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Add `Terminal::RaiseNotImplemented` variant to avoid double traversal 

Changes:
- Add `Terminal::RaiseNotImplemented` enum variant
- Modify `Terminal::from_function()` to accept `SemanticModel` and detect `NotImplementedError` during traversal
- Update `and_then()` and `branch()` combination methods to handle the new variant
- Remove `only_raises_not_implemented_error()` helper function
- Update `auto_return_type()` to check for `Terminal::RaiseNotImplemented` directly
- Update all call sites to pass `SemanticModel` to `Terminal::from_function()`
This commit is contained in:
Dan 2025-11-07 17:59:19 -05:00
parent 32620b80d3
commit 0c87832e8a
8 changed files with 80 additions and 116 deletions
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100
crates/ruff_linter/src/rules/flake8_annotations/helpers.rs
View File

@ -2,7 +2,7 @@ use itertools::Itertools;
use rustc_hash::FxHashSet;
use ruff_python_ast::helpers::{
ReturnStatementVisitor, map_callable, pep_604_union, typing_optional, typing_union,
ReturnStatementVisitor, pep_604_union, typing_optional, typing_union,
};
use ruff_python_ast::name::Name;
use ruff_python_ast::visitor::Visitor;
@ -47,90 +47,6 @@ pub(crate) fn is_overload_impl(
}
}
/// Returns `true` if all raise statements in the function body are `NotImplementedError`.
fn only_raises_not_implemented_error(
function: &ast::StmtFunctionDef,
semantic: &SemanticModel,
) -> bool {
use ruff_python_ast::statement_visitor::{StatementVisitor, walk_body};
struct NotImplementedErrorVisitor<'a> {
raises: Vec<&'a ast::StmtRaise>,
}
impl<'a> StatementVisitor<'a> for NotImplementedErrorVisitor<'a> {
fn visit_stmt(&mut self, stmt: &'a ast::Stmt) {
match stmt {
ast::Stmt::Raise(raise) => {
self.raises.push(raise);
}
ast::Stmt::ClassDef(_) | ast::Stmt::FunctionDef(_) => {
// Don't recurse into nested classes/functions
}
ast::Stmt::If(ast::StmtIf {
body,
elif_else_clauses,
..
}) => {
walk_body(self, body);
for clause in elif_else_clauses {
walk_body(self, &clause.body);
}
}
ast::Stmt::For(ast::StmtFor { body, orelse, .. })
| ast::Stmt::While(ast::StmtWhile { body, orelse, .. }) => {
walk_body(self, body);
walk_body(self, orelse);
}
ast::Stmt::With(ast::StmtWith { body, .. }) => {
walk_body(self, body);
}
ast::Stmt::Match(ast::StmtMatch { cases, .. }) => {
for case in cases {
walk_body(self, &case.body);
}
}
ast::Stmt::Try(ast::StmtTry {
body,
handlers,
orelse,
finalbody,
..
}) => {
walk_body(self, body);
for handler in handlers {
let ast::ExceptHandler::ExceptHandler(ast::ExceptHandlerExceptHandler {
body,
..
}) = handler;
walk_body(self, body);
}
walk_body(self, orelse);
walk_body(self, finalbody);
}
_ => {}
}
}
}
let mut visitor = NotImplementedErrorVisitor { raises: Vec::new() };
walk_body(&mut visitor, &function.body);
// If there are no raises, return false
if visitor.raises.is_empty() {
return false;
}
// Check if all raises are NotImplementedError
visitor.raises.iter().all(|raise| {
raise.exc.as_ref().is_some_and(|exc| {
semantic
.resolve_builtin_symbol(map_callable(exc))
.is_some_and(|name| matches!(name, "NotImplementedError" | "NotImplemented"))
})
})
}
/// Given a function, guess its return type.
pub(crate) fn auto_return_type(
function: &ast::StmtFunctionDef,
@ -150,15 +66,17 @@ pub(crate) fn auto_return_type(
};
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function);
let terminal = Terminal::from_function(function, semantic);
// If every control flow path raises an exception, check if it's NotImplementedError.
// If all raises are NotImplementedError, don't suggest NoReturn since these are
// abstract methods that should have the actual return type.
if terminal == Terminal::Raise {
if only_raises_not_implemented_error(function, semantic) {
// If every control flow path raises NotImplementedError, don't suggest NoReturn
// since these are abstract methods that should have the actual return type.
if terminal == Terminal::RaiseNotImplemented {
return None;
}
// If every control flow path raises an exception (other than NotImplementedError),
// suggest NoReturn.
if terminal == Terminal::Raise {
return Some(AutoPythonType::Never);
}

2
crates/ruff_linter/src/rules/pylint/rules/invalid_bool_return.rs
View File

@ -60,7 +60,7 @@ pub(crate) fn invalid_bool_return(checker: &Checker, function_def: &ast::StmtFun
}
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function_def);
let terminal = Terminal::from_function(function_def, checker.semantic());
// If every control flow path raises an exception, ignore the function.
if terminal == Terminal::Raise {

2
crates/ruff_linter/src/rules/pylint/rules/invalid_bytes_return.rs
View File

@ -60,7 +60,7 @@ pub(crate) fn invalid_bytes_return(checker: &Checker, function_def: &ast::StmtFu
}
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function_def);
let terminal = Terminal::from_function(function_def, checker.semantic());
// If every control flow path raises an exception, ignore the function.
if terminal == Terminal::Raise {

2
crates/ruff_linter/src/rules/pylint/rules/invalid_hash_return.rs
View File

@ -64,7 +64,7 @@ pub(crate) fn invalid_hash_return(checker: &Checker, function_def: &ast::StmtFun
}
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function_def);
let terminal = Terminal::from_function(function_def, checker.semantic());
// If every control flow path raises an exception, ignore the function.
if terminal == Terminal::Raise {

2
crates/ruff_linter/src/rules/pylint/rules/invalid_index_return.rs
View File

@ -66,7 +66,7 @@ pub(crate) fn invalid_index_return(checker: &Checker, function_def: &ast::StmtFu
}
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function_def);
let terminal = Terminal::from_function(function_def, checker.semantic());
// If every control flow path raises an exception, ignore the function.
if terminal == Terminal::Raise {

2
crates/ruff_linter/src/rules/pylint/rules/invalid_length_return.rs
View File

@ -65,7 +65,7 @@ pub(crate) fn invalid_length_return(checker: &Checker, function_def: &ast::StmtF
}
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function_def);
let terminal = Terminal::from_function(function_def, checker.semantic());
// If every control flow path raises an exception, ignore the function.
if terminal == Terminal::Raise {

2
crates/ruff_linter/src/rules/pylint/rules/invalid_str_return.rs
View File

@ -60,7 +60,7 @@ pub(crate) fn invalid_str_return(checker: &Checker, function_def: &ast::StmtFunc
}
// Determine the terminal behavior (i.e., implicit return, no return, etc.).
let terminal = Terminal::from_function(function_def);
let terminal = Terminal::from_function(function_def, checker.semantic());
// If every control flow path raises an exception, ignore the function.
if terminal == Terminal::Raise {

80
crates/ruff_python_semantic/src/analyze/terminal.rs
View File

@ -1,5 +1,8 @@
use ruff_python_ast::helpers::map_callable;
use ruff_python_ast::{self as ast, ExceptHandler, Stmt};
use crate::model::SemanticModel;
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Terminal {
/// There is no known terminal.
@ -8,6 +11,8 @@ pub enum Terminal {
Implicit,
/// Every path through the function ends with a `raise` statement.
Raise,
/// Every path through the function ends with a `raise NotImplementedError` statement.
RaiseNotImplemented,
/// No path through the function ends with a `return` statement.
Return,
/// Every path through the function ends with a `return` or `raise` statement.
@ -18,8 +23,8 @@ pub enum Terminal {
impl Terminal {
/// Returns the [`Terminal`] behavior of the function, if it can be determined.
pub fn from_function(function: &ast::StmtFunctionDef) -> Terminal {
Self::from_body(&function.body)
pub fn from_function(function: &ast::StmtFunctionDef, semantic: &SemanticModel) -> Terminal {
Self::from_body(&function.body, Some(semantic))
}
/// Returns `true` if the [`Terminal`] behavior includes at least one `return` path.
@ -36,7 +41,7 @@ impl Terminal {
}
/// Returns the [`Terminal`] behavior of the body, if it can be determined.
fn from_body(stmts: &[Stmt]) -> Terminal {
fn from_body(stmts: &[Stmt], semantic: Option<&SemanticModel>) -> Terminal {
let mut terminal = Terminal::None;
for stmt in stmts {
@ -47,10 +52,10 @@ impl Terminal {
continue;
}
terminal = terminal.and_then(Self::from_body(body));
terminal = terminal.and_then(Self::from_body(body, semantic));
if !sometimes_breaks(body) {
terminal = terminal.and_then(Self::from_body(orelse));
terminal = terminal.and_then(Self::from_body(orelse, semantic));
}
}
Stmt::If(ast::StmtIf {
@ -59,10 +64,10 @@ impl Terminal {
..
}) => {
let branch_terminal = Terminal::branches(
std::iter::once(Self::from_body(body)).chain(
std::iter::once(Self::from_body(body, semantic)).chain(
elif_else_clauses
.iter()
.map(|clause| Self::from_body(&clause.body)),
.map(|clause| Self::from_body(&clause.body, semantic)),
),
);
@ -79,7 +84,9 @@ impl Terminal {
}
Stmt::Match(ast::StmtMatch { cases, .. }) => {
let branch_terminal = terminal.and_then(Terminal::branches(
cases.iter().map(|case| Self::from_body(&case.body)),
cases
.iter()
.map(|case| Self::from_body(&case.body, semantic)),
));
// If the `match` is known to be exhaustive (by way of including a wildcard
@ -106,21 +113,21 @@ impl Terminal {
// that _any_ statement in the body could raise an exception, so we don't
// consider the body to be exhaustive. In other words, we assume the exception
// handlers exist for a reason.
let body_terminal = Self::from_body(body);
let body_terminal = Self::from_body(body, semantic);
if body_terminal.has_any_return() {
terminal = terminal.and_then(Terminal::ConditionalReturn);
}
// If the `finally` block returns, the `try` block must also return. (Similarly,
// if the `finally` block raises, the `try` block must also raise.)
terminal = terminal.and_then(Self::from_body(finalbody));
terminal = terminal.and_then(Self::from_body(finalbody, semantic));
let branch_terminal = Terminal::branches(handlers.iter().map(|handler| {
let ExceptHandler::ExceptHandler(ast::ExceptHandlerExceptHandler {
body,
..
}) = handler;
Self::from_body(body)
Self::from_body(body, semantic)
}));
if orelse.is_empty() {
@ -132,19 +139,36 @@ impl Terminal {
} else {
// If there's an `else`, we won't fall through. If all the handlers and
// the `else` block return,, the `try` block also returns.
terminal =
terminal.and_then(branch_terminal.branch(Terminal::from_body(orelse)));
terminal = terminal.and_then(
branch_terminal.branch(Terminal::from_body(orelse, semantic)),
);
}
}
Stmt::With(ast::StmtWith { body, .. }) => {
terminal = terminal.and_then(Self::from_body(body));
terminal = terminal.and_then(Self::from_body(body, semantic));
}
Stmt::Return(_) => {
terminal = terminal.and_then(Terminal::RaiseOrReturn);
}
Stmt::Raise(_) => {
Stmt::Raise(raise) => {
// Check if this raise is NotImplementedError (only if semantic model is available)
let is_not_implemented = semantic
.and_then(|sem| {
raise.exc.as_ref().and_then(|exc| {
sem.resolve_builtin_symbol(map_callable(exc))
.filter(|name| {
matches!(*name, "NotImplementedError" | "NotImplemented")
})
})
})
.is_some();
if is_not_implemented {
terminal = terminal.and_then(Terminal::RaiseNotImplemented);
} else {
terminal = terminal.and_then(Terminal::Raise);
}
}
_ => {}
}
}
@ -174,21 +198,32 @@ impl Terminal {
(Self::Raise, Self::ConditionalReturn) => Self::RaiseOrReturn,
(Self::ConditionalReturn, Self::Raise) => Self::RaiseOrReturn,
// If one of the operators is `RaiseNotImplemented`, treat it like `Raise` for combinations
(Self::RaiseNotImplemented, Self::ConditionalReturn) => Self::RaiseOrReturn,
(Self::ConditionalReturn, Self::RaiseNotImplemented) => Self::RaiseOrReturn,
// If one of the operators is `Return`, then the function returns.
(Self::Return, Self::ConditionalReturn) => Self::Return,
(Self::ConditionalReturn, Self::Return) => Self::Return,
// All paths through the function end with a `raise` statement.
(Self::Raise, Self::Raise) => Self::Raise,
// All paths through the function end with a `raise NotImplementedError` statement.
(Self::RaiseNotImplemented, Self::RaiseNotImplemented) => Self::RaiseNotImplemented,
// Mixed raises: if one is NotImplementedError and one is regular Raise, result is Raise
(Self::RaiseNotImplemented, Self::Raise) => Self::Raise,
(Self::Raise, Self::RaiseNotImplemented) => Self::Raise,
// All paths through the function end with a `return` statement.
(Self::Return, Self::Return) => Self::Return,
// All paths through the function end with a `return` or `raise` statement.
(Self::Raise, Self::Return) => Self::RaiseOrReturn,
(Self::RaiseNotImplemented, Self::Return) => Self::RaiseOrReturn,
// All paths through the function end with a `return` or `raise` statement.
(Self::Return, Self::Raise) => Self::RaiseOrReturn,
(Self::Return, Self::RaiseNotImplemented) => Self::RaiseOrReturn,
// All paths through the function end with a `return` or `raise` statement.
(Self::RaiseOrReturn, _) => Self::RaiseOrReturn,
@ -207,6 +242,8 @@ impl Terminal {
(Self::Implicit, Self::Implicit) => Self::Implicit,
(Self::Implicit, Self::Raise) => Self::Implicit,
(Self::Raise, Self::Implicit) => Self::Implicit,
(Self::Implicit, Self::RaiseNotImplemented) => Self::Implicit,
(Self::RaiseNotImplemented, Self::Implicit) => Self::Implicit,
(Self::Implicit, Self::Return) => Self::ConditionalReturn,
(Self::Return, Self::Implicit) => Self::ConditionalReturn,
(Self::Implicit, Self::RaiseOrReturn) => Self::ConditionalReturn,
@ -219,18 +256,27 @@ impl Terminal {
(Self::Raise, Self::ConditionalReturn) => Self::RaiseOrReturn,
(Self::ConditionalReturn, Self::Raise) => Self::RaiseOrReturn,
(Self::RaiseNotImplemented, Self::ConditionalReturn) => Self::RaiseOrReturn,
(Self::ConditionalReturn, Self::RaiseNotImplemented) => Self::RaiseOrReturn,
(Self::Return, Self::ConditionalReturn) => Self::Return,
(Self::ConditionalReturn, Self::Return) => Self::Return,
// All paths through the function end with a `raise` statement.
(Self::Raise, Self::Raise) => Self::Raise,
// All paths through the function end with a `raise NotImplementedError` statement.
(Self::RaiseNotImplemented, Self::RaiseNotImplemented) => Self::RaiseNotImplemented,
// Mixed raises: if one is NotImplementedError and one is regular Raise, result is Raise
(Self::RaiseNotImplemented, Self::Raise) => Self::Raise,
(Self::Raise, Self::RaiseNotImplemented) => Self::Raise,
// All paths through the function end with a `return` statement.
(Self::Return, Self::Return) => Self::Return,
// All paths through the function end with a `return` or `raise` statement.
(Self::Raise, Self::Return) => Self::RaiseOrReturn,
(Self::RaiseNotImplemented, Self::Return) => Self::RaiseOrReturn,
// All paths through the function end with a `return` or `raise` statement.
(Self::Return, Self::Raise) => Self::RaiseOrReturn,
(Self::Return, Self::RaiseNotImplemented) => Self::RaiseOrReturn,
// All paths through the function end with a `return` or `raise` statement.
(Self::RaiseOrReturn, _) => Self::RaiseOrReturn,
(_, Self::RaiseOrReturn) => Self::RaiseOrReturn,
@ -248,7 +294,7 @@ fn sometimes_breaks(stmts: &[Stmt]) -> bool {
for stmt in stmts {
match stmt {
Stmt::For(ast::StmtFor { body, orelse, .. }) => {
if Terminal::from_body(body).has_any_return() {
if Terminal::from_body(body, None).has_any_return() {
return false;
}
if sometimes_breaks(orelse) {
@ -256,7 +302,7 @@ fn sometimes_breaks(stmts: &[Stmt]) -> bool {
}
}
Stmt::While(ast::StmtWhile { body, orelse, .. }) => {
if Terminal::from_body(body).has_any_return() {
if Terminal::from_body(body, None).has_any_return() {
return false;
}
if sometimes_breaks(orelse) {