avm2+tests: Allow concating XMLLists; add test

core/src/avm2/activation.rs

@@ -11,6 +11,7 @@ use crate::avm2::error::{
 use crate::avm2::method::{BytecodeMethod, Method, ParamConfig};
 use crate::avm2::object::{
     ArrayObject, ByteArrayObject, ClassObject, FunctionObject, NamespaceObject, ScriptObject,
+    XmlListObject,
 };
 use crate::avm2::object::{Object, TObject};
 use crate::avm2::scope::{search_scope_stack, Scope, ScopeChain};
@@ -2114,6 +2115,10 @@ impl<'a, 'gc> Activation<'a, 'gc> {
                 value1.coerce_to_string(self)?,
                 s,
             )),
+            (
+                Value::Object(Object::XmlListObject(value1)),
+                Value::Object(Object::XmlListObject(value2)),
+            ) => Value::Object(XmlListObject::concat(self, value1, value2).into()),
             (value1, value2) => {
                 let prim_value1 = value1.coerce_to_primitive(None, self)?;
                 let prim_value2 = value2.coerce_to_primitive(None, self)?;

core/src/avm2/object/xml_list_object.rs

@@ -136,6 +136,23 @@ impl<'gc> XmlListObject<'gc> {
 
         Ok(false)
     }
+
+    pub fn concat(
+        activation: &mut Activation<'_, 'gc>,
+        left: XmlListObject<'gc>,
+        right: XmlListObject<'gc>,
+    ) -> XmlListObject<'gc> {
+        if left.length() == 0 {
+            right
+        } else if right.length() == 0 {
+            left
+        } else {
+            let mut out = vec![];
+            out.extend(left.children().clone());
+            out.extend(right.children().clone());
+            Self::new(activation, out, None)
+        }
+    }
 }
 
 #[derive(Clone, Collect)]

tests/tests/swfs/avm2/xml_list_concat/Test.as

@@ -0,0 +1,36 @@
+package
+{
+    import flash.display.Sprite;
+
+    public class Test extends Sprite
+    {
+    }
+}
+
+var test:XML = <root>
+                <list1>
+                    <item>
+                        <text>Hello</text>
+                    </item>
+                    <item>
+                        <text>World</text>
+                    </item>
+                </list1>
+                <list2>
+                    <item>
+                        <text>from</text>
+                    </item>
+                    <item>
+                        <text>Ruffle!</text>
+                    </item>
+                </list2>
+               </root>;
+
+var list:XMLList = test.list1.item + test.list2.item;
+
+for (var i:int = 0; i < list.length(); i++)
+{
+    var val:XML = list[i];
+
+    trace(val.text[0].toString());
+}

tests/tests/swfs/avm2/xml_list_concat/output.txt

@@ -0,0 +1,4 @@
+Hello
+World
+from
+Ruffle!

tests/tests/swfs/avm2/xml_list_concat/test.toml

@@ -0,0 +1 @@
+num_ticks = 1