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Raise diagnostic when frozen dataclass inherits a non-frozen dataclass and the other way around

This commit is contained in:
Simon Lamon 2025-12-13 17:49:10 +01:00
parent 82a7598aa8
commit 6368fd0ea5
2 changed files with 103 additions and 29 deletions
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60
crates/ty_python_semantic/src/types/diagnostic.rs
View File

@ -121,6 +121,8 @@ pub(crate) fn register_lints(registry: &mut LintRegistryBuilder) {
registry.register_lint(&INVALID_METHOD_OVERRIDE);
registry.register_lint(&INVALID_EXPLICIT_OVERRIDE);
registry.register_lint(&SUPER_CALL_IN_NAMED_TUPLE_METHOD);
registry.register_lint(&FROZEN_SUBCLASS_OF_NON_FROZEN_DATACLASS);
registry.register_lint(&NON_FROZEN_SUBCLASS_OF_FROZEN_DATACLASS);
// String annotations
registry.register_lint(&BYTE_STRING_TYPE_ANNOTATION);
@ -2220,6 +2222,64 @@ declare_lint! {
}
}
declare_lint! {
/// ## What it does
/// Checks for frozen dataclasses that inherit from non-frozen dataclasses.
///
/// ## Why is this bad?
/// A frozen dataclass promises immutability. Inheriting from a non-frozen
/// dataclass breaks that guarantee because the base class allows mutation.
///
/// ## Example
///
/// ```python
/// from dataclasses import dataclass
///
/// @dataclass
/// class Base:
/// x: int
///
/// @dataclass(frozen=True)
/// class Child(Base): # Error raised here
/// y: int
/// ```
pub(crate) static FROZEN_SUBCLASS_OF_NON_FROZEN_DATACLASS = {
summary: "detects frozen dataclasses inheriting from non-frozen dataclasses",
status: LintStatus::stable("0.0.1-alpha.35"),
default_level: Level::Error,
}
}
declare_lint! {
/// ## What it does
/// Checks for non-frozen dataclasses that inherit from frozen dataclasses.
///
/// ## Why is this bad?
/// A frozen dataclass enforces immutability. Allowing a non-frozen subclass
/// would reintroduce mutability and violate the base class contract.
///
/// ## Example
///
/// ```python
/// from dataclasses import dataclass
///
/// @dataclass(frozen=True)
/// class Base:
/// x: int
///
/// @dataclass
/// class Child(Base): # Error raised here
/// y: int
/// ```
pub(crate) static NON_FROZEN_SUBCLASS_OF_FROZEN_DATACLASS = {
summary: "detects non-frozen dataclasses inheriting from frozen dataclasses",
status: LintStatus::stable("0.0.1-alpha.35"),
default_level: Level::Error,
}
}
/// A collection of type check diagnostics.
#[derive(Default, Eq, PartialEq, get_size2::GetSize)]
pub struct TypeCheckDiagnostics {

72
crates/ty_python_semantic/src/types/infer/builder.rs
View File

@ -55,34 +55,7 @@ use crate::types::call::{Binding, Bindings, CallArguments, CallError, CallErrorK
use crate::types::class::{CodeGeneratorKind, FieldKind, MetaclassErrorKind, MethodDecorator};
use crate::types::context::{InNoTypeCheck, InferContext};
use crate::types::cyclic::CycleDetector;
use crate::types::diagnostic::{
self, CALL_NON_CALLABLE, CONFLICTING_DECLARATIONS, CONFLICTING_METACLASS,
CYCLIC_CLASS_DEFINITION, CYCLIC_TYPE_ALIAS_DEFINITION, DIVISION_BY_ZERO, DUPLICATE_KW_ONLY,
INCONSISTENT_MRO, INVALID_ARGUMENT_TYPE, INVALID_ASSIGNMENT, INVALID_ATTRIBUTE_ACCESS,
INVALID_BASE, INVALID_DECLARATION, INVALID_GENERIC_CLASS, INVALID_KEY,
INVALID_LEGACY_TYPE_VARIABLE, INVALID_METACLASS, INVALID_NAMED_TUPLE, INVALID_NEWTYPE,
INVALID_OVERLOAD, INVALID_PARAMETER_DEFAULT, INVALID_PARAMSPEC, INVALID_PROTOCOL,
INVALID_TYPE_ARGUMENTS, INVALID_TYPE_FORM, INVALID_TYPE_GUARD_CALL,
INVALID_TYPE_VARIABLE_CONSTRAINTS, IncompatibleBases, NON_SUBSCRIPTABLE,
POSSIBLY_MISSING_ATTRIBUTE, POSSIBLY_MISSING_IMPLICIT_CALL, POSSIBLY_MISSING_IMPORT,
SUBCLASS_OF_FINAL_CLASS, UNDEFINED_REVEAL, UNRESOLVED_ATTRIBUTE, UNRESOLVED_GLOBAL,
UNRESOLVED_IMPORT, UNRESOLVED_REFERENCE, UNSUPPORTED_OPERATOR, USELESS_OVERLOAD_BODY,
hint_if_stdlib_attribute_exists_on_other_versions,
hint_if_stdlib_submodule_exists_on_other_versions, report_attempted_protocol_instantiation,
report_bad_dunder_set_call, report_cannot_pop_required_field_on_typed_dict,
report_duplicate_bases, report_implicit_return_type, report_index_out_of_bounds,
report_instance_layout_conflict, report_invalid_arguments_to_annotated,
report_invalid_assignment, report_invalid_attribute_assignment,
report_invalid_exception_caught, report_invalid_exception_cause,
report_invalid_exception_raised, report_invalid_exception_tuple_caught,
report_invalid_generator_function_return_type, report_invalid_key_on_typed_dict,
report_invalid_or_unsupported_base, report_invalid_return_type,
report_invalid_type_checking_constant, report_named_tuple_field_with_leading_underscore,
report_namedtuple_field_without_default_after_field_with_default, report_non_subscriptable,
report_possibly_missing_attribute, report_possibly_unresolved_reference,
report_rebound_typevar, report_slice_step_size_zero, report_unsupported_augmented_assignment,
report_unsupported_binary_operation, report_unsupported_comparison,
};
use crate::types::diagnostic::{self, CALL_NON_CALLABLE, CONFLICTING_DECLARATIONS, CONFLICTING_METACLASS, CYCLIC_CLASS_DEFINITION, CYCLIC_TYPE_ALIAS_DEFINITION, DIVISION_BY_ZERO, DUPLICATE_KW_ONLY, INCONSISTENT_MRO, INVALID_ARGUMENT_TYPE, INVALID_ASSIGNMENT, INVALID_ATTRIBUTE_ACCESS, INVALID_BASE, INVALID_DECLARATION, INVALID_GENERIC_CLASS, INVALID_KEY, INVALID_LEGACY_TYPE_VARIABLE, INVALID_METACLASS, INVALID_NAMED_TUPLE, INVALID_NEWTYPE, INVALID_OVERLOAD, INVALID_PARAMETER_DEFAULT, INVALID_PARAMSPEC, INVALID_PROTOCOL, INVALID_TYPE_ARGUMENTS, INVALID_TYPE_FORM, INVALID_TYPE_GUARD_CALL, INVALID_TYPE_VARIABLE_CONSTRAINTS, IncompatibleBases, NON_SUBSCRIPTABLE, POSSIBLY_MISSING_ATTRIBUTE, POSSIBLY_MISSING_IMPLICIT_CALL, POSSIBLY_MISSING_IMPORT, SUBCLASS_OF_FINAL_CLASS, UNDEFINED_REVEAL, UNRESOLVED_ATTRIBUTE, UNRESOLVED_GLOBAL, UNRESOLVED_IMPORT, UNRESOLVED_REFERENCE, UNSUPPORTED_OPERATOR, USELESS_OVERLOAD_BODY, hint_if_stdlib_attribute_exists_on_other_versions, hint_if_stdlib_submodule_exists_on_other_versions, report_attempted_protocol_instantiation, report_bad_dunder_set_call, report_cannot_pop_required_field_on_typed_dict, report_duplicate_bases, report_implicit_return_type, report_index_out_of_bounds, report_instance_layout_conflict, report_invalid_arguments_to_annotated, report_invalid_assignment, report_invalid_attribute_assignment, report_invalid_exception_caught, report_invalid_exception_cause, report_invalid_exception_raised, report_invalid_exception_tuple_caught, report_invalid_generator_function_return_type, report_invalid_key_on_typed_dict, report_invalid_or_unsupported_base, report_invalid_return_type, report_invalid_type_checking_constant, report_named_tuple_field_with_leading_underscore, report_namedtuple_field_without_default_after_field_with_default, report_non_subscriptable, report_possibly_missing_attribute, report_possibly_unresolved_reference, report_rebound_typevar, report_slice_step_size_zero, report_unsupported_augmented_assignment, report_unsupported_binary_operation, report_unsupported_comparison, FROZEN_SUBCLASS_OF_NON_FROZEN_DATACLASS, NON_FROZEN_SUBCLASS_OF_FROZEN_DATACLASS};
use crate::types::function::{
FunctionDecorators, FunctionLiteral, FunctionType, KnownFunction, OverloadLiteral,
is_implicit_classmethod, is_implicit_staticmethod,
@ -104,7 +77,7 @@ use crate::types::typed_dict::{
use crate::types::visitor::any_over_type;
use crate::types::{
BoundTypeVarInstance, CallDunderError, CallableBinding, CallableType, CallableTypeKind,
ClassLiteral, ClassType, DataclassParams, DynamicType, InternedType, IntersectionBuilder,
ClassLiteral, ClassType, DataclassFlags, DataclassParams, DynamicType, InternedType, IntersectionBuilder,
IntersectionType, KnownClass, KnownInstanceType, KnownUnion, LintDiagnosticGuard,
MemberLookupPolicy, MetaclassCandidate, PEP695TypeAliasType, ParamSpecAttrKind, Parameter,
ParameterForm, Parameters, Signature, SpecialFormType, SubclassOfType, TrackedConstraintSet,
@ -755,6 +728,47 @@ impl<'db, 'ast> TypeInferenceBuilder<'db, 'ast> {
));
}
}
let (base_class_literal, _) = base_class.class_literal(self.db());
if let (Some(base_params), Some(class_params)) = (
base_class_literal.dataclass_params(self.db()),
class.dataclass_params(self.db()),
) {
let base_is_frozen = base_params.flags(self.db())
.contains(DataclassFlags::FROZEN);
let class_is_frozen = class_params.flags(self.db())
.contains(DataclassFlags::FROZEN);
match (base_is_frozen, class_is_frozen) {
(true, false) => {
if let Some(builder) = self.context.report_lint(
&NON_FROZEN_SUBCLASS_OF_FROZEN_DATACLASS,
&class_node.bases()[i],
) {
builder.into_diagnostic(format_args!(
"A non-frozen class `{}` cannot inherit from a class `{}` that is frozen",
class.name(self.db()),
base_class.name(self.db()),
));
}
}
(false, true) => {
if let Some(builder) = self.context.report_lint(
&FROZEN_SUBCLASS_OF_NON_FROZEN_DATACLASS,
&class_node.bases()[i],
) {
builder.into_diagnostic(format_args!(
"A frozen class `{}` cannot inherit from a class `{}` that is not frozen",
class.name(self.db()),
base_class.name(self.db()),
));
}
}
_ => {}
}
}
}
// (4) Check that the class's MRO is resolvable