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Short-circuit identity in rich_compare_bool for Eq/Ne (PyObject_RichCompareBool parity) #7734

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Merged
youknowone merged 2 commits into from
Apr 29, 2026
Merged

Short-circuit identity in rich_compare_bool for Eq/Ne (PyObject_RichCompareBool parity) #7734

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fe4c8b3
Short-circuit identity in rich_compare_bool for Eq/Ne (PyObject_RichC…
changjoon-park Apr 29, 2026
55c3130
Route proxy comparisons through PyObject_RichCompare
changjoon-park Apr 29, 2026
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1 change: 0 additions & 1 deletion Lib/test/test_dictviews.py
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Original file line number Diff line number Diff line change
Expand Up @@ -292,7 +292,6 @@ def test_copy(self):
self.assertRaises(TypeError, copy.copy, d.values())
self.assertRaises(TypeError, copy.copy, d.items())

@unittest.expectedFailure # TODO: RUSTPYTHON
def test_compare_error(self):
class Exc(Exception):
pass
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11 changes: 7 additions & 4 deletions crates/vm/src/builtins/mappingproxy.rs
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Expand Up @@ -5,7 +5,7 @@ use crate::{
class::PyClassImpl,
common::{hash, lock::LazyLock},
convert::ToPyObject,
function::{ArgMapping, OptionalArg, PyComparisonValue},
function::{ArgMapping, OptionalArg, PyArithmeticValue, PyComparisonValue},
object::{Traverse, TraverseFn},
protocol::{PyMappingMethods, PyNumberMethods, PySequenceMethods},
types::{
Expand Down Expand Up @@ -211,9 +211,12 @@ impl Comparable for PyMappingProxy {
vm: &VirtualMachine,
) -> PyResult<PyComparisonValue> {
let obj = zelf.to_object(vm)?;
Ok(PyComparisonValue::Implemented(
obj.rich_compare_bool(other, op, vm)?,
))
// CPython parity (Objects/descrobject.c::mappingproxy_richcompare):
// delegate to PyObject_RichCompare on the underlying mapping.
let res = obj.rich_compare(other.to_owned(), op, vm)?;
PyArithmeticValue::from_object(vm, res)
.map(|o| o.try_to_bool(vm))
.transpose()
}
}

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11 changes: 7 additions & 4 deletions crates/vm/src/builtins/weakproxy.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ use crate::{
Context, Py, PyObject, PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine, atomic_func,
class::PyClassImpl,
common::hash::PyHash,
function::{OptionalArg, PyComparisonValue, PySetterValue},
function::{OptionalArg, PyArithmeticValue, PyComparisonValue, PySetterValue},
protocol::{PyIter, PyIterReturn, PyMappingMethods, PyNumberMethods, PySequenceMethods},
stdlib::builtins::reversed,
types::{
Expand Down Expand Up @@ -301,9 +301,12 @@ impl Comparable for PyWeakProxy {
vm: &VirtualMachine,
) -> PyResult<PyComparisonValue> {
let obj = zelf.try_upgrade(vm)?;
Ok(PyComparisonValue::Implemented(
obj.rich_compare_bool(other, op, vm)?,
))
// CPython parity (Objects/weakref.c::proxy_richcompare): delegate to
// PyObject_RichCompare on the referent, not the bool variant.
let res = obj.rich_compare(other.to_owned(), op, vm)?;
PyArithmeticValue::from_object(vm, res)
.map(|o| o.try_to_bool(vm))
.transpose()
}
}

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21 changes: 14 additions & 7 deletions crates/vm/src/builtins/weakref.rs
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Expand Up @@ -6,7 +6,7 @@ use crate::common::{
use crate::{
AsObject, Context, Py, PyObject, PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine,
class::PyClassImpl,
function::{FuncArgs, OptionalArg},
function::{FuncArgs, OptionalArg, PyArithmeticValue, PyComparisonValue},
types::{
Callable, Comparable, Constructor, Hashable, Initializer, PyComparisonOp, Representable,
},
Expand Down Expand Up @@ -127,15 +127,22 @@ impl Comparable for PyWeak {
other: &PyObject,
op: PyComparisonOp,
vm: &VirtualMachine,
) -> PyResult<crate::function::PyComparisonValue> {
) -> PyResult<PyComparisonValue> {
op.eq_only(|| {
let other = class_or_notimplemented!(Self, other);
let both = zelf.upgrade().and_then(|s| other.upgrade().map(|o| (s, o)));
let eq = match both {
Some((a, b)) => vm.bool_eq(&a, &b)?,
None => zelf.is(other),
};
Ok(eq.into())
match both {
// CPython parity (Objects/weakref.c::weakref_richcompare): use
// PyObject_RichCompare on the referents, not the bool variant,
// so referent __eq__ runs even when referents share identity.
Some((a, b)) => {
let res = a.rich_compare(b, PyComparisonOp::Eq, vm)?;
PyArithmeticValue::from_object(vm, res)
.map(|obj| obj.try_to_bool(vm))
.transpose()
}
None => Ok(zelf.is(other).into()),
}
})
}
}
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14 changes: 14 additions & 0 deletions crates/vm/src/protocol/object.rs
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Expand Up @@ -348,6 +348,20 @@ impl PyObject {
op_id: PyComparisonOp,
vm: &VirtualMachine,
) -> PyResult<bool> {
// CPython parity: PyObject_RichCompareBool guarantees identity implies
// equality (and inequality is false on identity), short-circuiting
// before dispatch. Collection membership / equality (e.g. `x in [x]`,
// `[nan] == [nan]`) depend on this even when `__eq__` would raise
// or return False. Only Eq/Ne are decidable from identity; ordering
// ops fall through to `_cmp` because Python does not guarantee
// reflexivity for `<`/`<=`/`>`/`>=`.
if self.is(other) {
match op_id {
PyComparisonOp::Eq => return Ok(true),
PyComparisonOp::Ne => return Ok(false),
_ => {}
}
}
match self._cmp(other, op_id, vm)? {
Either::A(obj) => obj.try_to_bool(vm),
Either::B(other) => Ok(other),
Expand Down
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