From abd883a7ab4c896b02712936a981f7c50eb979d1 Mon Sep 17 00:00:00 2001
From: Nhat Nguyen <nhat.nguyen@elastic.co>
Date: Fri, 10 Oct 2025 22:46:36 -0700
Subject: [PATCH] Fix getBytesRef in ConstantBytesRefVector

---
 .../compute/data/ConstantBytesRefVector.java              | 7 +++++--
 .../elasticsearch/compute/data/X-ConstantVector.java.st   | 8 ++++++--
 .../org/elasticsearch/compute/data/BasicBlockTests.java   | 6 ++++++
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/x-pack/plugin/esql/compute/src/main/generated-src/org/elasticsearch/compute/data/ConstantBytesRefVector.java b/x-pack/plugin/esql/compute/src/main/generated-src/org/elasticsearch/compute/data/ConstantBytesRefVector.java
index 4cd838d921c34..545a7ad0f9684 100644
--- a/x-pack/plugin/esql/compute/src/main/generated-src/org/elasticsearch/compute/data/ConstantBytesRefVector.java
+++ b/x-pack/plugin/esql/compute/src/main/generated-src/org/elasticsearch/compute/data/ConstantBytesRefVector.java
@@ -32,8 +32,11 @@ final class ConstantBytesRefVector extends AbstractVector implements BytesRefVec
     }
 
     @Override
-    public BytesRef getBytesRef(int position, BytesRef ignore) {
-        return value;
+    public BytesRef getBytesRef(int position, BytesRef scratch) {
+        scratch.bytes = value.bytes;
+        scratch.offset = value.offset;
+        scratch.length = value.length;
+        return scratch;
     }
 
     @Override
diff --git a/x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/data/X-ConstantVector.java.st b/x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/data/X-ConstantVector.java.st
index bac513d0b3b4d..fa714560f1617 100644
--- a/x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/data/X-ConstantVector.java.st
+++ b/x-pack/plugin/esql/compute/src/main/java/org/elasticsearch/compute/data/X-ConstantVector.java.st
@@ -40,11 +40,15 @@ $endif$
 
     @Override
 $if(BytesRef)$
-    public BytesRef getBytesRef(int position, BytesRef ignore) {
+    public BytesRef getBytesRef(int position, BytesRef scratch) {
+        scratch.bytes = value.bytes;
+        scratch.offset = value.offset;
+        scratch.length = value.length;
+        return scratch;
 $else$
     public $type$ get$Type$(int position) {
-$endif$
         return value;
+$endif$
     }
 
     @Override
diff --git a/x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/data/BasicBlockTests.java b/x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/data/BasicBlockTests.java
index e0a18c79307c5..27759402efd9d 100644
--- a/x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/data/BasicBlockTests.java
+++ b/x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/data/BasicBlockTests.java
@@ -818,6 +818,12 @@ public void testConstantBytesRefBlock() {
             assertInsertNulls(block);
             assertDeepCopy(block);
             releaseAndAssertBreaker(block);
+            // modify the offset
+            var v0 = block.getBytesRef(randomInt(positionCount), new BytesRef());
+            var v1 = block.getBytesRef(randomInt(positionCount), new BytesRef());
+            v1.length = 0;
+            var v2 = block.getBytesRef(randomInt(positionCount), new BytesRef());
+            assertThat(v2, equalTo(v0));
         }
     }