Fix set in-place operators with self argument

HueCodes · HueCodes · commit 36bace416588 · 2026-01-06T16:02:10.000-08:00
diff --git a/crates/vm/src/builtins/set.rs b/crates/vm/src/builtins/set.rs
@@ -719,8 +719,10 @@ impl PySet {
     }
 
     fn __iand__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {
-        zelf.inner
-            .intersection_update(core::iter::once(set.into_iterable(vm)?), vm)?;
+        if !set.is_same_object(zelf.as_object()) {
+            zelf.inner
+                .intersection_update(core::iter::once(set.into_iterable(vm)?), vm)?;
+        }
         Ok(zelf)
     }
 
@@ -731,8 +733,12 @@ impl PySet {
     }
 
     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)
     }
 
@@ -748,8 +754,12 @@ impl PySet {
     }
 
     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)
     }
 
@@ -1305,6 +1315,10 @@ impl AnySet {
         obj.fast_isinstance(ctx.types.set_type) || obj.fast_isinstance(ctx.types.frozenset_type)
     }
 
+    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])

Original file line number	Diff line number	Diff line change
`@@ -719,8 +719,10 @@ impl PySet {`
`719`	`719`	`}`
`720`	`720`
`721`	`721`	`fn __iand__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {`
`722`		`- zelf.inner`
`723`		`- .intersection_update(core::iter::once(set.into_iterable(vm)?), vm)?;`
	`722`	`+ if !set.is_same_object(zelf.as_object()) {`
	`723`	`+ zelf.inner`
	`724`	`+ .intersection_update(core::iter::once(set.into_iterable(vm)?), vm)?;`
	`725`	`+ }`
`724`	`726`	`Ok(zelf)`
`725`	`727`	`}`
`726`	`728`
`@@ -731,8 +733,12 @@ impl PySet {`
`731`	`733`	`}`
`732`	`734`
`733`	`735`	`fn __isub__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {`
`734`		`- zelf.inner`
`735`		`- .difference_update(set.into_iterable_iter(vm)?, vm)?;`
	`736`	`+ if set.is_same_object(zelf.as_object()) {`
	`737`	`+ zelf.inner.clear();`
	`738`	`+ } else {`
	`739`	`+ zelf.inner`
	`740`	`+ .difference_update(set.into_iterable_iter(vm)?, vm)?;`
	`741`	`+ }`
`736`	`742`	`Ok(zelf)`
`737`	`743`	`}`
`738`	`744`
`@@ -748,8 +754,12 @@ impl PySet {`
`748`	`754`	`}`
`749`	`755`
`750`	`756`	`fn __ixor__(zelf: PyRef<Self>, set: AnySet, vm: &VirtualMachine) -> PyResult<PyRef<Self>> {`
`751`		`- zelf.inner`
`752`		`- .symmetric_difference_update(set.into_iterable_iter(vm)?, vm)?;`
	`757`	`+ if set.is_same_object(zelf.as_object()) {`
	`758`	`+ zelf.inner.clear();`
	`759`	`+ } else {`
	`760`	`+ zelf.inner`
	`761`	`+ .symmetric_difference_update(set.into_iterable_iter(vm)?, vm)?;`
	`762`	`+ }`
`753`	`763`	`Ok(zelf)`
`754`	`764`	`}`
`755`	`765`
`@@ -1305,6 +1315,10 @@ impl AnySet {`
`1305`	`1315`	`obj.fast_isinstance(ctx.types.set_type) \|\| obj.fast_isinstance(ctx.types.frozenset_type)`
`1306`	`1316`	`}`
`1307`	`1317`
	`1318`	`+ fn is_same_object(&self, other: &PyObject) -> bool {`
	`1319`	`+ self.object.is(other)`
	`1320`	`+ }`
	`1321`	`+`
`1308`	`1322`	`fn into_iterable(self, vm: &VirtualMachine) -> PyResult<ArgIterable> {`
`1309`	`1323`	`self.object.try_into_value(vm)`
`1310`	`1324`	`}`