xml: Silently fail in `insert_child`

Instead of returning a `Result` which is anyway always handled with
a `log::warn!()`, simply `log::warn!()` in place of errors. This
removes the last 3 remaining `Error` enum members besides `InvalidXml`.

core/src/avm1/globals/xml_node.rs

@@ -5,7 +5,6 @@ use crate::avm1::error::Error;
 use crate::avm1::object::xml_node_object::XmlNodeObject;
 use crate::avm1::property_decl::{define_properties_on, Declaration};
 use crate::avm1::{ArrayObject, Object, TObject, Value};
-use crate::avm_warn;
 use crate::string::AvmString;
 use crate::xml;
 use crate::xml::XmlNode;
@@ -76,15 +75,7 @@ fn append_child<'gc>(
     ) {
         if !xmlnode.has_child(child_xmlnode) {
             let position = xmlnode.children_len();
-            if let Err(e) =
-                xmlnode.insert_child(activation.context.gc_context, position, child_xmlnode)
-            {
-                avm_warn!(
-                    activation,
-                    "Couldn't insert_child inside of XMLNode.appendChild: {}",
-                    e
-                );
-            }
+            xmlnode.insert_child(activation.context.gc_context, position, child_xmlnode);
         }
     }
 
@@ -105,15 +96,7 @@ fn insert_before<'gc>(
     ) {
         if !xmlnode.has_child(child_xmlnode) {
             if let Some(position) = xmlnode.child_position(insertpoint_xmlnode) {
-                if let Err(e) =
-                    xmlnode.insert_child(activation.context.gc_context, position, child_xmlnode)
-                {
-                    avm_warn!(
-                        activation,
-                        "Couldn't insert_child inside of XMLNode.insertBefore: {}",
-                        e
-                    );
-                }
+                xmlnode.insert_child(activation.context.gc_context, position, child_xmlnode);
             }
         }
     }

core/src/avm1/object/xml_object.rs

@@ -174,7 +174,7 @@ impl<'gc> XmlObject<'gc> {
                     open_tags
                         .last_mut()
                         .unwrap()
-                        .append_child(activation.context.gc_context, child)?;
+                        .append_child(activation.context.gc_context, child);
                     open_tags.push(child);
                 }
                 Event::Empty(bs) => {
@@ -187,7 +187,7 @@ impl<'gc> XmlObject<'gc> {
                     open_tags
                         .last_mut()
                         .unwrap()
-                        .append_child(activation.context.gc_context, child)?;
+                        .append_child(activation.context.gc_context, child);
                 }
                 Event::End(_) => {
                     open_tags.pop();
@@ -204,7 +204,7 @@ impl<'gc> XmlObject<'gc> {
                         open_tags
                             .last_mut()
                             .unwrap()
-                            .append_child(activation.context.gc_context, child)?;
+                            .append_child(activation.context.gc_context, child);
                     }
                 }
                 Event::DocType(bt) => {

core/src/xml/error.rs

@@ -14,15 +14,6 @@ use thiserror::Error;
 pub enum Error {
     #[error("Invalid XML")]
     InvalidXml(#[from] ParseError),
-
-    #[error("Cannot adopt other document roots")]
-    CannotAdoptRoot,
-
-    #[error("Cannot adopt children into non-child-bearing node")]
-    CannotAdoptHere,
-
-    #[error("Cannot insert child into itself")]
-    CannotInsertIntoSelf,
 }
 
 impl From<FromUtf8Error> for Error {

core/src/xml/tree.rs

@@ -336,9 +336,6 @@ impl<'gc> XmlNode<'gc> {
     /// position in the tree. This may remove it from any existing trees or
     /// documents.
     ///
-    /// This function yields an error if appending to a Node that cannot accept
-    /// children. In that case, no modification will be made to the node.
-    ///
     /// The `position` parameter is the position of the new child in
     /// this node's children list. This is used to find and link the child's
     /// siblings to each other.
@@ -347,18 +344,21 @@ impl<'gc> XmlNode<'gc> {
         mc: MutationContext<'gc, '_>,
         position: usize,
         mut child: XmlNode<'gc>,
-    ) -> Result<(), Error> {
+    ) {
         let is_cyclic = self
             .ancestors()
             .any(|ancestor| GcCell::ptr_eq(ancestor.0, child.0));
         if is_cyclic {
-            return Err(Error::CannotInsertIntoSelf);
+            return;
         }
 
         match &mut *self.0.write(mc) {
             XmlNodeData::DocumentRoot { children, .. } | XmlNodeData::Element { children, .. } => {
                 let old_parent = match *child.0.read() {
-                    XmlNodeData::DocumentRoot { .. } => return Err(Error::CannotAdoptRoot),
+                    XmlNodeData::DocumentRoot { .. } => {
+                        log::warn!("Cannot adopt other document roots");
+                        return;
+                    }
                     XmlNodeData::Element { parent, .. } | XmlNodeData::Text { parent, .. } => {
                         parent
                     }
@@ -390,20 +390,16 @@ impl<'gc> XmlNode<'gc> {
                     .and_then(|p| children.get(p).cloned());
                 child.adopt_siblings(mc, new_prev, new_next);
             }
-            _ => return Err(Error::CannotAdoptHere),
+            XmlNodeData::Text { .. } => {
+                log::warn!("Text nodes cannot have children");
+            }
         }
-
-        Ok(())
     }
 
     /// Append a child element into the end of the child list of an Element
     /// node.
-    pub fn append_child(
-        &mut self,
-        mc: MutationContext<'gc, '_>,
-        child: XmlNode<'gc>,
-    ) -> Result<(), Error> {
-        self.insert_child(mc, self.children_len(), child)
+    pub fn append_child(&mut self, mc: MutationContext<'gc, '_>, child: XmlNode<'gc>) {
+        self.insert_child(mc, self.children_len(), child);
     }
 
     /// Remove this node from its parent.
@@ -661,9 +657,7 @@ impl<'gc> XmlNode<'gc> {
 
         if deep {
             for (position, child) in self.children().enumerate() {
-                clone
-                    .insert_child(gc_context, position, child.duplicate(gc_context, deep))
-                    .expect("If I can see my children then my clone should accept children");
+                clone.insert_child(gc_context, position, child.duplicate(gc_context, deep));
             }
         }