From 05e06e51ec3429d45d75c4c7d61e55c6c6dee2f2 Mon Sep 17 00:00:00 2001
From: Ignacio Vera <ivera@apache.org>
Date: Mon, 21 Oct 2024 07:36:46 +0200
Subject: [PATCH] Use growNoCopy when copying bytes in BytesRefBuilder (#13930)

---
 lucene/CHANGES.txt                               |  2 ++
 .../org/apache/lucene/util/BytesRefBuilder.java  | 16 ++++++++--------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 5d9343bca2a..15a72c66a63 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -53,6 +53,8 @@ Optimizations
 * GITHUB#13800: MaxScoreBulkScorer now recomputes scorer partitions when the
   minimum competitive allows for a more favorable partitioning. (Adrien Grand)
 
+* GITHUB#13930: Use growNoCopy when copying bytes in BytesRefBuilder. (Ignacio Vera)
+
 Bug Fixes
 ---------------------
 * GITHUB#13832: Fixed an issue where the DefaultPassageFormatter.format method did not format passages as intended
diff --git a/lucene/core/src/java/org/apache/lucene/util/BytesRefBuilder.java b/lucene/core/src/java/org/apache/lucene/util/BytesRefBuilder.java
index 21adf0c60da..27fc4337d25 100644
--- a/lucene/core/src/java/org/apache/lucene/util/BytesRefBuilder.java
+++ b/lucene/core/src/java/org/apache/lucene/util/BytesRefBuilder.java
@@ -100,8 +100,10 @@ public class BytesRefBuilder {
    * #clear()} and then {@link #append(byte[], int, int)}.
    */
   public void copyBytes(byte[] b, int off, int len) {
-    clear();
-    append(b, off, len);
+    assert ref.offset == 0;
+    ref.length = len;
+    growNoCopy(len);
+    System.arraycopy(b, off, ref.bytes, 0, len);
   }
 
   /**
@@ -109,8 +111,7 @@ public class BytesRefBuilder {
    * #clear()} and then {@link #append(BytesRef)}.
    */
   public void copyBytes(BytesRef ref) {
-    clear();
-    append(ref);
+    copyBytes(ref.bytes, ref.offset, ref.length);
   }
 
   /**
@@ -118,8 +119,7 @@ public class BytesRefBuilder {
    * #clear()} and then {@link #append(BytesRefBuilder)}.
    */
   public void copyBytes(BytesRefBuilder builder) {
-    clear();
-    append(builder);
+    copyBytes(builder.get());
   }
 
   /**
@@ -135,7 +135,7 @@ public class BytesRefBuilder {
    * text.
    */
   public void copyChars(CharSequence text, int off, int len) {
-    grow(UnicodeUtil.maxUTF8Length(len));
+    growNoCopy(UnicodeUtil.maxUTF8Length(len));
     ref.length = UnicodeUtil.UTF16toUTF8(text, off, len, ref.bytes);
   }
 
@@ -144,7 +144,7 @@ public class BytesRefBuilder {
    * text.
    */
   public void copyChars(char[] text, int off, int len) {
-    grow(UnicodeUtil.maxUTF8Length(len));
+    growNoCopy(UnicodeUtil.maxUTF8Length(len));
     ref.length = UnicodeUtil.UTF16toUTF8(text, off, len, ref.bytes);
   }