From 59b804335a0d1969ffaaba0259873444dee3fea4 Mon Sep 17 00:00:00 2001
From: kennethloeffler <kenloef@gmail.com>
Date: Tue, 29 Oct 2024 19:39:49 +0000
Subject: [PATCH 1/2] Don't create queue in WeakDom::insert for instances with
 no children

---
 rbx_dom_weak/src/dom.rs | 44 +++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/rbx_dom_weak/src/dom.rs b/rbx_dom_weak/src/dom.rs
index 0d5ae8c22..c57f8ee27 100644
--- a/rbx_dom_weak/src/dom.rs
+++ b/rbx_dom_weak/src/dom.rs
@@ -109,16 +109,13 @@ impl WeakDom {
     /// ## Panics
     /// Panics if `parent_ref` is some and does not refer to an instance in the DOM.
     pub fn insert(&mut self, parent_ref: Ref, root_builder: InstanceBuilder) -> Ref {
-        let root_referent = root_builder.referent;
-
-        // Rather than performing this movement recursively, we instead use a
-        // queue that we load the children of each `InstanceBuilder` into.
-        // Then we can just iter through that.
-        let mut queue = VecDeque::with_capacity(1);
-        queue.push_back((parent_ref, root_builder));
-
-        while let Some((parent, builder)) = queue.pop_front() {
-            self.inner_insert(
+        fn insert(
+            dom: &mut WeakDom,
+            builder: InstanceBuilder,
+            parent: Ref,
+            queue: Option<&mut VecDeque<(Ref, InstanceBuilder)>>,
+        ) {
+            dom.inner_insert(
                 builder.referent,
                 Instance {
                     referent: builder.referent,
@@ -131,15 +128,36 @@ impl WeakDom {
             );
 
             if parent.is_some() {
-                self.instances
+                dom.instances
                     .get_mut(&parent)
                     .unwrap_or_else(|| panic!("cannot insert into parent that does not exist"))
                     .children
                     .push(builder.referent);
             }
 
-            for child in builder.children {
-                queue.push_back((builder.referent, child));
+            if let Some(queue) = queue {
+                for child in builder.children {
+                    queue.push_back((builder.referent, child));
+                }
+            }
+        }
+
+        let root_referent = root_builder.referent;
+
+        // Fast path: if the builder does not have any children, then we don't have to
+        // construct a queue to keep track of descendants for insertion, avoiding a heap
+        // allocation.
+        if root_builder.children.len() == 0 {
+            insert(self, root_builder, parent_ref, None);
+        } else {
+            // Rather than performing this movement recursively, we instead use a
+            // queue that we load the children of each `InstanceBuilder` into.
+            // Then we can just iter through that.
+            let mut queue = VecDeque::with_capacity(1);
+            queue.push_back((parent_ref, root_builder));
+
+            while let Some((parent, builder)) = queue.pop_front() {
+                insert(self, builder, parent, Some(&mut queue));
             }
         }
 

From 5a46fb7c37c1e3b61c26c26ccbd818ba148394d3 Mon Sep 17 00:00:00 2001
From: kennethloeffler <kenloef@gmail.com>
Date: Tue, 29 Oct 2024 19:55:38 +0000
Subject: [PATCH 2/2] Nice

---
 rbx_dom_weak/src/dom.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rbx_dom_weak/src/dom.rs b/rbx_dom_weak/src/dom.rs
index c57f8ee27..3b43ea3f0 100644
--- a/rbx_dom_weak/src/dom.rs
+++ b/rbx_dom_weak/src/dom.rs
@@ -147,7 +147,7 @@ impl WeakDom {
         // Fast path: if the builder does not have any children, then we don't have to
         // construct a queue to keep track of descendants for insertion, avoiding a heap
         // allocation.
-        if root_builder.children.len() == 0 {
+        if root_builder.children.is_empty() {
             insert(self, root_builder, parent_ref, None);
         } else {
             // Rather than performing this movement recursively, we instead use a