Files
ruff/src/check_ast.rs
2022-09-29 16:37:43 -04:00

1600 lines
60 KiB
Rust

use std::ops::Deref;
use std::path::Path;
use rustpython_parser::ast::{
Arg, Arguments, Constant, Excepthandler, ExcepthandlerKind, Expr, ExprContext, ExprKind,
KeywordData, Location, Operator, Stmt, StmtKind, Suite,
};
use rustpython_parser::parser;
use crate::ast::operations::{extract_all_names, SourceCodeLocator};
use crate::ast::relocate::relocate_expr;
use crate::ast::types::{Binding, BindingKind, CheckLocator, FunctionScope, Scope, ScopeKind};
use crate::ast::visitor::{walk_excepthandler, Visitor};
use crate::ast::{checks, operations, visitor};
use crate::autofix::fixer;
use crate::checks::{Check, CheckCode, CheckKind};
use crate::python::builtins::{BUILTINS, MAGIC_GLOBALS};
use crate::python::future::ALL_FEATURE_NAMES;
use crate::python::typing;
use crate::settings::Settings;
pub const GLOBAL_SCOPE_INDEX: usize = 0;
struct Checker<'a> {
// Input data.
locator: SourceCodeLocator<'a>,
settings: &'a Settings,
autofix: &'a fixer::Mode,
path: &'a Path,
// Computed checks.
checks: Vec<Check>,
// Retain all scopes and parent nodes, along with a stack of indexes to track which are active
// at various points in time.
parents: Vec<&'a Stmt>,
parent_stack: Vec<usize>,
scopes: Vec<Scope>,
scope_stack: Vec<usize>,
dead_scopes: Vec<usize>,
deferred_string_annotations: Vec<(Location, &'a str)>,
deferred_annotations: Vec<(&'a Expr, Vec<usize>, Vec<usize>)>,
deferred_functions: Vec<(&'a Stmt, Vec<usize>, Vec<usize>)>,
deferred_lambdas: Vec<(&'a Expr, Vec<usize>, Vec<usize>)>,
deferred_assignments: Vec<usize>,
// Derivative state.
in_f_string: Option<Location>,
in_annotation: bool,
in_literal: bool,
seen_non_import: bool,
seen_docstring: bool,
futures_allowed: bool,
annotations_future_enabled: bool,
}
impl<'a> Checker<'a> {
pub fn new(
settings: &'a Settings,
autofix: &'a fixer::Mode,
path: &'a Path,
content: &'a str,
) -> Checker<'a> {
Checker {
settings,
autofix,
path,
locator: SourceCodeLocator::new(content),
checks: vec![],
parents: vec![],
parent_stack: vec![],
scopes: vec![],
scope_stack: vec![],
dead_scopes: vec![],
deferred_string_annotations: vec![],
deferred_annotations: vec![],
deferred_functions: vec![],
deferred_lambdas: vec![],
deferred_assignments: vec![],
in_f_string: None,
in_annotation: false,
in_literal: false,
seen_non_import: false,
seen_docstring: false,
futures_allowed: true,
annotations_future_enabled: false,
}
}
}
fn match_name_or_attr(expr: &Expr, target: &str) -> bool {
match &expr.node {
ExprKind::Attribute { attr, .. } => target == attr,
ExprKind::Name { id, .. } => target == id,
_ => false,
}
}
fn is_annotated_subscript(expr: &Expr) -> bool {
match &expr.node {
ExprKind::Attribute { attr, .. } => typing::is_annotated_subscript(attr),
ExprKind::Name { id, .. } => typing::is_annotated_subscript(id),
_ => false,
}
}
impl<'a, 'b> Visitor<'b> for Checker<'a>
where
'b: 'a,
{
fn visit_stmt(&mut self, stmt: &'b Stmt) {
self.push_parent(stmt);
// Track whether we've seen docstrings, non-imports, etc.
match &stmt.node {
StmtKind::ImportFrom { module, .. } => {
// Allow __future__ imports until we see a non-__future__ import.
if self.futures_allowed {
if let Some(module) = module {
if module != "__future__" {
self.futures_allowed = false;
}
}
}
}
StmtKind::Import { .. } => {
self.futures_allowed = false;
}
StmtKind::Expr { value } => {
if self.seen_docstring
&& !self.seen_non_import
&& !operations::in_nested_block(&self.parent_stack, &self.parents)
{
self.seen_non_import = true;
}
if !self.seen_docstring
&& !operations::in_nested_block(&self.parent_stack, &self.parents)
&& matches!(
&value.node,
ExprKind::Constant {
value: Constant::Str(_),
..
},
)
{
self.seen_docstring = true;
}
// Allow docstrings to interrupt __future__ imports.
if self.futures_allowed
&& !matches!(
&value.node,
ExprKind::Constant {
value: Constant::Str(_),
..
},
)
{
self.futures_allowed = false;
}
}
_ => {
self.futures_allowed = false;
if !self.seen_non_import
&& !operations::in_nested_block(&self.parent_stack, &self.parents)
{
self.seen_non_import = true;
}
}
}
// Pre-visit.
match &stmt.node {
StmtKind::Global { names } | StmtKind::Nonlocal { names } => {
let global_scope_id = self.scopes[GLOBAL_SCOPE_INDEX].id;
let current_scope =
&self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
let current_scope_id = current_scope.id;
if current_scope_id != global_scope_id {
for name in names {
for scope in self.scopes.iter_mut().skip(GLOBAL_SCOPE_INDEX + 1) {
scope.values.insert(
name.to_string(),
Binding {
kind: BindingKind::Assignment,
used: Some((global_scope_id, stmt.location)),
location: stmt.location,
},
);
}
}
}
if self.settings.select.contains(&CheckCode::E741) {
let location = self.locate_check(stmt.location);
self.checks.extend(
names.iter().filter_map(|name| {
checks::check_ambiguous_variable_name(name, location)
}),
);
}
}
StmtKind::Break => {
if self.settings.select.contains(&CheckCode::F701) {
if let Some(check) = checks::check_break_outside_loop(
stmt,
&self.parents,
&self.parent_stack,
self,
) {
self.checks.push(check);
}
}
}
StmtKind::Continue => {
if self.settings.select.contains(&CheckCode::F702) {
if let Some(check) = checks::check_continue_outside_loop(
stmt,
&self.parents,
&self.parent_stack,
self,
) {
self.checks.push(check);
}
}
}
StmtKind::FunctionDef {
name,
decorator_list,
returns,
args,
..
}
| StmtKind::AsyncFunctionDef {
name,
decorator_list,
returns,
args,
..
} => {
if self.settings.select.contains(&CheckCode::E743) {
if let Some(check) = checks::check_ambiguous_function_name(
name,
self.locate_check(stmt.location),
) {
self.checks.push(check);
}
}
self.check_builtin_shadowing(name, stmt.location, true);
for expr in decorator_list {
self.visit_expr(expr);
}
for arg in &args.posonlyargs {
if let Some(expr) = &arg.node.annotation {
self.visit_annotation(expr);
}
}
for arg in &args.args {
if let Some(expr) = &arg.node.annotation {
self.visit_annotation(expr);
}
}
if let Some(arg) = &args.vararg {
if let Some(expr) = &arg.node.annotation {
self.visit_annotation(expr);
}
}
for arg in &args.kwonlyargs {
if let Some(expr) = &arg.node.annotation {
self.visit_annotation(expr);
}
}
if let Some(arg) = &args.kwarg {
if let Some(expr) = &arg.node.annotation {
self.visit_annotation(expr);
}
}
for expr in returns {
self.visit_annotation(expr);
}
for expr in &args.kw_defaults {
self.visit_expr(expr);
}
for expr in &args.defaults {
self.visit_expr(expr);
}
self.add_binding(
name.to_string(),
Binding {
kind: BindingKind::Definition,
used: None,
location: stmt.location,
},
);
}
StmtKind::Return { .. } => {
if self
.settings
.select
.contains(CheckKind::ReturnOutsideFunction.code())
{
if let Some(scope_index) = self.scope_stack.last().cloned() {
match self.scopes[scope_index].kind {
ScopeKind::Class | ScopeKind::Module => {
self.checks.push(Check::new(
CheckKind::ReturnOutsideFunction,
self.locate_check(stmt.location),
));
}
_ => {}
}
}
}
}
StmtKind::ClassDef {
name,
bases,
keywords,
decorator_list,
..
} => {
if self.settings.select.contains(&CheckCode::R001) {
let scope =
&self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
if let Some(check) = checks::check_useless_object_inheritance(
stmt,
name,
bases,
keywords,
scope,
&mut self.locator,
self.autofix,
) {
self.checks.push(check);
}
}
if self.settings.select.contains(&CheckCode::E742) {
if let Some(check) =
checks::check_ambiguous_class_name(name, self.locate_check(stmt.location))
{
self.checks.push(check);
}
}
self.check_builtin_shadowing(name, self.locate_check(stmt.location), false);
for expr in bases {
self.visit_expr(expr)
}
for keyword in keywords {
self.visit_keyword(keyword)
}
for expr in decorator_list {
self.visit_expr(expr)
}
self.push_scope(Scope::new(ScopeKind::Class))
}
StmtKind::Import { names } => {
if self
.settings
.select
.contains(CheckKind::ModuleImportNotAtTopOfFile.code())
&& self.seen_non_import
&& stmt.location.column() == 1
{
self.checks.push(Check::new(
CheckKind::ModuleImportNotAtTopOfFile,
self.locate_check(stmt.location),
));
}
for alias in names {
if alias.node.name.contains('.') && alias.node.asname.is_none() {
// TODO(charlie): Multiple submodule imports with the same parent module
// will be merged into a single binding.
self.add_binding(
alias.node.name.split('.').next().unwrap().to_string(),
Binding {
kind: BindingKind::SubmoduleImportation(
alias.node.name.to_string(),
),
used: None,
location: stmt.location,
},
)
} else {
if let Some(asname) = &alias.node.asname {
self.check_builtin_shadowing(asname, stmt.location, false);
}
self.add_binding(
alias
.node
.asname
.clone()
.unwrap_or_else(|| alias.node.name.clone()),
Binding {
kind: BindingKind::Importation(
alias
.node
.asname
.clone()
.unwrap_or_else(|| alias.node.name.clone()),
),
used: None,
location: stmt.location,
},
)
}
}
}
StmtKind::ImportFrom {
names,
module,
level,
} => {
if self
.settings
.select
.contains(CheckKind::ModuleImportNotAtTopOfFile.code())
&& self.seen_non_import
&& stmt.location.column() == 1
{
self.checks.push(Check::new(
CheckKind::ModuleImportNotAtTopOfFile,
self.locate_check(stmt.location),
));
}
for alias in names {
let name = alias
.node
.asname
.clone()
.unwrap_or_else(|| alias.node.name.clone());
if let Some("__future__") = module.as_deref() {
self.add_binding(
name,
Binding {
kind: BindingKind::FutureImportation,
used: Some((
self.scopes[*(self
.scope_stack
.last()
.expect("No current scope found."))]
.id,
stmt.location,
)),
location: stmt.location,
},
);
if alias.node.name == "annotations" {
self.annotations_future_enabled = true;
}
if self.settings.select.contains(&CheckCode::F407)
&& !ALL_FEATURE_NAMES.contains(&alias.node.name.deref())
{
self.checks.push(Check::new(
CheckKind::FutureFeatureNotDefined(alias.node.name.to_string()),
self.locate_check(stmt.location),
));
}
if self.settings.select.contains(&CheckCode::F404) && !self.futures_allowed
{
self.checks.push(Check::new(
CheckKind::LateFutureImport,
self.locate_check(stmt.location),
));
}
} else if alias.node.name == "*" {
let module_name = format!(
"{}{}",
".".repeat(level.unwrap_or_default()),
module.clone().unwrap_or_else(|| "module".to_string()),
);
self.add_binding(
module_name.to_string(),
Binding {
kind: BindingKind::StarImportation,
used: None,
location: stmt.location,
},
);
if self.settings.select.contains(&CheckCode::F406) {
let scope = &self.scopes
[*(self.scope_stack.last().expect("No current scope found."))];
if !matches!(scope.kind, ScopeKind::Module) {
self.checks.push(Check::new(
CheckKind::ImportStarNotPermitted(module_name.to_string()),
self.locate_check(stmt.location),
));
}
}
if self.settings.select.contains(&CheckCode::F403) {
self.checks.push(Check::new(
CheckKind::ImportStarUsed(module_name.to_string()),
self.locate_check(stmt.location),
));
}
let scope = &mut self.scopes[*(self
.scope_stack
.last_mut()
.expect("No current scope found."))];
scope.import_starred = true;
} else {
if let Some(asname) = &alias.node.asname {
self.check_builtin_shadowing(asname, stmt.location, false);
}
let binding = Binding {
kind: BindingKind::Importation(match module {
None => name.clone(),
Some(parent) => format!("{}.{}", parent, name),
}),
used: None,
location: stmt.location,
};
self.add_binding(name, binding)
}
}
}
StmtKind::Raise { exc, .. } => {
if self.settings.select.contains(&CheckCode::F901) {
if let Some(expr) = exc {
if let Some(check) = checks::check_raise_not_implemented(expr) {
self.checks.push(check);
}
}
}
}
StmtKind::AugAssign { target, .. } => {
self.handle_node_load(target);
}
StmtKind::If { test, .. } => {
if self.settings.select.contains(&CheckCode::F634) {
if let Some(check) =
checks::check_if_tuple(test, self.locate_check(stmt.location))
{
self.checks.push(check);
}
}
}
StmtKind::Assert { test, .. } => {
if self.settings.select.contains(CheckKind::AssertTuple.code()) {
if let Some(check) =
checks::check_assert_tuple(test, self.locate_check(stmt.location))
{
self.checks.push(check);
}
}
}
StmtKind::Try { handlers, .. } => {
if self.settings.select.contains(&CheckCode::F707) {
if let Some(check) = checks::check_default_except_not_last(handlers) {
self.checks.push(check);
}
}
}
StmtKind::Assign { value, .. } => {
if self.settings.select.contains(&CheckCode::E731) {
if let Some(check) =
checks::check_do_not_assign_lambda(value, self.locate_check(stmt.location))
{
self.checks.push(check);
}
}
}
StmtKind::AnnAssign { value, .. } => {
if self.settings.select.contains(&CheckCode::E731) {
if let Some(value) = value {
if let Some(check) = checks::check_do_not_assign_lambda(
value,
self.locate_check(stmt.location),
) {
self.checks.push(check);
}
}
}
}
StmtKind::Delete { .. } => {}
_ => {}
}
// Recurse.
match &stmt.node {
StmtKind::FunctionDef { .. } | StmtKind::AsyncFunctionDef { .. } => {
self.deferred_functions.push((
stmt,
self.scope_stack.clone(),
self.parent_stack.clone(),
));
}
StmtKind::ClassDef { body, .. } => {
for stmt in body {
self.visit_stmt(stmt);
}
}
_ => visitor::walk_stmt(self, stmt),
};
// Post-visit.
if let StmtKind::ClassDef { name, .. } = &stmt.node {
self.pop_scope();
self.add_binding(
name.to_string(),
Binding {
kind: BindingKind::ClassDefinition,
used: None,
location: stmt.location,
},
);
};
self.pop_parent();
}
fn visit_annotation(&mut self, expr: &'b Expr) {
let prev_in_annotation = self.in_annotation;
self.in_annotation = true;
self.visit_expr(expr);
self.in_annotation = prev_in_annotation;
}
fn visit_expr(&mut self, expr: &'b Expr) {
let prev_in_f_string = self.in_f_string;
let prev_in_literal = self.in_literal;
let prev_in_annotation = self.in_annotation;
if self.in_annotation && self.annotations_future_enabled {
self.deferred_annotations.push((
expr,
self.scope_stack.clone(),
self.parent_stack.clone(),
));
visitor::walk_expr(self, expr);
return;
}
// Pre-visit.
match &expr.node {
ExprKind::Subscript { value, .. } => {
if match_name_or_attr(value, "Literal") {
self.in_literal = true;
}
}
ExprKind::Tuple { elts, ctx } | ExprKind::List { elts, ctx } => {
if matches!(ctx, ExprContext::Store) {
let check_too_many_expressions =
self.settings.select.contains(&CheckCode::F621);
let check_two_starred_expressions =
self.settings.select.contains(&CheckCode::F622);
if let Some(check) = checks::check_starred_expressions(
elts,
check_too_many_expressions,
check_two_starred_expressions,
self.locate_check(expr.location),
) {
self.checks.push(check);
}
}
}
ExprKind::Name { id, ctx } => match ctx {
ExprContext::Load => self.handle_node_load(expr),
ExprContext::Store => {
if self.settings.select.contains(&CheckCode::E741) {
if let Some(check) = checks::check_ambiguous_variable_name(
id,
self.locate_check(expr.location),
) {
self.checks.push(check);
}
}
self.check_builtin_shadowing(id, expr.location, true);
let parent =
self.parents[*(self.parent_stack.last().expect("No parent found."))];
self.handle_node_store(expr, parent);
}
ExprContext::Del => self.handle_node_delete(expr),
},
ExprKind::Call { func, .. } => {
if self.settings.select.contains(&CheckCode::R002) {
if let Some(check) = checks::check_assert_equals(func, self.autofix) {
self.checks.push(check)
}
}
if let ExprKind::Name { id, ctx } = &func.node {
if id == "locals" && matches!(ctx, ExprContext::Load) {
let scope = &mut self.scopes[*(self
.scope_stack
.last_mut()
.expect("No current scope found."))];
if matches!(
scope.kind,
ScopeKind::Function(FunctionScope { uses_locals: false })
) {
scope.kind = ScopeKind::Function(FunctionScope { uses_locals: true });
}
}
}
}
ExprKind::Dict { keys, .. } => {
let check_repeated_literals = self.settings.select.contains(&CheckCode::F601);
let check_repeated_variables = self.settings.select.contains(&CheckCode::F602);
if check_repeated_literals || check_repeated_variables {
self.checks.extend(checks::check_repeated_keys(
keys,
check_repeated_literals,
check_repeated_variables,
self,
));
}
}
ExprKind::Yield { .. } | ExprKind::YieldFrom { .. } | ExprKind::Await { .. } => {
let scope =
&self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
if self
.settings
.select
.contains(CheckKind::YieldOutsideFunction.code())
&& matches!(scope.kind, ScopeKind::Class | ScopeKind::Module)
{
self.checks.push(Check::new(
CheckKind::YieldOutsideFunction,
self.locate_check(expr.location),
));
}
}
ExprKind::JoinedStr { values } => {
if self.in_f_string.is_none()
&& self
.settings
.select
.contains(CheckKind::FStringMissingPlaceholders.code())
&& !values
.iter()
.any(|value| matches!(value.node, ExprKind::FormattedValue { .. }))
{
self.checks.push(Check::new(
CheckKind::FStringMissingPlaceholders,
self.locate_check(expr.location),
));
}
self.in_f_string = Some(expr.location);
}
ExprKind::BinOp {
left,
op: Operator::RShift,
..
} => {
if self.settings.select.contains(&CheckCode::F633) {
if let ExprKind::Name { id, .. } = &left.node {
if id == "print" {
let scope = &self.scopes
[*(self.scope_stack.last().expect("No current scope found."))];
if let Some(Binding {
kind: BindingKind::Builtin,
..
}) = scope.values.get("print")
{
self.checks
.push(Check::new(CheckKind::InvalidPrintSyntax, left.location));
}
}
}
}
}
ExprKind::UnaryOp { op, operand } => {
let check_not_in = self.settings.select.contains(&CheckCode::E713);
let check_not_is = self.settings.select.contains(&CheckCode::E714);
if check_not_in || check_not_is {
self.checks.extend(checks::check_not_tests(
op,
operand,
check_not_in,
check_not_is,
self,
));
}
}
ExprKind::Compare {
left,
ops,
comparators,
} => {
let check_none_comparisons = self.settings.select.contains(&CheckCode::E711);
let check_true_false_comparisons = self.settings.select.contains(&CheckCode::E712);
if check_none_comparisons || check_true_false_comparisons {
self.checks.extend(checks::check_literal_comparisons(
left,
ops,
comparators,
check_none_comparisons,
check_true_false_comparisons,
self,
));
}
if self.settings.select.contains(&CheckCode::F632) {
self.checks.extend(checks::check_is_literal(
left,
ops,
comparators,
self.locate_check(expr.location),
));
}
if self.settings.select.contains(&CheckCode::E721) {
self.checks.extend(checks::check_type_comparison(
ops,
comparators,
self.locate_check(expr.location),
));
}
}
ExprKind::Constant {
value: Constant::Str(value),
..
} if self.in_annotation && !self.in_literal => {
self.deferred_string_annotations
.push((expr.location, value));
}
ExprKind::GeneratorExp { .. }
| ExprKind::ListComp { .. }
| ExprKind::DictComp { .. }
| ExprKind::SetComp { .. } => self.push_scope(Scope::new(ScopeKind::Generator)),
_ => {}
};
// Recurse.
match &expr.node {
ExprKind::Lambda { .. } => {
self.deferred_lambdas.push((
expr,
self.scope_stack.clone(),
self.parent_stack.clone(),
));
}
ExprKind::Call {
func,
args,
keywords,
} => {
if match_name_or_attr(func, "ForwardRef") {
self.visit_expr(func);
for expr in args {
self.visit_annotation(expr);
}
} else if match_name_or_attr(func, "cast") {
self.visit_expr(func);
if !args.is_empty() {
self.visit_annotation(&args[0]);
}
for expr in args.iter().skip(1) {
self.visit_expr(expr);
}
} else if match_name_or_attr(func, "NewType") {
self.visit_expr(func);
for expr in args.iter().skip(1) {
self.visit_annotation(expr);
}
} else if match_name_or_attr(func, "TypeVar") {
self.visit_expr(func);
for expr in args.iter().skip(1) {
self.visit_annotation(expr);
}
for keyword in keywords {
let KeywordData { arg, value } = &keyword.node;
if let Some(id) = arg {
if id == "bound" {
self.visit_annotation(value);
} else {
self.in_annotation = false;
self.visit_expr(value);
self.in_annotation = prev_in_annotation;
}
}
}
} else if match_name_or_attr(func, "NamedTuple") {
self.visit_expr(func);
// Ex) NamedTuple("a", [("a", int)])
if args.len() > 1 {
match &args[1].node {
ExprKind::List { elts, .. } | ExprKind::Tuple { elts, .. } => {
for elt in elts {
match &elt.node {
ExprKind::List { elts, .. }
| ExprKind::Tuple { elts, .. } => {
if elts.len() == 2 {
self.in_annotation = false;
self.visit_expr(&elts[0]);
self.in_annotation = prev_in_annotation;
self.visit_annotation(&elts[1]);
}
}
_ => {}
}
}
}
_ => {}
}
}
// Ex) NamedTuple("a", a=int)
for keyword in keywords {
let KeywordData { value, .. } = &keyword.node;
self.visit_annotation(value);
}
} else if match_name_or_attr(func, "TypedDict") {
self.visit_expr(func);
// Ex) TypedDict("a", {"a": int})
if args.len() > 1 {
if let ExprKind::Dict { keys, values } = &args[1].node {
for key in keys {
self.in_annotation = false;
self.visit_expr(key);
self.in_annotation = prev_in_annotation;
}
for value in values {
self.visit_annotation(value);
}
}
}
// Ex) TypedDict("a", a=int)
for keyword in keywords {
let KeywordData { value, .. } = &keyword.node;
self.visit_annotation(value);
}
} else {
visitor::walk_expr(self, expr);
}
}
ExprKind::Subscript { value, slice, ctx } => {
if is_annotated_subscript(value) {
self.visit_expr(value);
self.visit_annotation(slice);
self.visit_expr_context(ctx);
} else {
visitor::walk_expr(self, expr);
}
}
_ => visitor::walk_expr(self, expr),
}
// Post-visit.
match &expr.node {
ExprKind::GeneratorExp { .. }
| ExprKind::ListComp { .. }
| ExprKind::DictComp { .. }
| ExprKind::SetComp { .. } => {
self.pop_scope();
}
_ => {}
};
self.in_annotation = prev_in_annotation;
self.in_literal = prev_in_literal;
self.in_f_string = prev_in_f_string;
}
fn visit_excepthandler(&mut self, excepthandler: &'b Excepthandler) {
match &excepthandler.node {
ExcepthandlerKind::ExceptHandler { type_, name, .. } => {
if self.settings.select.contains(&CheckCode::E722) && type_.is_none() {
self.checks.push(Check::new(
CheckKind::DoNotUseBareExcept,
excepthandler.location,
));
}
match name {
Some(name) => {
if self.settings.select.contains(&CheckCode::E741) {
if let Some(check) = checks::check_ambiguous_variable_name(
name,
self.locate_check(excepthandler.location),
) {
self.checks.push(check);
}
}
self.check_builtin_shadowing(name, excepthandler.location, false);
let scope = &self.scopes
[*(self.scope_stack.last().expect("No current scope found."))];
if scope.values.contains_key(name) {
let parent = self.parents
[*(self.parent_stack.last().expect("No parent found."))];
self.handle_node_store(
&Expr::new(
excepthandler.location,
ExprKind::Name {
id: name.to_string(),
ctx: ExprContext::Store,
},
),
parent,
);
self.parents.push(parent);
}
let parent =
self.parents[*(self.parent_stack.last().expect("No parent found."))];
let scope = &self.scopes
[*(self.scope_stack.last().expect("No current scope found."))];
let definition = scope.values.get(name).cloned();
self.handle_node_store(
&Expr::new(
excepthandler.location,
ExprKind::Name {
id: name.to_string(),
ctx: ExprContext::Store,
},
),
parent,
);
self.parents.push(parent);
walk_excepthandler(self, excepthandler);
let scope = &mut self.scopes
[*(self.scope_stack.last().expect("No current scope found."))];
if let Some(binding) = &scope.values.remove(name) {
if self.settings.select.contains(&CheckCode::F841)
&& binding.used.is_none()
{
self.checks.push(Check::new(
CheckKind::UnusedVariable(name.to_string()),
excepthandler.location,
));
}
}
if let Some(binding) = definition {
scope.values.insert(name.to_string(), binding);
}
}
None => walk_excepthandler(self, excepthandler),
}
}
}
}
fn visit_arguments(&mut self, arguments: &'b Arguments) {
if self.settings.select.contains(&CheckCode::F831) {
self.checks
.extend(checks::check_duplicate_arguments(arguments));
}
// Bind, but intentionally avoid walking default expressions, as we handle them upstream.
for arg in &arguments.posonlyargs {
self.visit_arg(arg);
}
for arg in &arguments.args {
self.visit_arg(arg);
}
if let Some(arg) = &arguments.vararg {
self.visit_arg(arg);
}
for arg in &arguments.kwonlyargs {
self.visit_arg(arg);
}
if let Some(arg) = &arguments.kwarg {
self.visit_arg(arg);
}
}
fn visit_arg(&mut self, arg: &'b Arg) {
// Bind, but intentionally avoid walking the annotation, as we handle it upstream.
self.add_binding(
arg.node.arg.to_string(),
Binding {
kind: BindingKind::Argument,
used: None,
location: arg.location,
},
);
if self.settings.select.contains(&CheckCode::E741) {
if let Some(check) = checks::check_ambiguous_variable_name(
&arg.node.arg,
self.locate_check(arg.location),
) {
self.checks.push(check);
}
}
self.check_builtin_arg_shadowing(&arg.node.arg, arg.location);
}
}
impl CheckLocator for Checker<'_> {
fn locate_check(&self, default: Location) -> Location {
self.in_f_string.unwrap_or(default)
}
}
impl<'a> Checker<'a> {
fn push_parent(&mut self, parent: &'a Stmt) {
self.parent_stack.push(self.parents.len());
self.parents.push(parent);
}
fn pop_parent(&mut self) {
self.parent_stack
.pop()
.expect("Attempted to pop without scope.");
}
fn push_scope(&mut self, scope: Scope) {
self.scope_stack.push(self.scopes.len());
self.scopes.push(scope);
}
fn pop_scope(&mut self) {
self.dead_scopes.push(
self.scope_stack
.pop()
.expect("Attempted to pop without scope."),
);
}
fn bind_builtins(&mut self) {
let scope = &mut self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
for builtin in BUILTINS {
scope.values.insert(
(*builtin).to_string(),
Binding {
kind: BindingKind::Builtin,
location: Default::default(),
used: None,
},
);
}
for builtin in MAGIC_GLOBALS {
scope.values.insert(
(*builtin).to_string(),
Binding {
kind: BindingKind::Builtin,
location: Default::default(),
used: None,
},
);
}
}
fn add_binding(&mut self, name: String, binding: Binding) {
let scope = &mut self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
// TODO(charlie): Don't treat annotations as assignments if there is an existing value.
let binding = match scope.values.get(&name) {
None => binding,
Some(existing) => {
if self.settings.select.contains(&CheckCode::F402)
&& matches!(existing.kind, BindingKind::Importation(_))
&& matches!(binding.kind, BindingKind::LoopVar)
{
self.checks.push(Check::new(
CheckKind::ImportShadowedByLoopVar(name.clone(), existing.location.row()),
binding.location,
));
}
Binding {
kind: binding.kind,
location: binding.location,
used: existing.used,
}
}
};
scope.values.insert(name, binding);
}
fn handle_node_load(&mut self, expr: &Expr) {
if let ExprKind::Name { id, .. } = &expr.node {
let scope_id =
self.scopes[*(self.scope_stack.last().expect("No current scope found."))].id;
let mut first_iter = true;
let mut in_generator = false;
let mut import_starred = false;
for scope_index in self.scope_stack.iter().rev() {
let scope = &mut self.scopes[*scope_index];
if matches!(scope.kind, ScopeKind::Class) {
if id == "__class__" {
return;
} else if !first_iter && !in_generator {
continue;
}
}
if let Some(binding) = scope.values.get_mut(id) {
binding.used = Some((scope_id, expr.location));
return;
}
first_iter = false;
in_generator = matches!(scope.kind, ScopeKind::Generator);
import_starred = import_starred || scope.import_starred;
}
if import_starred {
if self.settings.select.contains(&CheckCode::F405) {
let mut from_list = vec![];
for scope_index in self.scope_stack.iter().rev() {
let scope = &self.scopes[*scope_index];
for (name, binding) in scope.values.iter() {
if matches!(binding.kind, BindingKind::StarImportation) {
from_list.push(name.as_str());
}
}
}
from_list.sort();
self.checks.push(Check::new(
CheckKind::ImportStarUsage(id.clone(), from_list.join(", ")),
self.locate_check(expr.location),
));
}
return;
}
if self.settings.select.contains(&CheckCode::F821) {
// Allow __path__.
if self.path.ends_with("__init__.py") && id == "__path__" {
return;
}
self.checks.push(Check::new(
CheckKind::UndefinedName(id.clone()),
self.locate_check(expr.location),
))
}
}
}
fn handle_node_store(&mut self, expr: &Expr, parent: &Stmt) {
if let ExprKind::Name { id, .. } = &expr.node {
let current =
&self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
if self.settings.select.contains(&CheckCode::F823)
&& matches!(current.kind, ScopeKind::Function(_))
&& !current.values.contains_key(id)
{
for scope in self.scopes.iter().rev().skip(1) {
if matches!(scope.kind, ScopeKind::Function(_) | ScopeKind::Module) {
if let Some(binding) = scope.values.get(id) {
if let Some((scope_id, location)) = binding.used {
if scope_id == current.id {
self.checks.push(Check::new(
CheckKind::UndefinedLocal(id.clone()),
self.locate_check(location),
));
}
}
}
}
}
}
if matches!(parent.node, StmtKind::AnnAssign { value: None, .. }) {
self.add_binding(
id.to_string(),
Binding {
kind: BindingKind::Annotation,
used: None,
location: expr.location,
},
);
return;
}
// TODO(charlie): Include comprehensions here.
if matches!(
parent.node,
StmtKind::For { .. } | StmtKind::AsyncFor { .. }
) {
self.add_binding(
id.to_string(),
Binding {
kind: BindingKind::LoopVar,
used: None,
location: expr.location,
},
);
return;
}
if operations::is_unpacking_assignment(parent) {
self.add_binding(
id.to_string(),
Binding {
kind: BindingKind::Binding,
used: None,
location: expr.location,
},
);
return;
}
if id == "__all__"
&& matches!(current.kind, ScopeKind::Module)
&& matches!(
parent.node,
StmtKind::Assign { .. }
| StmtKind::AugAssign { .. }
| StmtKind::AnnAssign { .. }
)
{
self.add_binding(
id.to_string(),
Binding {
kind: BindingKind::Export(extract_all_names(parent, current)),
used: None,
location: expr.location,
},
);
return;
}
self.add_binding(
id.to_string(),
Binding {
kind: BindingKind::Assignment,
used: None,
location: expr.location,
},
);
}
}
fn handle_node_delete(&mut self, expr: &Expr) {
if let ExprKind::Name { id, .. } = &expr.node {
// Check if we're on a conditional branch.
if operations::on_conditional_branch(&self.parent_stack, &self.parents) {
return;
}
let scope =
&mut self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
if scope.values.remove(id).is_none() && self.settings.select.contains(&CheckCode::F821)
{
self.checks.push(Check::new(
CheckKind::UndefinedName(id.clone()),
self.locate_check(expr.location),
))
}
}
}
fn check_deferred_annotations(&mut self) {
while let Some((expr, scopes, parents)) = self.deferred_annotations.pop() {
self.parent_stack = parents;
self.scope_stack = scopes;
self.visit_expr(expr);
}
}
fn check_deferred_string_annotations<'b>(&mut self, allocator: &'b mut Vec<Expr>)
where
'b: 'a,
{
while let Some((location, expression)) = self.deferred_string_annotations.pop() {
if let Ok(mut expr) = parser::parse_expression(expression, "<filename>") {
relocate_expr(&mut expr, location);
allocator.push(expr);
} else if self.settings.select.contains(&CheckCode::F722) {
self.checks.push(Check::new(
CheckKind::ForwardAnnotationSyntaxError(expression.to_string()),
self.locate_check(location),
));
}
}
for expr in allocator {
self.visit_expr(expr);
}
}
fn check_deferred_functions(&mut self) {
while let Some((stmt, scopes, parents)) = self.deferred_functions.pop() {
self.parent_stack = parents;
self.scope_stack = scopes;
self.push_scope(Scope::new(ScopeKind::Function(Default::default())));
match &stmt.node {
StmtKind::FunctionDef { body, args, .. }
| StmtKind::AsyncFunctionDef { body, args, .. } => {
self.visit_arguments(args);
for stmt in body {
self.visit_stmt(stmt);
}
}
_ => {}
}
self.deferred_assignments
.push(*self.scope_stack.last().expect("No current scope found."));
self.pop_scope();
}
}
fn check_deferred_lambdas(&mut self) {
while let Some((expr, scopes, parents)) = self.deferred_lambdas.pop() {
self.parent_stack = parents;
self.scope_stack = scopes;
self.push_scope(Scope::new(ScopeKind::Function(Default::default())));
if let ExprKind::Lambda { args, body } = &expr.node {
self.visit_arguments(args);
self.visit_expr(body);
}
self.deferred_assignments
.push(*self.scope_stack.last().expect("No current scope found."));
self.pop_scope();
}
}
fn check_deferred_assignments(&mut self) {
if self.settings.select.contains(&CheckCode::F841) {
while let Some(index) = self.deferred_assignments.pop() {
self.checks.extend(checks::check_unused_variables(
&self.scopes[index],
self,
&self.settings.dummy_variable_rgx,
));
}
}
}
fn check_dead_scopes(&mut self) {
if !self.settings.select.contains(&CheckCode::F401)
&& !self.settings.select.contains(&CheckCode::F405)
&& !self.settings.select.contains(&CheckCode::F822)
{
return;
}
for index in self.dead_scopes.iter().copied() {
let scope = &self.scopes[index];
let all_binding = scope.values.get("__all__");
let all_names = all_binding.and_then(|binding| match &binding.kind {
BindingKind::Export(names) => Some(names),
_ => None,
});
if self.settings.select.contains(&CheckCode::F822)
&& !scope.import_starred
&& !self.path.ends_with("__init__.py")
{
if let Some(all_binding) = all_binding {
if let Some(names) = all_names {
for name in names {
if !scope.values.contains_key(name) {
self.checks.push(Check::new(
CheckKind::UndefinedExport(name.to_string()),
self.locate_check(all_binding.location),
));
}
}
}
}
}
if self.settings.select.contains(&CheckCode::F405) && scope.import_starred {
if let Some(all_binding) = all_binding {
if let Some(names) = all_names {
let mut from_list = vec![];
for (name, binding) in scope.values.iter() {
if matches!(binding.kind, BindingKind::StarImportation) {
from_list.push(name.as_str());
}
}
from_list.sort();
for name in names {
if !scope.values.contains_key(name) {
self.checks.push(Check::new(
CheckKind::ImportStarUsage(name.clone(), from_list.join(", ")),
self.locate_check(all_binding.location),
));
}
}
}
}
}
if self.settings.select.contains(&CheckCode::F401) {
for (name, binding) in scope.values.iter().rev() {
let used = binding.used.is_some()
|| all_names
.map(|names| names.contains(name))
.unwrap_or_default();
if !used {
match &binding.kind {
BindingKind::Importation(full_name)
| BindingKind::SubmoduleImportation(full_name) => {
self.checks.push(Check::new(
CheckKind::UnusedImport(full_name.to_string()),
self.locate_check(binding.location),
));
}
_ => {}
}
}
}
}
}
}
fn check_builtin_shadowing(&mut self, name: &str, location: Location, is_attribute: bool) {
let scope = &self.scopes[*(self.scope_stack.last().expect("No current scope found."))];
// flake8-builtins
if is_attribute
&& matches!(scope.kind, ScopeKind::Class)
&& self.settings.select.contains(&CheckCode::A003)
{
if let Some(check) = checks::check_builtin_shadowing(
name,
self.locate_check(location),
checks::ShadowingType::Attribute,
) {
self.checks.push(check);
}
} else if self.settings.select.contains(&CheckCode::A001) {
if let Some(check) = checks::check_builtin_shadowing(
name,
self.locate_check(location),
checks::ShadowingType::Variable,
) {
self.checks.push(check);
}
}
}
fn check_builtin_arg_shadowing(&mut self, name: &str, location: Location) {
if self.settings.select.contains(&CheckCode::A002) {
if let Some(check) = checks::check_builtin_shadowing(
name,
self.locate_check(location),
checks::ShadowingType::Argument,
) {
self.checks.push(check);
}
}
}
}
pub fn check_ast(
python_ast: &Suite,
content: &str,
settings: &Settings,
autofix: &fixer::Mode,
path: &Path,
) -> Vec<Check> {
let mut checker = Checker::new(settings, autofix, path, content);
checker.push_scope(Scope::new(ScopeKind::Module));
checker.bind_builtins();
// Iterate over the AST.
for stmt in python_ast {
checker.visit_stmt(stmt);
}
// Check any deferred statements.
checker.check_deferred_functions();
checker.check_deferred_lambdas();
checker.check_deferred_assignments();
checker.check_deferred_annotations();
let mut allocator = vec![];
checker.check_deferred_string_annotations(&mut allocator);
// Reset the scope to module-level, and check all consumed scopes.
checker.scope_stack = vec![GLOBAL_SCOPE_INDEX];
checker.pop_scope();
checker.check_dead_scopes();
checker.checks
}