avm2: Implement XML.prependChild

core/src/avm2/globals/XML.as

@@ -72,6 +72,7 @@ package {
         AS3 native function attribute(name:*):XMLList;
         AS3 native function nodeKind():String;
         AS3 native function appendChild(child:Object):XML;
+        AS3 native function prependChild(child:Object):XML;
         AS3 native function descendants(name:Object = "*"):XMLList;
         AS3 native function text():XMLList;
         AS3 native function toString():String;
@@ -189,6 +190,11 @@ package {
             return self.AS3::appendChild(child);
         };
 
+        prototype.prependChild = function(child:Object):XML {
+            var self:XML = this;
+            return self.AS3::prependChild(child);
+        };
+
         prototype.descendants = function(name:Object):XMLList {
             var self:XML = this;
             return self.AS3::descendants(name);

core/src/avm2/globals/xml.rs

@@ -386,6 +386,21 @@ pub fn append_child<'gc>(
     Ok(this.into())
 }
 
+// ECMA-357 13.4.4.29 XML.prototype.prependChild ( value )
+pub fn prepend_child<'gc>(
+    activation: &mut Activation<'_, 'gc>,
+    this: Object<'gc>,
+    args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    let xml = this.as_xml_object().unwrap();
+    let child = args.get_value(0);
+    // 1. Call the [[Insert]] method of this object with arguments "0" and value
+    xml.node().insert(0, child, activation)?;
+
+    // 2. Return x
+    Ok(xml.into())
+}
+
 pub fn descendants<'gc>(
     activation: &mut Activation<'_, 'gc>,
     this: Object<'gc>,

tests/tests/swfs/from_avmplus/e4x/XML/e13_4_2/test.toml

@@ -1,2 +1 @@
 num_ticks = 1
-known_failure = true

tests/tests/swfs/from_avmplus/e4x/XML/e13_4_4_29/v10/test.toml

@@ -1,2 +1 @@
 num_ticks = 1
-known_failure = true