ruff/crates/ruff_python_semantic/src/analyze/typing.rs

1004 lines
35 KiB
Rust

//! Analysis rules for the `typing` module.
use ruff_python_ast::helpers::{any_over_expr, is_const_false, map_subscript};
use ruff_python_ast::name::QualifiedName;
use ruff_python_ast::{self as ast, Expr, Int, Operator, ParameterWithDefault, Parameters, Stmt};
use ruff_python_stdlib::typing::{
as_pep_585_generic, has_pep_585_generic, is_immutable_generic_type,
is_immutable_non_generic_type, is_immutable_return_type, is_literal_member,
is_mutable_return_type, is_pep_593_generic_member, is_pep_593_generic_type,
is_standard_library_generic, is_standard_library_generic_member, is_standard_library_literal,
};
use ruff_text_size::Ranged;
use crate::analyze::type_inference::{NumberLike, PythonType, ResolvedPythonType};
use crate::model::SemanticModel;
use crate::{Binding, BindingKind, Modules};
#[derive(Debug, Copy, Clone)]
pub enum Callable {
Bool,
Cast,
NewType,
TypeVar,
NamedTuple,
TypedDict,
MypyExtension,
}
#[derive(Debug, Copy, Clone)]
pub enum SubscriptKind {
/// A subscript of the form `typing.Literal["foo", "bar"]`, i.e., a literal.
Literal,
/// A subscript of the form `typing.List[int]`, i.e., a generic.
Generic,
/// A subscript of the form `typing.Annotated[int, "foo"]`, i.e., a PEP 593 annotation.
PEP593Annotation,
}
pub fn match_annotated_subscript<'a>(
expr: &Expr,
semantic: &SemanticModel,
typing_modules: impl Iterator<Item = &'a str>,
extend_generics: &[String],
) -> Option<SubscriptKind> {
semantic
.resolve_qualified_name(expr)
.and_then(|qualified_name| {
if is_standard_library_literal(qualified_name.segments()) {
return Some(SubscriptKind::Literal);
}
if is_standard_library_generic(qualified_name.segments())
|| extend_generics
.iter()
.map(|target| QualifiedName::from_dotted_name(target))
.any(|target| qualified_name == target)
{
return Some(SubscriptKind::Generic);
}
if is_pep_593_generic_type(qualified_name.segments()) {
return Some(SubscriptKind::PEP593Annotation);
}
for module in typing_modules {
let module_qualified_name = QualifiedName::user_defined(module);
if qualified_name.starts_with(&module_qualified_name) {
if let Some(member) = qualified_name.segments().last() {
if is_literal_member(member) {
return Some(SubscriptKind::Literal);
}
if is_standard_library_generic_member(member) {
return Some(SubscriptKind::Generic);
}
if is_pep_593_generic_member(member) {
return Some(SubscriptKind::PEP593Annotation);
}
}
}
}
None
})
}
#[derive(Debug, Clone, Eq, PartialEq)]
pub enum ModuleMember {
/// A builtin symbol, like `"list"`.
BuiltIn(&'static str),
/// A module member, like `("collections", "deque")`.
Member(&'static str, &'static str),
}
impl std::fmt::Display for ModuleMember {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
ModuleMember::BuiltIn(name) => std::write!(f, "{name}"),
ModuleMember::Member(module, member) => std::write!(f, "{module}.{member}"),
}
}
}
/// Returns the PEP 585 standard library generic variant for a `typing` module reference, if such
/// a variant exists.
pub fn to_pep585_generic(expr: &Expr, semantic: &SemanticModel) -> Option<ModuleMember> {
semantic
.seen_module(Modules::TYPING | Modules::TYPING_EXTENSIONS)
.then(|| semantic.resolve_qualified_name(expr))
.flatten()
.and_then(|qualified_name| {
let [module, member] = qualified_name.segments() else {
return None;
};
as_pep_585_generic(module, member).map(|(module, member)| {
if module.is_empty() {
ModuleMember::BuiltIn(member)
} else {
ModuleMember::Member(module, member)
}
})
})
}
/// Return whether a given expression uses a PEP 585 standard library generic.
pub fn is_pep585_generic(expr: &Expr, semantic: &SemanticModel) -> bool {
semantic
.resolve_qualified_name(expr)
.is_some_and(|qualified_name| {
let [module, name] = qualified_name.segments() else {
return false;
};
has_pep_585_generic(module, name)
})
}
#[derive(Debug, Copy, Clone)]
pub enum Pep604Operator {
/// The union operator, e.g., `Union[str, int]`, expressible as `str | int` after PEP 604.
Union,
/// The union operator, e.g., `Optional[str]`, expressible as `str | None` after PEP 604.
Optional,
}
/// Return the PEP 604 operator variant to which the given subscript [`Expr`] corresponds, if any.
pub fn to_pep604_operator(
value: &Expr,
slice: &Expr,
semantic: &SemanticModel,
) -> Option<Pep604Operator> {
/// Returns `true` if any argument in the slice is a quoted annotation.
fn quoted_annotation(slice: &Expr) -> bool {
match slice {
Expr::StringLiteral(_) => true,
Expr::Tuple(tuple) => tuple.iter().any(quoted_annotation),
_ => false,
}
}
/// Returns `true` if any argument in the slice is a starred expression.
fn starred_annotation(slice: &Expr) -> bool {
match slice {
Expr::Starred(_) => true,
Expr::Tuple(tuple) => tuple.iter().any(starred_annotation),
_ => false,
}
}
// If the typing modules were never imported, we'll never match below.
if !semantic.seen_typing() {
return None;
}
// If the slice is a forward reference (e.g., `Optional["Foo"]`), it can only be rewritten
// if we're in a typing-only context.
//
// This, for example, is invalid, as Python will evaluate `"Foo" | None` at runtime in order to
// populate the function's `__annotations__`:
// ```python
// def f(x: "Foo" | None): ...
// ```
//
// This, however, is valid:
// ```python
// def f():
// x: "Foo" | None
// ```
if quoted_annotation(slice) {
if semantic.execution_context().is_runtime() {
return None;
}
}
// If any of the elements are starred expressions, we can't rewrite the subscript:
// ```python
// def f(x: Union[*int, str]): ...
// ```
if starred_annotation(slice) {
return None;
}
semantic
.resolve_qualified_name(value)
.as_ref()
.and_then(|qualified_name| {
if semantic.match_typing_qualified_name(qualified_name, "Optional") {
Some(Pep604Operator::Optional)
} else if semantic.match_typing_qualified_name(qualified_name, "Union") {
Some(Pep604Operator::Union)
} else {
None
}
})
}
/// Return `true` if `Expr` represents a reference to a type annotation that resolves to an
/// immutable type.
pub fn is_immutable_annotation(
expr: &Expr,
semantic: &SemanticModel,
extend_immutable_calls: &[QualifiedName],
) -> bool {
match expr {
Expr::Name(_) | Expr::Attribute(_) => {
semantic
.resolve_qualified_name(expr)
.is_some_and(|qualified_name| {
is_immutable_non_generic_type(qualified_name.segments())
|| is_immutable_generic_type(qualified_name.segments())
|| extend_immutable_calls
.iter()
.any(|target| qualified_name == *target)
})
}
Expr::Subscript(ast::ExprSubscript { value, slice, .. }) => semantic
.resolve_qualified_name(value)
.is_some_and(|qualified_name| {
if is_immutable_generic_type(qualified_name.segments()) {
true
} else if matches!(qualified_name.segments(), ["typing", "Union"]) {
if let Expr::Tuple(tuple) = &**slice {
tuple.iter().all(|element| {
is_immutable_annotation(element, semantic, extend_immutable_calls)
})
} else {
false
}
} else if matches!(qualified_name.segments(), ["typing", "Optional"]) {
is_immutable_annotation(slice, semantic, extend_immutable_calls)
} else if is_pep_593_generic_type(qualified_name.segments()) {
if let Expr::Tuple(ast::ExprTuple { elts, .. }) = slice.as_ref() {
elts.first().is_some_and(|elt| {
is_immutable_annotation(elt, semantic, extend_immutable_calls)
})
} else {
false
}
} else {
false
}
}),
Expr::BinOp(ast::ExprBinOp {
left,
op: Operator::BitOr,
right,
range: _,
}) => {
is_immutable_annotation(left, semantic, extend_immutable_calls)
&& is_immutable_annotation(right, semantic, extend_immutable_calls)
}
Expr::NoneLiteral(_) => true,
_ => false,
}
}
/// Return `true` if `func` is a function that returns an immutable value.
pub fn is_immutable_func(
func: &Expr,
semantic: &SemanticModel,
extend_immutable_calls: &[QualifiedName],
) -> bool {
semantic
.resolve_qualified_name(map_subscript(func))
.is_some_and(|qualified_name| {
is_immutable_return_type(qualified_name.segments())
|| extend_immutable_calls
.iter()
.any(|target| qualified_name == *target)
})
}
/// Return `true` if `func` is a function that returns a mutable value.
pub fn is_mutable_func(func: &Expr, semantic: &SemanticModel) -> bool {
semantic
.resolve_qualified_name(func)
.as_ref()
.map(QualifiedName::segments)
.is_some_and(is_mutable_return_type)
}
/// Return `true` if `expr` is an expression that resolves to a mutable value.
pub fn is_mutable_expr(expr: &Expr, semantic: &SemanticModel) -> bool {
match expr {
Expr::List(_)
| Expr::Dict(_)
| Expr::Set(_)
| Expr::ListComp(_)
| Expr::DictComp(_)
| Expr::SetComp(_) => true,
Expr::Call(ast::ExprCall { func, .. }) => is_mutable_func(map_subscript(func), semantic),
_ => false,
}
}
/// Return `true` if [`ast::StmtIf`] is a guard for a type-checking block.
pub fn is_type_checking_block(stmt: &ast::StmtIf, semantic: &SemanticModel) -> bool {
let ast::StmtIf { test, .. } = stmt;
// Ex) `if False:`
if is_const_false(test) {
return true;
}
// Ex) `if 0:`
if matches!(
test.as_ref(),
Expr::NumberLiteral(ast::ExprNumberLiteral {
value: ast::Number::Int(Int::ZERO),
..
})
) {
return true;
}
// Ex) `if typing.TYPE_CHECKING:`
if semantic.match_typing_expr(test, "TYPE_CHECKING") {
return true;
}
false
}
/// Returns `true` if the [`ast::StmtIf`] is a version-checking block (e.g., `if sys.version_info >= ...:`).
pub fn is_sys_version_block(stmt: &ast::StmtIf, semantic: &SemanticModel) -> bool {
let ast::StmtIf { test, .. } = stmt;
any_over_expr(test, &|expr| {
semantic
.resolve_qualified_name(expr)
.is_some_and(|qualified_name| {
matches!(
qualified_name.segments(),
["sys", "version_info" | "platform"]
)
})
})
}
/// Traverse a "union" type annotation, applying `func` to each union member.
///
/// Supports traversal of `Union` and `|` union expressions.
///
/// The function is called with each expression in the union (excluding declarations of nested
/// unions) and the parent expression.
pub fn traverse_union<'a, F>(func: &mut F, semantic: &SemanticModel, expr: &'a Expr)
where
F: FnMut(&'a Expr, &'a Expr),
{
fn inner<'a, F>(
func: &mut F,
semantic: &SemanticModel,
expr: &'a Expr,
parent: Option<&'a Expr>,
) where
F: FnMut(&'a Expr, &'a Expr),
{
// Ex) `x | y`
if let Expr::BinOp(ast::ExprBinOp {
op: Operator::BitOr,
left,
right,
range: _,
}) = expr
{
// The union data structure usually looks like this:
// a | b | c -> (a | b) | c
//
// However, parenthesized expressions can coerce it into any structure:
// a | (b | c)
//
// So we have to traverse both branches in order (left, then right), to report members
// in the order they appear in the source code.
// Traverse the left then right arms
inner(func, semantic, left, Some(expr));
inner(func, semantic, right, Some(expr));
return;
}
// Ex) `Union[x, y]`
if let Expr::Subscript(ast::ExprSubscript { value, slice, .. }) = expr {
if semantic.match_typing_expr(value, "Union") {
if let Expr::Tuple(tuple) = &**slice {
// Traverse each element of the tuple within the union recursively to handle cases
// such as `Union[..., Union[...]]`
tuple
.iter()
.for_each(|elem| inner(func, semantic, elem, Some(expr)));
return;
}
// Ex) `Union[Union[a, b]]` and `Union[a | b | c]`
inner(func, semantic, slice, Some(expr));
return;
}
}
// Otherwise, call the function on expression, if it's not the top-level expression.
if let Some(parent) = parent {
func(expr, parent);
}
}
inner(func, semantic, expr, None);
}
/// Traverse a "literal" type annotation, applying `func` to each literal member.
///
/// The function is called with each expression in the literal (excluding declarations of nested
/// literals) and the parent expression.
pub fn traverse_literal<'a, F>(func: &mut F, semantic: &SemanticModel, expr: &'a Expr)
where
F: FnMut(&'a Expr, &'a Expr),
{
fn inner<'a, F>(
func: &mut F,
semantic: &SemanticModel,
expr: &'a Expr,
parent: Option<&'a Expr>,
) where
F: FnMut(&'a Expr, &'a Expr),
{
// Ex) `Literal[x, y]`
if let Expr::Subscript(ast::ExprSubscript { value, slice, .. }) = expr {
if semantic.match_typing_expr(value, "Literal") {
match &**slice {
Expr::Tuple(tuple) => {
// Traverse each element of the tuple within the literal recursively to handle cases
// such as `Literal[..., Literal[...]]`
for element in tuple {
inner(func, semantic, element, Some(expr));
}
}
other => {
// Ex) `Literal[Literal[...]]`
inner(func, semantic, other, Some(expr));
}
}
}
} else {
// Otherwise, call the function on expression, if it's not the top-level expression.
if let Some(parent) = parent {
func(expr, parent);
}
}
}
inner(func, semantic, expr, None);
}
/// Abstraction for a type checker, conservatively checks for the intended type(s).
pub trait TypeChecker {
/// Check annotation expression to match the intended type(s).
fn match_annotation(annotation: &Expr, semantic: &SemanticModel) -> bool;
/// Check initializer expression to match the intended type(s).
fn match_initializer(initializer: &Expr, semantic: &SemanticModel) -> bool;
}
/// Check if the type checker accepts the given binding with the given name.
///
/// NOTE: this function doesn't perform more serious type inference, so it won't be able
/// to understand if the value gets initialized from a call to a function always returning
/// lists. This also implies no interfile analysis.
fn check_type<T: TypeChecker>(binding: &Binding, semantic: &SemanticModel) -> bool {
match binding.kind {
BindingKind::Assignment => match binding.statement(semantic) {
// Given:
//
// ```python
// x = init_expr
// ```
//
// The type checker might know how to infer the type based on `init_expr`.
Some(Stmt::Assign(ast::StmtAssign { targets, value, .. })) => targets
.iter()
.find_map(|target| match_value(binding, target, value))
.is_some_and(|value| T::match_initializer(value, semantic)),
// ```python
// x: annotation = some_expr
// ```
//
// In this situation, we check only the annotation.
Some(Stmt::AnnAssign(ast::StmtAnnAssign { annotation, .. })) => {
T::match_annotation(annotation, semantic)
}
_ => false,
},
BindingKind::NamedExprAssignment => {
// ```python
// if (x := some_expr) is not None:
// ...
// ```
binding.source.is_some_and(|source| {
semantic
.expressions(source)
.find_map(|expr| expr.as_named_expr())
.and_then(|ast::ExprNamed { target, value, .. }| {
match_value(binding, target, value)
})
.is_some_and(|value| T::match_initializer(value, semantic))
})
}
BindingKind::WithItemVar => match binding.statement(semantic) {
// ```python
// with open("file.txt") as x:
// ...
// ```
Some(Stmt::With(ast::StmtWith { items, .. })) => items
.iter()
.find_map(|item| {
let target = item.optional_vars.as_ref()?;
let value = &item.context_expr;
match_value(binding, target, value)
})
.is_some_and(|value| T::match_initializer(value, semantic)),
_ => false,
},
BindingKind::Argument => match binding.statement(semantic) {
// ```python
// def foo(x: annotation):
// ...
// ```
//
// We trust the annotation and see if the type checker matches the annotation.
Some(Stmt::FunctionDef(ast::StmtFunctionDef { parameters, .. })) => {
let Some(parameter) = find_parameter(parameters, binding) else {
return false;
};
let Some(ref annotation) = parameter.parameter.annotation else {
return false;
};
T::match_annotation(annotation, semantic)
}
_ => false,
},
BindingKind::Annotation => match binding.statement(semantic) {
// ```python
// x: annotation
// ```
//
// It's a typed declaration, type annotation is the only source of information.
Some(Stmt::AnnAssign(ast::StmtAnnAssign { annotation, .. })) => {
T::match_annotation(annotation, semantic)
}
_ => false,
},
_ => false,
}
}
/// Type checker for builtin types.
trait BuiltinTypeChecker {
/// Builtin type name.
const BUILTIN_TYPE_NAME: &'static str;
/// Type name as found in the `Typing` module.
const TYPING_NAME: Option<&'static str>;
/// [`PythonType`] associated with the intended type.
const EXPR_TYPE: PythonType;
/// Check annotation expression to match the intended type.
fn match_annotation(annotation: &Expr, semantic: &SemanticModel) -> bool {
let value = map_subscript(annotation);
semantic.match_builtin_expr(value, Self::BUILTIN_TYPE_NAME)
|| Self::TYPING_NAME.is_some_and(|name| semantic.match_typing_expr(value, name))
}
/// Check initializer expression to match the intended type.
fn match_initializer(initializer: &Expr, semantic: &SemanticModel) -> bool {
Self::match_expr_type(initializer) || Self::match_builtin_constructor(initializer, semantic)
}
/// Check if the type can be inferred from the given expression.
fn match_expr_type(initializer: &Expr) -> bool {
let init_type: ResolvedPythonType = initializer.into();
match init_type {
ResolvedPythonType::Atom(atom) => atom == Self::EXPR_TYPE,
_ => false,
}
}
/// Check if the given expression corresponds to a constructor call of the builtin type.
fn match_builtin_constructor(initializer: &Expr, semantic: &SemanticModel) -> bool {
let Expr::Call(ast::ExprCall { func, .. }) = initializer else {
return false;
};
semantic.match_builtin_expr(func, Self::BUILTIN_TYPE_NAME)
}
}
impl<T: BuiltinTypeChecker> TypeChecker for T {
fn match_annotation(annotation: &Expr, semantic: &SemanticModel) -> bool {
<Self as BuiltinTypeChecker>::match_annotation(annotation, semantic)
}
fn match_initializer(initializer: &Expr, semantic: &SemanticModel) -> bool {
<Self as BuiltinTypeChecker>::match_initializer(initializer, semantic)
}
}
struct ListChecker;
impl BuiltinTypeChecker for ListChecker {
const BUILTIN_TYPE_NAME: &'static str = "list";
const TYPING_NAME: Option<&'static str> = Some("List");
const EXPR_TYPE: PythonType = PythonType::List;
}
struct DictChecker;
impl BuiltinTypeChecker for DictChecker {
const BUILTIN_TYPE_NAME: &'static str = "dict";
const TYPING_NAME: Option<&'static str> = Some("Dict");
const EXPR_TYPE: PythonType = PythonType::Dict;
}
struct SetChecker;
impl BuiltinTypeChecker for SetChecker {
const BUILTIN_TYPE_NAME: &'static str = "set";
const TYPING_NAME: Option<&'static str> = Some("Set");
const EXPR_TYPE: PythonType = PythonType::Set;
}
struct TupleChecker;
impl BuiltinTypeChecker for TupleChecker {
const BUILTIN_TYPE_NAME: &'static str = "tuple";
const TYPING_NAME: Option<&'static str> = Some("Tuple");
const EXPR_TYPE: PythonType = PythonType::Tuple;
}
struct IntChecker;
impl BuiltinTypeChecker for IntChecker {
const BUILTIN_TYPE_NAME: &'static str = "int";
const TYPING_NAME: Option<&'static str> = None;
const EXPR_TYPE: PythonType = PythonType::Number(NumberLike::Integer);
}
pub struct IoBaseChecker;
impl TypeChecker for IoBaseChecker {
fn match_annotation(annotation: &Expr, semantic: &SemanticModel) -> bool {
semantic
.resolve_qualified_name(annotation)
.is_some_and(|qualified_name| {
if semantic.match_typing_qualified_name(&qualified_name, "IO") {
return true;
}
if semantic.match_typing_qualified_name(&qualified_name, "BinaryIO") {
return true;
}
if semantic.match_typing_qualified_name(&qualified_name, "TextIO") {
return true;
}
matches!(
qualified_name.segments(),
[
"io",
"IOBase"
| "RawIOBase"
| "BufferedIOBase"
| "TextIOBase"
| "BytesIO"
| "StringIO"
| "BufferedReader"
| "BufferedWriter"
| "BufferedRandom"
| "BufferedRWPair"
| "TextIOWrapper"
] | ["os", "Path" | "PathLike"]
| [
"pathlib",
"Path" | "PurePath" | "PurePosixPath" | "PureWindowsPath"
]
)
})
}
fn match_initializer(initializer: &Expr, semantic: &SemanticModel) -> bool {
let Expr::Call(ast::ExprCall { func, .. }) = initializer else {
return false;
};
// Ex) `pathlib.Path("file.txt")`
if let Expr::Attribute(ast::ExprAttribute { value, attr, .. }) = func.as_ref() {
if attr.as_str() == "open" {
if let Expr::Call(ast::ExprCall { func, .. }) = value.as_ref() {
return semantic
.resolve_qualified_name(func)
.is_some_and(|qualified_name| {
matches!(
qualified_name.segments(),
[
"pathlib",
"Path" | "PurePath" | "PurePosixPath" | "PureWindowsPath"
]
)
});
}
}
}
// Ex) `open("file.txt")`
semantic
.resolve_qualified_name(func)
.is_some_and(|qualified_name| {
matches!(
qualified_name.segments(),
["io", "open" | "open_code"] | ["os" | "" | "builtins", "open"]
)
})
}
}
/// Test whether the given binding can be considered a list.
///
/// For this, we check what value might be associated with it through it's initialization and
/// what annotation it has (we consider `list` and `typing.List`)
pub fn is_list(binding: &Binding, semantic: &SemanticModel) -> bool {
check_type::<ListChecker>(binding, semantic)
}
/// Test whether the given binding can be considered a dictionary.
///
/// For this, we check what value might be associated with it through it's initialization,
/// what annotation it has (we consider `dict` and `typing.Dict`), and if it is a variadic keyword
/// argument parameter.
pub fn is_dict(binding: &Binding, semantic: &SemanticModel) -> bool {
// ```python
// def foo(**kwargs):
// ...
// ```
if matches!(binding.kind, BindingKind::Argument) {
if let Some(Stmt::FunctionDef(ast::StmtFunctionDef { parameters, .. })) =
binding.statement(semantic)
{
if let Some(kwarg_parameter) = parameters.kwarg.as_deref() {
if kwarg_parameter.name.range() == binding.range() {
return true;
}
}
}
}
check_type::<DictChecker>(binding, semantic)
}
/// Test whether the given binding can be considered an integer.
pub fn is_int(binding: &Binding, semantic: &SemanticModel) -> bool {
check_type::<IntChecker>(binding, semantic)
}
/// Test whether the given binding can be considered a set.
///
/// For this, we check what value might be associated with it through it's initialization and
/// what annotation it has (we consider `set` and `typing.Set`).
pub fn is_set(binding: &Binding, semantic: &SemanticModel) -> bool {
check_type::<SetChecker>(binding, semantic)
}
/// Test whether the given binding can be considered a tuple.
///
/// For this, we check what value might be associated with it through it's initialization, what
/// annotation it has (we consider `tuple` and `typing.Tuple`), and if it is a variadic positional
/// argument.
pub fn is_tuple(binding: &Binding, semantic: &SemanticModel) -> bool {
// ```python
// def foo(*args):
// ...
// ```
if matches!(binding.kind, BindingKind::Argument) {
if let Some(Stmt::FunctionDef(ast::StmtFunctionDef { parameters, .. })) =
binding.statement(semantic)
{
if let Some(arg_parameter) = parameters.vararg.as_deref() {
if arg_parameter.name.range() == binding.range() {
return true;
}
}
}
}
check_type::<TupleChecker>(binding, semantic)
}
/// Test whether the given binding can be considered a file-like object (i.e., a type that
/// implements `io.IOBase`).
pub fn is_io_base(binding: &Binding, semantic: &SemanticModel) -> bool {
check_type::<IoBaseChecker>(binding, semantic)
}
/// Test whether the given expression can be considered a file-like object (i.e., a type that
/// implements `io.IOBase`).
pub fn is_io_base_expr(expr: &Expr, semantic: &SemanticModel) -> bool {
IoBaseChecker::match_initializer(expr, semantic)
}
/// Find the [`ParameterWithDefault`] corresponding to the given [`Binding`].
#[inline]
fn find_parameter<'a>(
parameters: &'a Parameters,
binding: &Binding,
) -> Option<&'a ParameterWithDefault> {
parameters
.iter_non_variadic_params()
.find(|arg| arg.parameter.name.range() == binding.range())
}
/// Return the [`QualifiedName`] of the value to which the given [`Expr`] is assigned, if any.
///
/// For example, given:
/// ```python
/// import asyncio
///
/// loop = asyncio.get_running_loop()
/// loop.create_task(...)
/// ```
///
/// This function will return `["asyncio", "get_running_loop"]` for the `loop` binding.
pub fn resolve_assignment<'a>(
expr: &'a Expr,
semantic: &'a SemanticModel<'a>,
) -> Option<QualifiedName<'a>> {
let name = expr.as_name_expr()?;
let binding_id = semantic.resolve_name(name)?;
let statement = semantic.binding(binding_id).statement(semantic)?;
match statement {
Stmt::Assign(ast::StmtAssign { value, .. }) => {
let ast::ExprCall { func, .. } = value.as_call_expr()?;
semantic.resolve_qualified_name(func)
}
Stmt::AnnAssign(ast::StmtAnnAssign {
value: Some(value), ..
}) => {
let ast::ExprCall { func, .. } = value.as_call_expr()?;
semantic.resolve_qualified_name(func)
}
_ => None,
}
}
/// Find the assigned [`Expr`] for a given symbol, if any.
///
/// For example given:
/// ```python
/// foo = 42
/// (bar, bla) = 1, "str"
/// ```
///
/// This function will return a `NumberLiteral` with value `Int(42)` when called with `foo` and a
/// `StringLiteral` with value `"str"` when called with `bla`.
pub fn find_assigned_value<'a>(symbol: &str, semantic: &'a SemanticModel<'a>) -> Option<&'a Expr> {
let binding_id = semantic.lookup_symbol(symbol)?;
let binding = semantic.binding(binding_id);
find_binding_value(binding, semantic)
}
/// Find the assigned [`Expr`] for a given [`Binding`], if any.
///
/// For example given:
/// ```python
/// foo = 42
/// (bar, bla) = 1, "str"
/// ```
///
/// This function will return a `NumberLiteral` with value `Int(42)` when called with `foo` and a
/// `StringLiteral` with value `"str"` when called with `bla`.
#[allow(clippy::single_match)]
pub fn find_binding_value<'a>(binding: &Binding, semantic: &'a SemanticModel) -> Option<&'a Expr> {
match binding.kind {
// Ex) `x := 1`
BindingKind::NamedExprAssignment => {
let parent_id = binding.source?;
let parent = semantic
.expressions(parent_id)
.find_map(|expr| expr.as_named_expr());
if let Some(ast::ExprNamed { target, value, .. }) = parent {
return match_value(binding, target, value);
}
}
// Ex) `x = 1`
BindingKind::Assignment => match binding.statement(semantic) {
Some(Stmt::Assign(ast::StmtAssign { value, targets, .. })) => {
return targets
.iter()
.find_map(|target| match_value(binding, target, value))
}
Some(Stmt::AnnAssign(ast::StmtAnnAssign {
value: Some(value),
target,
..
})) => {
return match_value(binding, target, value);
}
_ => {}
},
// Ex) `with open("file.txt") as f:`
BindingKind::WithItemVar => match binding.statement(semantic) {
Some(Stmt::With(ast::StmtWith { items, .. })) => {
return items.iter().find_map(|item| {
let target = item.optional_vars.as_ref()?;
let value = &item.context_expr;
match_value(binding, target, value)
});
}
_ => {}
},
_ => {}
}
None
}
/// Given a target and value, find the value that's assigned to the given symbol.
fn match_value<'a>(binding: &Binding, target: &Expr, value: &'a Expr) -> Option<&'a Expr> {
match target {
Expr::Name(name) if name.range() == binding.range() => Some(value),
Expr::Tuple(ast::ExprTuple { elts, .. }) | Expr::List(ast::ExprList { elts, .. }) => {
match value {
Expr::Tuple(ast::ExprTuple {
elts: value_elts, ..
})
| Expr::List(ast::ExprList {
elts: value_elts, ..
})
| Expr::Set(ast::ExprSet {
elts: value_elts, ..
}) => match_target(binding, elts, value_elts),
_ => None,
}
}
_ => None,
}
}
/// Given a target and value, find the value that's assigned to the given symbol.
fn match_target<'a>(binding: &Binding, targets: &[Expr], values: &'a [Expr]) -> Option<&'a Expr> {
for (target, value) in targets.iter().zip(values) {
match target {
Expr::Tuple(ast::ExprTuple {
elts: target_elts, ..
})
| Expr::List(ast::ExprList {
elts: target_elts, ..
})
| Expr::Set(ast::ExprSet {
elts: target_elts, ..
}) => {
// Collection types can be mismatched like in: (a, b, [c, d]) = [1, 2, {3, 4}]
match value {
Expr::Tuple(ast::ExprTuple {
elts: value_elts, ..
})
| Expr::List(ast::ExprList {
elts: value_elts, ..
})
| Expr::Set(ast::ExprSet {
elts: value_elts, ..
}) => {
if let Some(result) = match_target(binding, target_elts, value_elts) {
return Some(result);
}
}
_ => (),
};
}
Expr::Name(name) => {
if name.range() == binding.range() {
return Some(value);
}
}
_ => (),
}
}
None
}