From c9987f9488fde97c5f919cd1d1d9453793411e23 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Sat, 15 May 2021 11:32:34 +0200
Subject: [PATCH] Optimize `Rope::append` by merging chunks only when they're
 underflowing

---
 zed/src/editor/buffer/rope.rs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/zed/src/editor/buffer/rope.rs b/zed/src/editor/buffer/rope.rs
index 994022deee..78ed156308 100644
--- a/zed/src/editor/buffer/rope.rs
+++ b/zed/src/editor/buffer/rope.rs
@@ -26,8 +26,12 @@ impl Rope {
         let mut chunks = rope.chunks.cursor::<(), ()>();
         chunks.next();
         if let Some(chunk) = chunks.item() {
-            self.push(&chunk.0);
-            chunks.next();
+            if self.chunks.last().map_or(false, |c| c.0.len() < CHUNK_BASE)
+                || chunk.0.len() < CHUNK_BASE
+            {
+                self.push(&chunk.0);
+                chunks.next();
+            }
         }
 
         self.chunks.push_tree(chunks.suffix(&()), &());