Fix set in-place operators with self argument

HueCodes · HueCodes · commit 7a72db2a4148 · 2026-01-05T18:11:43.000-08:00
diff --git a/crates/vm/src/builtins/set.rs b/crates/vm/src/builtins/set.rs
@@ -730,8 +730,10 @@ impl PySet {
 
     #[pymethod]
     fn __iand__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {
-        zelf.inner
-            .intersection_update(std::iter::once(set.into_iterable(vm)?), vm)?;
+        if !set.is_same_object(zelf.as_object()) {
+            zelf.inner
+                .intersection_update(std::iter::once(set.into_iterable(vm)?), vm)?;
+        }
         Ok(zelf)
     }
 
@@ -743,8 +745,12 @@ impl PySet {
 
     #[pymethod]
     fn __isub__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {
-        zelf.inner
-            .difference_update(set.into_iterable_iter(vm)?, vm)?;
+        if set.is_same_object(zelf.as_object()) {
+            zelf.inner.clear();
+        } else {
+            zelf.inner
+                .difference_update(set.into_iterable_iter(vm)?, vm)?;
+        }
         Ok(zelf)
     }
 
@@ -761,8 +767,12 @@ impl PySet {
 
     #[pymethod]
     fn __ixor__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {
-        zelf.inner
-            .symmetric_difference_update(set.into_iterable_iter(vm)?, vm)?;
+        if set.is_same_object(zelf.as_object()) {
+            zelf.inner.clear();
+        } else {
+            zelf.inner
+                .symmetric_difference_update(set.into_iterable_iter(vm)?, vm)?;
+        }
         Ok(zelf)
     }
 
@@ -1251,6 +1261,10 @@ struct AnySet {
 }
 
 impl AnySet {
+    fn is_same_object(&self, other: &PyObject) -> bool {
+        self.object.is(other)
+    }
+
     fn into_iterable(self, vm: &VirtualMachine) -> PyResult<ArgIterable> {
         self.object.try_into_value(vm)
     }
diff --git a/extra_tests/snippets/builtin_set.py b/extra_tests/snippets/builtin_set.py
@@ -200,6 +200,18 @@ class S(set):
 with assert_raises(TypeError):
     a &= [1, 2, 3]
 
+a = set([1, 2, 3])
+a &= a
+assert a == set([1, 2, 3])
+
+a = set([1, 2, 3])
+a -= a
+assert a == set()
+
+a = set([1, 2, 3])
+a ^= a
+assert a == set()
+
 a = set([1, 2, 3])
 a.difference_update([3, 4, 5])
 assert a == set([1, 2])
