avm2: Correctly set XML attribute with namespace

core/src/avm2/e4x.rs

@@ -212,6 +212,7 @@ impl<'gc> E4XNode<'gc> {
 
     pub fn attribute(
         mc: &Mutation<'gc>,
+        namespace: Option<E4XNamespace<'gc>>,
         name: AvmString<'gc>,
         value: AvmString<'gc>,
         parent: Option<E4XNode<'gc>>,
@@ -220,7 +221,7 @@ impl<'gc> E4XNode<'gc> {
             mc,
             E4XNodeData {
                 parent,
-                namespace: None,
+                namespace: namespace.map(Box::new),
                 local_name: Some(name),
                 kind: E4XNodeKind::Attribute(value),
                 notification: None,

core/src/avm2/object/xml_list_object.rs

@@ -722,6 +722,7 @@ impl<'gc> TObject<'gc> for XmlListObject<'gc> {
                                 // 2.c.iv.3. Let y.[[Class]] = "attribute"
                                 E4XNode::attribute(
                                     activation.gc(),
+                                    x.explicit_namespace().map(E4XNamespace::new_uri),
                                     x.local_name().unwrap(),
                                     "".into(),
                                     r,

core/src/avm2/object/xml_object.rs

@@ -511,7 +511,8 @@ impl<'gc> TObject<'gc> for XmlObject<'gc> {
             let Some(local_name) = name.local_name() else {
                 return Err(format!("Cannot set attribute {:?} without a local name", name).into());
             };
-            let new_attr = E4XNode::attribute(mc, local_name, value, Some(self.node()));
+            let ns = name.explicit_namespace().map(E4XNamespace::new_uri);
+            let new_attr = E4XNode::attribute(mc, ns, local_name, value, Some(self.node()));
 
             let node = self.0.node.get();
             let mut kind = node.kind_mut(mc);

tests/tests/swfs/from_avmplus/e4x/Expressions/e11_1_2/test.toml

@@ -1,2 +1 @@
 num_ticks = 1
-known_failure = true # https://github.com/ruffle-rs/ruffle/issues/12351