diff --git a/crates/ty/docs/rules.md b/crates/ty/docs/rules.md
index e32e8d3e53..c2b450ae10 100644
--- a/crates/ty/docs/rules.md
+++ b/crates/ty/docs/rules.md
@@ -39,7 +39,7 @@ def test(): -> "int":
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@@ -63,7 +63,7 @@ Calling a non-callable object will raise a `TypeError` at runtime.
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@@ -95,7 +95,7 @@ f(int) # error
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@@ -126,7 +126,7 @@ a = 1
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@@ -357,7 +357,7 @@ def test(): -> "Literal[5]":
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@@ -387,7 +387,7 @@ class C(A, B): ...
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@@ -413,7 +413,7 @@ t[3] # IndexError: tuple index out of range
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@@ -502,7 +502,7 @@ an atypical memory layout.
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@@ -529,7 +529,7 @@ func("foo") # error: [invalid-argument-type]
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@@ -557,7 +557,7 @@ a: int = ''
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@@ -591,7 +591,7 @@ C.instance_var = 3 # error: Cannot assign to instance variable
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@@ -627,7 +627,7 @@ asyncio.run(main())
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@@ -651,7 +651,7 @@ class A(42): ... # error: [invalid-base]
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@@ -678,7 +678,7 @@ with 1:
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@@ -707,7 +707,7 @@ a: str
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@@ -751,7 +751,7 @@ except ZeroDivisionError:
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@@ -787,13 +787,57 @@ class D(A):
def foo(self): ... # fine: overrides `A.foo`
```
+## `invalid-frozen-dataclass-subclass`
+
+
+Default level: error ·
+Added in 0.0.1-alpha.35 ·
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+
+
+
+**What it does**
+
+Checks for dataclasses with invalid frozen inheritance:
+- A frozen dataclass cannot inherit from a non-frozen dataclass.
+- A non-frozen dataclass cannot inherit from a frozen dataclass.
+
+**Why is this bad?**
+
+Python raises a `TypeError` at runtime when either of these inheritance
+patterns occurs.
+
+**Example**
+
+
+```python
+from dataclasses import dataclass
+
+@dataclass
+class Base:
+ x: int
+
+@dataclass(frozen=True)
+class Child(Base): # Error raised here
+ y: int
+
+@dataclass(frozen=True)
+class FrozenBase:
+ x: int
+
+@dataclass
+class NonFrozenChild(FrozenBase): # Error raised here
+ y: int
+```
+
## `invalid-generic-class`
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@@ -826,7 +870,7 @@ class C[U](Generic[T]): ...
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@@ -865,7 +909,7 @@ carol = Person(name="Carol", age=25) # typo!
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@@ -900,7 +944,7 @@ def f(t: TypeVar("U")): ...
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@@ -934,7 +978,7 @@ class B(metaclass=f): ...
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@@ -1041,7 +1085,7 @@ Correct use of `@override` is enforced by ty's `invalid-explicit-override` rule.
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@@ -1095,7 +1139,7 @@ AttributeError: Cannot overwrite NamedTuple attribute _asdict
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@@ -1125,7 +1169,7 @@ Baz = NewType("Baz", int | str) # error: invalid base for `typing.NewType`
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@@ -1175,7 +1219,7 @@ def foo(x: int) -> int: ...
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@@ -1201,7 +1245,7 @@ def f(a: int = ''): ...
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@@ -1232,7 +1276,7 @@ P2 = ParamSpec("S2") # error: ParamSpec name must match the variable it's assig
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@@ -1266,7 +1310,7 @@ TypeError: Protocols can only inherit from other protocols, got
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@@ -1315,7 +1359,7 @@ def g():
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@@ -1340,7 +1384,7 @@ def func() -> int:
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@@ -1398,7 +1442,7 @@ TODO #14889
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@@ -1425,7 +1469,7 @@ NewAlias = TypeAliasType(get_name(), int) # error: TypeAliasType name mus
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@@ -1472,7 +1516,7 @@ Bar[int] # error: too few arguments
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@@ -1502,7 +1546,7 @@ TYPE_CHECKING = ''
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@@ -1532,7 +1576,7 @@ b: Annotated[int] # `Annotated` expects at least two arguments
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@@ -1566,7 +1610,7 @@ f(10) # Error
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@@ -1600,7 +1644,7 @@ class C:
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@@ -1635,7 +1679,7 @@ T = TypeVar('T', bound=str) # valid bound TypeVar
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@@ -1660,7 +1704,7 @@ func() # TypeError: func() missing 1 required positional argument: 'x'
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@@ -1693,7 +1737,7 @@ alice["age"] # KeyError
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@@ -1722,7 +1766,7 @@ func("string") # error: [no-matching-overload]
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@@ -1746,7 +1790,7 @@ Subscripting an object that does not support it will raise a `TypeError` at runt
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@@ -1772,7 +1816,7 @@ for i in 34: # TypeError: 'int' object is not iterable
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@@ -1805,7 +1849,7 @@ class B(A):
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@@ -1832,7 +1876,7 @@ f(1, x=2) # Error raised here
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@@ -1890,7 +1934,7 @@ def test(): -> "int":
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@@ -1920,7 +1964,7 @@ static_assert(int(2.0 * 3.0) == 6) # error: does not have a statically known tr
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@@ -1949,7 +1993,7 @@ class B(A): ... # Error raised here
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@@ -1983,7 +2027,7 @@ class F(NamedTuple):
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@@ -2010,7 +2054,7 @@ f("foo") # Error raised here
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@@ -2038,7 +2082,7 @@ def _(x: int):
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@@ -2084,7 +2128,7 @@ class A:
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@@ -2111,7 +2155,7 @@ f(x=1, y=2) # Error raised here
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@@ -2139,7 +2183,7 @@ A().foo # AttributeError: 'A' object has no attribute 'foo'
Default level: error ·
Added in 0.0.1-alpha.1 ·
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@@ -2164,7 +2208,7 @@ import foo # ModuleNotFoundError: No module named 'foo'
Default level: error ·
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@@ -2189,7 +2233,7 @@ print(x) # NameError: name 'x' is not defined
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Added in 0.0.1-alpha.1 ·
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@@ -2226,7 +2270,7 @@ b1 < b2 < b1 # exception raised here
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@@ -2254,7 +2298,7 @@ A() + A() # TypeError: unsupported operand type(s) for +: 'A' and 'A'
Default level: error ·
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@@ -2279,7 +2323,7 @@ l[1:10:0] # ValueError: slice step cannot be zero
Default level: warn ·
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@@ -2320,7 +2364,7 @@ class SubProto(BaseProto, Protocol):
Default level: warn ·
Added in 0.0.1-alpha.16 ·
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@@ -2408,7 +2452,7 @@ a = 20 / 0 # type: ignore
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Added in 0.0.1-alpha.22 ·
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@@ -2436,7 +2480,7 @@ A.c # AttributeError: type object 'A' has no attribute 'c'
Default level: warn ·
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@@ -2468,7 +2512,7 @@ A()[0] # TypeError: 'A' object is not subscriptable
Default level: warn ·
Added in 0.0.1-alpha.22 ·
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@@ -2500,7 +2544,7 @@ from module import a # ImportError: cannot import name 'a' from 'module'
Default level: warn ·
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@@ -2527,7 +2571,7 @@ cast(int, f()) # Redundant
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@@ -2551,7 +2595,7 @@ reveal_type(1) # NameError: name 'reveal_type' is not defined
Default level: warn ·
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@@ -2609,7 +2653,7 @@ def g():
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@@ -2648,7 +2692,7 @@ class D(C): ... # error: [unsupported-base]
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@@ -2711,7 +2755,7 @@ def foo(x: int | str) -> int | str:
Default level: ignore ·
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@@ -2735,7 +2779,7 @@ Dividing by zero raises a `ZeroDivisionError` at runtime.
Default level: ignore ·
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diff --git a/crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md b/crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md
index 7c64175658..60bfd36176 100644
--- a/crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md
+++ b/crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md
@@ -521,6 +521,73 @@ frozen = MyFrozenChildClass()
del frozen.x # TODO this should emit an [invalid-assignment]
```
+### frozen/non-frozen inheritance
+
+If a non-frozen dataclass inherits from a frozen dataclass, an exception is raised at runtime. We
+catch this error:
+
+
+
+`a.py`:
+
+```py
+from dataclasses import dataclass
+
+@dataclass(frozen=True)
+class FrozenBase:
+ x: int
+
+@dataclass
+# error: [invalid-frozen-dataclass-subclass] "Non-frozen dataclass `Child` cannot inherit from frozen dataclass `FrozenBase`"
+class Child(FrozenBase):
+ y: int
+```
+
+Frozen dataclasses inheriting from non-frozen dataclasses are also illegal:
+
+`b.py`:
+
+```py
+from dataclasses import dataclass
+
+@dataclass
+class Base:
+ x: int
+
+@dataclass(frozen=True)
+# error: [invalid-frozen-dataclass-subclass] "Frozen dataclass `FrozenChild` cannot inherit from non-frozen dataclass `Base`"
+class FrozenChild(Base):
+ y: int
+```
+
+Example of diagnostics when there are multiple files involved:
+
+`module.py`:
+
+```py
+import dataclasses
+
+@dataclasses.dataclass(frozen=False)
+class NotFrozenBase:
+ x: int
+```
+
+`main.py`:
+
+```py
+from functools import total_ordering
+from typing import final
+from dataclasses import dataclass
+
+from module import NotFrozenBase
+
+@final
+@dataclass(frozen=True)
+@total_ordering
+class FrozenChild(NotFrozenBase): # error: [invalid-frozen-dataclass-subclass]
+ y: str
+```
+
### `match_args`
If `match_args` is set to `True` (the default), the `__match_args__` attribute is a tuple created
diff --git a/crates/ty_python_semantic/resources/mdtest/snapshots/dataclasses.md_-_Dataclasses_-_Other_dataclass_para…_-_frozen__non-frozen_in…_(9af2ab07b8e829e).snap b/crates/ty_python_semantic/resources/mdtest/snapshots/dataclasses.md_-_Dataclasses_-_Other_dataclass_para…_-_frozen__non-frozen_in…_(9af2ab07b8e829e).snap
new file mode 100644
index 0000000000..3b3a006b6e
--- /dev/null
+++ b/crates/ty_python_semantic/resources/mdtest/snapshots/dataclasses.md_-_Dataclasses_-_Other_dataclass_para…_-_frozen__non-frozen_in…_(9af2ab07b8e829e).snap
@@ -0,0 +1,154 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: dataclasses.md - Dataclasses - Other dataclass parameters - frozen/non-frozen inheritance
+mdtest path: crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md
+---
+
+# Python source files
+
+## a.py
+
+```
+ 1 | from dataclasses import dataclass
+ 2 |
+ 3 | @dataclass(frozen=True)
+ 4 | class FrozenBase:
+ 5 | x: int
+ 6 |
+ 7 | @dataclass
+ 8 | # error: [invalid-frozen-dataclass-subclass] "Non-frozen dataclass `Child` cannot inherit from frozen dataclass `FrozenBase`"
+ 9 | class Child(FrozenBase):
+10 | y: int
+```
+
+## b.py
+
+```
+ 1 | from dataclasses import dataclass
+ 2 |
+ 3 | @dataclass
+ 4 | class Base:
+ 5 | x: int
+ 6 |
+ 7 | @dataclass(frozen=True)
+ 8 | # error: [invalid-frozen-dataclass-subclass] "Frozen dataclass `FrozenChild` cannot inherit from non-frozen dataclass `Base`"
+ 9 | class FrozenChild(Base):
+10 | y: int
+```
+
+## module.py
+
+```
+1 | import dataclasses
+2 |
+3 | @dataclasses.dataclass(frozen=False)
+4 | class NotFrozenBase:
+5 | x: int
+```
+
+## main.py
+
+```
+ 1 | from functools import total_ordering
+ 2 | from typing import final
+ 3 | from dataclasses import dataclass
+ 4 |
+ 5 | from module import NotFrozenBase
+ 6 |
+ 7 | @final
+ 8 | @dataclass(frozen=True)
+ 9 | @total_ordering
+10 | class FrozenChild(NotFrozenBase): # error: [invalid-frozen-dataclass-subclass]
+11 | y: str
+```
+
+# Diagnostics
+
+```
+error[invalid-frozen-dataclass-subclass]: Non-frozen dataclass cannot inherit from frozen dataclass
+ --> src/a.py:7:1
+ |
+ 5 | x: int
+ 6 |
+ 7 | @dataclass
+ | ---------- `Child` dataclass parameters
+ 8 | # error: [invalid-frozen-dataclass-subclass] "Non-frozen dataclass `Child` cannot inherit from frozen dataclass `FrozenBase`"
+ 9 | class Child(FrozenBase):
+ | ^^^^^^----------^ Subclass `Child` is not frozen but base class `FrozenBase` is
+10 | y: int
+ |
+info: This causes the class creation to fail
+info: Base class definition
+ --> src/a.py:3:1
+ |
+1 | from dataclasses import dataclass
+2 |
+3 | @dataclass(frozen=True)
+ | ----------------------- `FrozenBase` dataclass parameters
+4 | class FrozenBase:
+ | ^^^^^^^^^^ `FrozenBase` definition
+5 | x: int
+ |
+info: rule `invalid-frozen-dataclass-subclass` is enabled by default
+
+```
+
+```
+error[invalid-frozen-dataclass-subclass]: Frozen dataclass cannot inherit from non-frozen dataclass
+ --> src/b.py:7:1
+ |
+ 5 | x: int
+ 6 |
+ 7 | @dataclass(frozen=True)
+ | ----------------------- `FrozenChild` dataclass parameters
+ 8 | # error: [invalid-frozen-dataclass-subclass] "Frozen dataclass `FrozenChild` cannot inherit from non-frozen dataclass `Base`"
+ 9 | class FrozenChild(Base):
+ | ^^^^^^^^^^^^----^ Subclass `FrozenChild` is frozen but base class `Base` is not
+10 | y: int
+ |
+info: This causes the class creation to fail
+info: Base class definition
+ --> src/b.py:3:1
+ |
+1 | from dataclasses import dataclass
+2 |
+3 | @dataclass
+ | ---------- `Base` dataclass parameters
+4 | class Base:
+ | ^^^^ `Base` definition
+5 | x: int
+ |
+info: rule `invalid-frozen-dataclass-subclass` is enabled by default
+
+```
+
+```
+error[invalid-frozen-dataclass-subclass]: Frozen dataclass cannot inherit from non-frozen dataclass
+ --> src/main.py:8:1
+ |
+ 7 | @final
+ 8 | @dataclass(frozen=True)
+ | ----------------------- `FrozenChild` dataclass parameters
+ 9 | @total_ordering
+10 | class FrozenChild(NotFrozenBase): # error: [invalid-frozen-dataclass-subclass]
+ | ^^^^^^^^^^^^-------------^ Subclass `FrozenChild` is frozen but base class `NotFrozenBase` is not
+11 | y: str
+ |
+info: This causes the class creation to fail
+info: Base class definition
+ --> src/module.py:3:1
+ |
+1 | import dataclasses
+2 |
+3 | @dataclasses.dataclass(frozen=False)
+ | ------------------------------------ `NotFrozenBase` dataclass parameters
+4 | class NotFrozenBase:
+ | ^^^^^^^^^^^^^ `NotFrozenBase` definition
+5 | x: int
+ |
+info: rule `invalid-frozen-dataclass-subclass` is enabled by default
+
+```
diff --git a/crates/ty_python_semantic/src/types.rs b/crates/ty_python_semantic/src/types.rs
index e9311547d7..726decfc07 100644
--- a/crates/ty_python_semantic/src/types.rs
+++ b/crates/ty_python_semantic/src/types.rs
@@ -677,6 +677,12 @@ bitflags! {
}
}
+impl DataclassFlags {
+ pub(crate) const fn is_frozen(self) -> bool {
+ self.contains(Self::FROZEN)
+ }
+}
+
pub(crate) const DATACLASS_FLAGS: &[(&str, DataclassFlags)] = &[
("init", DataclassFlags::INIT),
("repr", DataclassFlags::REPR),
diff --git a/crates/ty_python_semantic/src/types/class.rs b/crates/ty_python_semantic/src/types/class.rs
index 32962ea128..022e63fe33 100644
--- a/crates/ty_python_semantic/src/types/class.rs
+++ b/crates/ty_python_semantic/src/types/class.rs
@@ -1856,6 +1856,28 @@ impl<'db> ClassLiteral<'db> {
.filter_map(|decorator| decorator.known(db))
}
+ /// Iterate through the decorators on this class, returning the position of the first one
+ /// that matches the given predicate.
+ pub(super) fn find_decorator_position(
+ self,
+ db: &'db dyn Db,
+ predicate: impl Fn(Type<'db>) -> bool,
+ ) -> Option {
+ self.decorators(db)
+ .iter()
+ .position(|decorator| predicate(*decorator))
+ }
+
+ /// Iterate through the decorators on this class, returning the index of the first one
+ /// that is either `@dataclass` or `@dataclass(...)`.
+ pub(super) fn find_dataclass_decorator_position(self, db: &'db dyn Db) -> Option {
+ self.find_decorator_position(db, |ty| match ty {
+ Type::FunctionLiteral(function) => function.is_known(db, KnownFunction::Dataclass),
+ Type::DataclassDecorator(_) => true,
+ _ => false,
+ })
+ }
+
/// Is this class final?
pub(super) fn is_final(self, db: &'db dyn Db) -> bool {
self.known_function_decorators(db)
diff --git a/crates/ty_python_semantic/src/types/diagnostic.rs b/crates/ty_python_semantic/src/types/diagnostic.rs
index dcc2f6b3c5..3acd7b0a64 100644
--- a/crates/ty_python_semantic/src/types/diagnostic.rs
+++ b/crates/ty_python_semantic/src/types/diagnostic.rs
@@ -30,7 +30,7 @@ use crate::types::{
ProtocolInstanceType, SpecialFormType, SubclassOfInner, Type, TypeContext, binding_type,
protocol_class::ProtocolClass,
};
-use crate::types::{KnownInstanceType, MemberLookupPolicy};
+use crate::types::{DataclassFlags, KnownInstanceType, MemberLookupPolicy};
use crate::{Db, DisplaySettings, FxIndexMap, Module, ModuleName, Program, declare_lint};
use itertools::Itertools;
use ruff_db::{
@@ -121,6 +121,7 @@ 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(&INVALID_FROZEN_DATACLASS_SUBCLASS);
// String annotations
registry.register_lint(&BYTE_STRING_TYPE_ANNOTATION);
@@ -2220,6 +2221,44 @@ declare_lint! {
}
}
+declare_lint! {
+ /// ## What it does
+ /// Checks for dataclasses with invalid frozen inheritance:
+ /// - A frozen dataclass cannot inherit from a non-frozen dataclass.
+ /// - A non-frozen dataclass cannot inherit from a frozen dataclass.
+ ///
+ /// ## Why is this bad?
+ /// Python raises a `TypeError` at runtime when either of these inheritance
+ /// patterns occurs.
+ ///
+ /// ## Example
+ ///
+ /// ```python
+ /// from dataclasses import dataclass
+ ///
+ /// @dataclass
+ /// class Base:
+ /// x: int
+ ///
+ /// @dataclass(frozen=True)
+ /// class Child(Base): # Error raised here
+ /// y: int
+ ///
+ /// @dataclass(frozen=True)
+ /// class FrozenBase:
+ /// x: int
+ ///
+ /// @dataclass
+ /// class NonFrozenChild(FrozenBase): # Error raised here
+ /// y: int
+ /// ```
+ pub(crate) static INVALID_FROZEN_DATACLASS_SUBCLASS = {
+ summary: "detects dataclasses with invalid frozen/non-frozen subclassing",
+ 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 {
@@ -4269,6 +4308,94 @@ fn report_unsupported_binary_operation_impl<'a>(
Some(diagnostic)
}
+pub(super) fn report_bad_frozen_dataclass_inheritance<'db>(
+ context: &InferContext<'db, '_>,
+ class: ClassLiteral<'db>,
+ class_node: &ast::StmtClassDef,
+ base_class: ClassLiteral<'db>,
+ base_class_node: &ast::Expr,
+ base_class_params: DataclassFlags,
+) {
+ let db = context.db();
+
+ let Some(builder) =
+ context.report_lint(&INVALID_FROZEN_DATACLASS_SUBCLASS, class.header_range(db))
+ else {
+ return;
+ };
+
+ let mut diagnostic = if base_class_params.is_frozen() {
+ let mut diagnostic =
+ builder.into_diagnostic("Non-frozen dataclass cannot inherit from frozen dataclass");
+ diagnostic.set_concise_message(format_args!(
+ "Non-frozen dataclass `{}` cannot inherit from frozen dataclass `{}`",
+ class.name(db),
+ base_class.name(db)
+ ));
+ diagnostic.set_primary_message(format_args!(
+ "Subclass `{}` is not frozen but base class `{}` is",
+ class.name(db),
+ base_class.name(db)
+ ));
+ diagnostic
+ } else {
+ let mut diagnostic =
+ builder.into_diagnostic("Frozen dataclass cannot inherit from non-frozen dataclass");
+ diagnostic.set_concise_message(format_args!(
+ "Frozen dataclass `{}` cannot inherit from non-frozen dataclass `{}`",
+ class.name(db),
+ base_class.name(db)
+ ));
+ diagnostic.set_primary_message(format_args!(
+ "Subclass `{}` is frozen but base class `{}` is not",
+ class.name(db),
+ base_class.name(db)
+ ));
+ diagnostic
+ };
+
+ diagnostic.annotate(context.secondary(base_class_node));
+
+ if let Some(position) = class.find_dataclass_decorator_position(db) {
+ diagnostic.annotate(
+ context
+ .secondary(&class_node.decorator_list[position])
+ .message(format_args!("`{}` dataclass parameters", class.name(db))),
+ );
+ }
+ diagnostic.info("This causes the class creation to fail");
+
+ if let Some(decorator_position) = base_class.find_dataclass_decorator_position(db) {
+ let mut sub = SubDiagnostic::new(
+ SubDiagnosticSeverity::Info,
+ format_args!("Base class definition"),
+ );
+ sub.annotate(
+ Annotation::primary(base_class.header_span(db))
+ .message(format_args!("`{}` definition", base_class.name(db))),
+ );
+
+ let base_class_file = base_class.file(db);
+ let module = parsed_module(db, base_class_file).load(db);
+
+ let decorator_range = base_class
+ .body_scope(db)
+ .node(db)
+ .expect_class()
+ .node(&module)
+ .decorator_list[decorator_position]
+ .range();
+
+ sub.annotate(
+ Annotation::secondary(Span::from(base_class_file).with_range(decorator_range)).message(
+ format_args!("`{}` dataclass parameters", base_class.name(db)),
+ ),
+ );
+
+ diagnostic.sub(sub);
+ }
+}
+
/// This function receives an unresolved `from foo import bar` import,
/// where `foo` can be resolved to a module but that module does not
/// have a `bar` member or submodule.
diff --git a/crates/ty_python_semantic/src/types/infer/builder.rs b/crates/ty_python_semantic/src/types/infer/builder.rs
index 1b78a02c32..43940a4d88 100644
--- a/crates/ty_python_semantic/src/types/infer/builder.rs
+++ b/crates/ty_python_semantic/src/types/infer/builder.rs
@@ -69,15 +69,16 @@ use crate::types::diagnostic::{
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_bad_dunder_set_call, report_bad_frozen_dataclass_inheritance,
+ 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,
@@ -755,6 +756,27 @@ 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_params = base_params.flags(self.db());
+ let class_is_frozen = class_params.flags(self.db()).is_frozen();
+
+ if base_params.is_frozen() != class_is_frozen {
+ report_bad_frozen_dataclass_inheritance(
+ &self.context,
+ class,
+ class_node,
+ base_class_literal,
+ &class_node.bases()[i],
+ base_params,
+ );
+ }
+ }
}
// (4) Check that the class's MRO is resolvable
diff --git a/crates/ty_server/tests/e2e/snapshots/e2e__commands__debug_command.snap b/crates/ty_server/tests/e2e/snapshots/e2e__commands__debug_command.snap
index 21c4b05014..cf1b0afc64 100644
--- a/crates/ty_server/tests/e2e/snapshots/e2e__commands__debug_command.snap
+++ b/crates/ty_server/tests/e2e/snapshots/e2e__commands__debug_command.snap
@@ -55,6 +55,7 @@ Settings: Settings {
"invalid-declaration": Error (Default),
"invalid-exception-caught": Error (Default),
"invalid-explicit-override": Error (Default),
+ "invalid-frozen-dataclass-subclass": Error (Default),
"invalid-generic-class": Error (Default),
"invalid-ignore-comment": Warning (Default),
"invalid-key": Error (Default),
diff --git a/ty.schema.json b/ty.schema.json
index 13d1ac9c47..87feeb2507 100644
--- a/ty.schema.json
+++ b/ty.schema.json
@@ -583,6 +583,16 @@
}
]
},
+ "invalid-frozen-dataclass-subclass": {
+ "title": "detects dataclasses with invalid frozen/non-frozen subclassing",
+ "description": "## What it does\nChecks for dataclasses with invalid frozen inheritance:\n- A frozen dataclass cannot inherit from a non-frozen dataclass.\n- A non-frozen dataclass cannot inherit from a frozen dataclass.\n\n## Why is this bad?\nPython raises a `TypeError` at runtime when either of these inheritance\npatterns occurs.\n\n## Example\n\n```python\nfrom dataclasses import dataclass\n\n@dataclass\nclass Base:\n x: int\n\n@dataclass(frozen=True)\nclass Child(Base): # Error raised here\n y: int\n\n@dataclass(frozen=True)\nclass FrozenBase:\n x: int\n\n@dataclass\nclass NonFrozenChild(FrozenBase): # Error raised here\n y: int\n```",
+ "default": "error",
+ "oneOf": [
+ {
+ "$ref": "#/definitions/Level"
+ }
+ ]
+ },
"invalid-generic-class": {
"title": "detects invalid generic classes",
"description": "## What it does\nChecks for the creation of invalid generic classes\n\n## Why is this bad?\nThere are several requirements that you must follow when defining a generic class.\n\n## Examples\n```python\nfrom typing import Generic, TypeVar\n\nT = TypeVar(\"T\") # okay\n\n# error: class uses both PEP-695 syntax and legacy syntax\nclass C[U](Generic[T]): ...\n```\n\n## References\n- [Typing spec: Generics](https://typing.python.org/en/latest/spec/generics.html#introduction)",