Python
/
ruff
mirror of https://github.com/astral-sh/ruff
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

[ty] Handle cycles when finding implicit attributes (#19833) 

The [minimal
reproduction](https://gist.github.com/dcreager/fc53c59b30d7ce71d478dcb2c1c56444)
of https://github.com/astral-sh/ty/issues/948 is an example of a class
with implicit attributes whose types end up depending on themselves. Our
existing cycle detection for `infer_expression_types` is usually enough
to handle this situation correctly, but when there are very many of
these implicit attributes, we get a combinatorial explosion of running
time and memory usage.

Adding a separate cycle handler for `ClassLiteral::implicit_attribute`
lets us catch and recover from this situation earlier.

Closes https://github.com/astral-sh/ty/issues/948
This commit is contained in:
Douglas Creager 2025-08-08 17:01:17 -04:00 committed by GitHub
parent 4be6fc0979
commit 3a542a80f6
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 41 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
crates/ty_python_semantic/src/types/class.rs
View File

@ -89,6 +89,26 @@ fn inheritance_cycle_initial<'db>(
None
}
fn implicit_attribute_recover<'db>(
_db: &'db dyn Db,
_value: &PlaceAndQualifiers<'db>,
_count: u32,
_class_body_scope: ScopeId<'db>,
_name: String,
_target_method_decorator: MethodDecorator,
) -> salsa::CycleRecoveryAction<PlaceAndQualifiers<'db>> {
salsa::CycleRecoveryAction::Iterate
}
fn implicit_attribute_initial<'db>(
_db: &'db dyn Db,
_class_body_scope: ScopeId<'db>,
_name: String,
_target_method_decorator: MethodDecorator,
) -> PlaceAndQualifiers<'db> {
Place::Unbound.into()
}
fn try_mro_cycle_recover<'db>(
_db: &'db dyn Db,
_value: &Result<Mro<'db>, MroError<'db>>,
@ -2359,6 +2379,25 @@ impl<'db> ClassLiteral<'db> {
class_body_scope: ScopeId<'db>,
name: &str,
target_method_decorator: MethodDecorator,
) -> PlaceAndQualifiers<'db> {
Self::implicit_attribute_inner(
db,
class_body_scope,
name.to_string(),
target_method_decorator,
)
}
#[salsa::tracked(
cycle_fn=implicit_attribute_recover,
cycle_initial=implicit_attribute_initial,
heap_size=ruff_memory_usage::heap_size,
)]
fn implicit_attribute_inner(
db: &'db dyn Db,
class_body_scope: ScopeId<'db>,
name: String,
target_method_decorator: MethodDecorator,
) -> PlaceAndQualifiers<'db> {
// If we do not see any declarations of an attribute, neither in the class body nor in
// any method, we build a union of `Unknown` with the inferred types of all bindings of
@ -2392,7 +2431,7 @@ impl<'db> ClassLiteral<'db> {
// First check declarations
for (attribute_declarations, method_scope_id) in
attribute_declarations(db, class_body_scope, name)
attribute_declarations(db, class_body_scope, &name)
{
let method_scope = method_scope_id.to_scope_id(db, file);
if !is_valid_scope(method_scope) {
@ -2450,7 +2489,7 @@ impl<'db> ClassLiteral<'db> {
}
for (attribute_assignments, method_scope_id) in
attribute_assignments(db, class_body_scope, name)
attribute_assignments(db, class_body_scope, &name)
{
let method_scope = method_scope_id.to_scope_id(db, file);
if !is_valid_scope(method_scope) {