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youknowone merged 3 commits into from
Jun 30, 2025
Merged

Iterable for PyGenericAlias #5876

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f016716
Iterable for PyGenericAlias
youknowone Jun 30, 2025
685e413
GenericAlias works
youknowone Jun 30, 2025
021b8eb
typevar.rs
youknowone Jun 30, 2025
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35 changes: 5 additions & 30 deletions Lib/test/test_typing.py
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Original file line number Diff line number Diff line change
Expand Up @@ -680,8 +680,6 @@ def test_typevartuple(self):
class A(Generic[Unpack[Ts]]): ...
Alias = Optional[Unpack[Ts]]

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_typevartuple_specialization(self):
T = TypeVar("T")
Ts = TypeVarTuple('Ts', default=Unpack[Tuple[str, int]])
Expand All @@ -691,8 +689,6 @@ class A(Generic[T, Unpack[Ts]]): ...
self.assertEqual(A[float, range].__args__, (float, range))
self.assertEqual(A[float, *tuple[int, ...]].__args__, (float, *tuple[int, ...]))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_typevar_and_typevartuple_specialization(self):
T = TypeVar("T")
U = TypeVar("U", default=float)
Expand Down Expand Up @@ -740,8 +736,6 @@ class A(Generic[T, P]): ...
self.assertEqual(A[float].__args__, (float, (str, int)))
self.assertEqual(A[float, [range]].__args__, (float, (range,)))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_typevar_and_paramspec_specialization(self):
T = TypeVar("T")
U = TypeVar("U", default=float)
Expand All @@ -752,8 +746,6 @@ class A(Generic[T, U, P]): ...
self.assertEqual(A[float, int].__args__, (float, int, (str, int)))
self.assertEqual(A[float, int, [range]].__args__, (float, int, (range,)))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_paramspec_and_typevar_specialization(self):
T = TypeVar("T")
P = ParamSpec('P', default=[str, int])
Expand Down Expand Up @@ -1049,8 +1041,6 @@ class C(Generic[T1, T2]): pass
eval(expected_str)
)

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_three_parameters(self):
T1 = TypeVar('T1')
T2 = TypeVar('T2')
Expand Down Expand Up @@ -2543,8 +2533,6 @@ def __call__(self):
self.assertIs(a().__class__, C1)
self.assertEqual(a().__orig_class__, C1[[int], T])

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_paramspec(self):
Callable = self.Callable
fullname = f"{Callable.__module__}.Callable"
Expand Down Expand Up @@ -2579,8 +2567,6 @@ def test_paramspec(self):
self.assertEqual(repr(C2), f"{fullname}[~P, int]")
self.assertEqual(repr(C2[int, str]), f"{fullname}[[int, str], int]")

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_concatenate(self):
Callable = self.Callable
fullname = f"{Callable.__module__}.Callable"
Expand Down Expand Up @@ -2608,8 +2594,6 @@ def test_concatenate(self):
Callable[Concatenate[int, str, P2], int])
self.assertEqual(C[...], Callable[Concatenate[int, ...], int])

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_nested_paramspec(self):
# Since Callable has some special treatment, we want to be sure
# that substituion works correctly, see gh-103054
Expand Down Expand Up @@ -2652,8 +2636,6 @@ class My(Generic[P, T]):
self.assertEqual(C4[bool, bytes, float],
My[[Callable[[int, bool, bytes, str], float], float], float])

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_errors(self):
Callable = self.Callable
alias = Callable[[int, str], float]
Expand Down Expand Up @@ -2682,6 +2664,11 @@ def test_consistency(self):
class CollectionsCallableTests(BaseCallableTests, BaseTestCase):
Callable = collections.abc.Callable

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_errors(self):
super().test_errors()


class LiteralTests(BaseTestCase):
def test_basics(self):
Expand Down Expand Up @@ -4631,8 +4618,6 @@ class Base(Generic[T_co]):
class Sub(Base, Generic[T]):
...

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_parameter_detection(self):
self.assertEqual(List[T].__parameters__, (T,))
self.assertEqual(List[List[T]].__parameters__, (T,))
Expand All @@ -4650,8 +4635,6 @@ class A:
# C version of GenericAlias
self.assertEqual(list[A()].__parameters__, (T,))

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_non_generic_subscript(self):
T = TypeVar('T')
class G(Generic[T]):
Expand Down Expand Up @@ -8858,8 +8841,6 @@ def test_bad_var_substitution(self):
with self.assertRaises(TypeError):
collections.abc.Callable[P, T][arg, str]

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_type_var_subst_for_other_type_vars(self):
T = TypeVar('T')
T2 = TypeVar('T2')
Expand Down Expand Up @@ -8981,8 +8962,6 @@ class PandT(Generic[P, T]):
self.assertEqual(C3.__args__, ((int, *Ts), T))
self.assertEqual(C3[str, bool, bytes], PandT[[int, str, bool], bytes])

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_paramspec_in_nested_generics(self):
# Although ParamSpec should not be found in __parameters__ of most
# generics, they probably should be found when nested in
Expand All @@ -9001,8 +8980,6 @@ def test_paramspec_in_nested_generics(self):
self.assertEqual(G2[[int, str], float], list[C])
self.assertEqual(G3[[int, str], float], list[C] | int)

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_paramspec_gets_copied(self):
# bpo-46581
P = ParamSpec('P')
Expand Down Expand Up @@ -9090,8 +9067,6 @@ def test_invalid_uses(self):
):
Concatenate[int]

# TODO: RUSTPYTHON
@unittest.expectedFailure
def test_var_substitution(self):
T = TypeVar('T')
P = ParamSpec('P')
Expand Down
145 changes: 113 additions & 32 deletions vm/src/builtins/genericalias.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,8 +12,8 @@ use crate::{
function::{FuncArgs, PyComparisonValue},
protocol::{PyMappingMethods, PyNumberMethods},
types::{
AsMapping, AsNumber, Callable, Comparable, Constructor, GetAttr, Hashable, PyComparisonOp,
Representable,
AsMapping, AsNumber, Callable, Comparable, Constructor, GetAttr, Hashable, Iterable,
PyComparisonOp, Representable,
},
};
use std::fmt;
Expand Down Expand Up @@ -78,6 +78,7 @@ impl Constructor for PyGenericAlias {
Constructor,
GetAttr,
Hashable,
Iterable,
Representable
),
flags(BASETYPE)
Expand Down Expand Up @@ -166,17 +167,17 @@ impl PyGenericAlias {
}

#[pymethod]
fn __getitem__(&self, needle: PyObjectRef, vm: &VirtualMachine) -> PyResult {
fn __getitem__(zelf: PyRef<Self>, needle: PyObjectRef, vm: &VirtualMachine) -> PyResult {
let new_args = subs_parameters(
|vm| self.repr(vm),
self.args.clone(),
self.parameters.clone(),
zelf.to_owned().into(),
zelf.args.clone(),
zelf.parameters.clone(),
needle,
vm,
)?;

Ok(
PyGenericAlias::new(self.origin.clone(), new_args.to_pyobject(vm), vm)
PyGenericAlias::new(zelf.origin.clone(), new_args.to_pyobject(vm), vm)
.into_pyobject(vm),
)
}
Expand Down Expand Up @@ -277,6 +278,18 @@ fn tuple_index(vec: &[PyObjectRef], item: &PyObjectRef) -> Option<usize> {
vec.iter().position(|element| element.is(item))
}

fn is_unpacked_typevartuple(arg: &PyObjectRef, vm: &VirtualMachine) -> PyResult<bool> {
if arg.class().is(vm.ctx.types.type_type) {
return Ok(false);
}

if let Ok(attr) = arg.get_attr(identifier!(vm, __typing_is_unpacked_typevartuple__), vm) {
attr.try_to_bool(vm)
} else {
Ok(false)
}
}

fn subs_tvars(
obj: PyObjectRef,
params: &PyTupleRef,
Expand Down Expand Up @@ -324,22 +337,40 @@ fn subs_tvars(
}

// _Py_subs_parameters
pub fn subs_parameters<F: Fn(&VirtualMachine) -> PyResult<String>>(
repr: F,
pub fn subs_parameters(
alias: PyObjectRef, // The GenericAlias object itself
args: PyTupleRef,
parameters: PyTupleRef,
needle: PyObjectRef,
vm: &VirtualMachine,
) -> PyResult<PyTupleRef> {
let num_params = parameters.len();
if num_params == 0 {
return Err(vm.new_type_error(format!("There are no type variables left in {}", repr(vm)?)));
return Err(vm.new_type_error(format!("{} is not a generic class", alias.repr(vm)?)));
}

let items = needle.try_to_ref::<PyTuple>(vm);
// Handle __typing_prepare_subst__ for each parameter
// Following CPython: each prepare function transforms the args
let mut prepared_args = needle.clone();

// Ensure args is a tuple
if prepared_args.try_to_ref::<PyTuple>(vm).is_err() {
prepared_args = PyTuple::new_ref(vec![prepared_args], &vm.ctx).into();
}

for param in parameters.iter() {
if let Ok(prepare) = param.get_attr(identifier!(vm, __typing_prepare_subst__), vm) {
if !prepare.is(&vm.ctx.none) {
// Call prepare(cls, args) where cls is the GenericAlias
prepared_args = prepare.call((alias.clone(), prepared_args), vm)?;
}
}
}

let items = prepared_args.try_to_ref::<PyTuple>(vm);
let arg_items = match items {
Ok(tuple) => tuple.as_slice(),
Err(_) => std::slice::from_ref(&needle),
Err(_) => std::slice::from_ref(&prepared_args),
};

let num_items = arg_items.len();
Expand All @@ -362,40 +393,82 @@ pub fn subs_parameters<F: Fn(&VirtualMachine) -> PyResult<String>>(

let min_required = num_params - params_with_defaults;
if num_items < min_required {
let repr_str = alias.repr(vm)?;
return Err(vm.new_type_error(format!(
"Too few arguments for {}; actual {}, expected at least {}",
repr(vm)?,
num_items,
min_required
"Too few arguments for {repr_str}; actual {num_items}, expected at least {min_required}"
)));
}
} else if num_items > num_params {
let repr_str = alias.repr(vm)?;
return Err(vm.new_type_error(format!(
"Too many arguments for {}; actual {}, expected {}",
repr(vm)?,
num_items,
num_params
"Too many arguments for {repr_str}; actual {num_items}, expected {num_params}"
)));
}

let mut new_args = Vec::new();
let mut new_args = Vec::with_capacity(args.len());

for arg in args.iter() {
// Skip bare Python classes
if arg.class().is(vm.ctx.types.type_type) {
new_args.push(arg.clone());
continue;
}

// Check if this is an unpacked TypeVarTuple
let unpack = is_unpacked_typevartuple(arg, vm)?;

// Check for __typing_subst__ attribute directly (like CPython)
if let Ok(subst) = arg.get_attr(identifier!(vm, __typing_subst__), vm) {
let idx = tuple_index(parameters.as_slice(), arg).unwrap();
if idx < num_items {
// Call __typing_subst__ with the argument
let substituted = subst.call((arg_items[idx].clone(),), vm)?;
new_args.push(substituted);
if let Some(idx) = tuple_index(parameters.as_slice(), arg) {
if idx < num_items {
// Call __typing_subst__ with the argument
let substituted = subst.call((arg_items[idx].clone(),), vm)?;

if unpack {
// Unpack the tuple if it's a TypeVarTuple
if let Ok(tuple) = substituted.try_to_ref::<PyTuple>(vm) {
for elem in tuple.iter() {
new_args.push(elem.clone());
}
} else {
new_args.push(substituted);
}
} else {
new_args.push(substituted);
}
} else {
// Use default value if available
if let Ok(default_val) = vm.call_method(arg, "__default__", ()) {
if !default_val.is(&vm.ctx.typing_no_default) {
new_args.push(default_val);
} else {
return Err(vm.new_type_error(format!(
"No argument provided for parameter at index {idx}"
)));
}
} else {
return Err(vm.new_type_error(format!(
"No argument provided for parameter at index {idx}"
)));
}
}
} else {
// CPython doesn't support default values in this context
return Err(
vm.new_type_error(format!("No argument provided for parameter at index {idx}"))
);
new_args.push(arg.clone());
}
} else {
new_args.push(subs_tvars(arg.clone(), &parameters, arg_items, vm)?);
let subst_arg = subs_tvars(arg.clone(), &parameters, arg_items, vm)?;
if unpack {
// Unpack the tuple if it's a TypeVarTuple
if let Ok(tuple) = subst_arg.try_to_ref::<PyTuple>(vm) {
for elem in tuple.iter() {
new_args.push(elem.clone());
}
} else {
new_args.push(subst_arg);
}
} else {
new_args.push(subst_arg);
}
}
}

Expand All @@ -406,7 +479,8 @@ impl AsMapping for PyGenericAlias {
fn as_mapping() -> &'static PyMappingMethods {
static AS_MAPPING: LazyLock<PyMappingMethods> = LazyLock::new(|| PyMappingMethods {
subscript: atomic_func!(|mapping, needle, vm| {
PyGenericAlias::mapping_downcast(mapping).__getitem__(needle.to_owned(), vm)
let zelf = PyGenericAlias::mapping_downcast(mapping);
PyGenericAlias::__getitem__(zelf.to_owned(), needle.to_owned(), vm)
}),
..PyMappingMethods::NOT_IMPLEMENTED
});
Expand Down Expand Up @@ -490,6 +564,13 @@ impl Representable for PyGenericAlias {
}
}

impl Iterable for PyGenericAlias {
fn iter(zelf: PyRef<Self>, vm: &VirtualMachine) -> PyResult {
// Return an iterator over the args tuple
Ok(zelf.args.clone().to_pyobject(vm).get_iter(vm)?.into())
}
}

pub fn init(context: &Context) {
let generic_alias_type = &context.types.generic_alias_type;
PyGenericAlias::extend_class(context, generic_alias_type);
Expand Down
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