+        ) {
+            for elt in elts {
+                if let Expr::StringLiteral(ast::ExprStringLiteral { value, range }) = elt {
+                    names.push(DunderAllName {
+                        name: value.to_str(),
+                        range: *range,
+                    });
+                } else {
+                    *flags |= DunderAllFlags::INVALID_OBJECT;
+                }
+            }
+        }
+
+        let mut names: Vec<DunderAllName> = vec![];
+        let mut flags = DunderAllFlags::empty();
+
+        if let Some(value) = match stmt {
+            Stmt::Assign(ast::StmtAssign { value, .. }) => Some(value),
+            Stmt::AnnAssign(ast::StmtAnnAssign { value, .. }) => value.as_ref(),
+            Stmt::AugAssign(ast::StmtAugAssign { value, .. }) => Some(value),
+            _ => None,
+        } {
+            if let Expr::BinOp(ast::ExprBinOp { left, right, .. }) = value.as_ref() {
+                let mut current_left = left;
+                let mut current_right = right;
+                loop {
+                    // Process the right side, which should be a "real" value.
+                    let (elts, new_flags) = self.extract_dunder_all_elts(current_right);
+                    flags |= new_flags;
+                    if let Some(elts) = elts {
+                        add_to_names(elts, &mut names, &mut flags);
+                    }
+
+                    // Process the left side, which can be a "real" value or the "rest" of the
+                    // binary operation.
+                    if let Expr::BinOp(ast::ExprBinOp { left, right, .. }) = current_left.as_ref() {
+                        current_left = left;
+                        current_right = right;
+                    } else {
+                        let (elts, new_flags) = self.extract_dunder_all_elts(current_left);
+                        flags |= new_flags;
+                        if let Some(elts) = elts {
+                            add_to_names(elts, &mut names, &mut flags);
+                        }
+                        break;
+                    }
+                }
+            } else {
+                let (elts, new_flags) = self.extract_dunder_all_elts(value);
+                flags |= new_flags;
+                if let Some(elts) = elts {
+                    add_to_names(elts, &mut names, &mut flags);
+                }
+            }
+        }
+
+        (names, flags)
+    }
+
+    fn extract_dunder_all_elts<'expr>(
+        &self,
+        expr: &'expr Expr,
+    ) -> (Option<&'expr [Expr]>, DunderAllFlags) {
+        match expr {
+            Expr::List(ast::ExprList { elts, .. }) => {
+                return (Some(elts), DunderAllFlags::empty());
+            }
+            Expr::Tuple(ast::ExprTuple { elts, .. }) => {
+                return (Some(elts), DunderAllFlags::empty());
+            }
+            Expr::ListComp(_) => {
+                // Allow comprehensions, even though we can't statically analyze them.
+                return (None, DunderAllFlags::empty());
+            }
+            Expr::Name(ast::ExprName { id, .. }) => {
+                // Ex) `__all__ = __all__ + multiprocessing.__all__`
+                if id == "__all__" {
+                    return (None, DunderAllFlags::empty());
+                }
+            }
+            Expr::Attribute(ast::ExprAttribute { attr, .. }) => {
+                // Ex) `__all__ = __all__ + multiprocessing.__all__`
+                if attr == "__all__" {
+                    return (None, DunderAllFlags::empty());
+                }
+            }
+            Expr::Call(ast::ExprCall {
+                func, arguments, ..
+            }) => {
+                // Allow `tuple()`, `list()`, and their generic forms, like `list[int]()`.
+                if arguments.keywords.is_empty() && arguments.args.len() <= 1 {
+                    if self
+                        .resolve_builtin_symbol(map_subscript(func))
+                        .is_some_and(|symbol| matches!(symbol, "tuple" | "list"))
+                    {
+                        let [arg] = arguments.args.as_ref() else {
+                            return (None, DunderAllFlags::empty());
+                        };
+                        match arg {
+                            Expr::List(ast::ExprList { elts, .. })
+                            | Expr::Set(ast::ExprSet { elts, .. })
+                            | Expr::Tuple(ast::ExprTuple { elts, .. }) => {
+                                return (Some(elts), DunderAllFlags::empty());
+                            }
+                            _ => {
+                                // We can't analyze other expressions, but they must be
+                                // valid, since the `list` or `tuple` call will ultimately
+                                // evaluate to a list or tuple.
+                                return (None, DunderAllFlags::empty());
+                            }
+                        }
+                    }
+                }
+            }
+            Expr::Named(ast::ExprNamed { value, .. }) => {
+                // Allow, e.g., `__all__ += (value := ["A", "B"])`.
+                return self.extract_dunder_all_elts(value);
+            }
+            _ => {}
+        }
+        (None, DunderAllFlags::INVALID_FORMAT)
+    }
+}