From 9b86032dc111118e217f080843fde87f87fd8421 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?JB=20Onofr=C3=A9?= <jb@nanthrax.net>
Date: Sun, 1 Nov 2026 06:43:49 +0100
Subject: [PATCH] GH-238: Stop TestNettyAllocator wrapping Netty's empty buffer
 in a 1024-byte ArrowBuf

TestNettyAllocator.testMemoryUsage wrapped a 1024-byte NO_OP ArrowBuf around
the memory address of PooledByteBufAllocatorL's empty buffer, whose native
allocation is only a few bytes. The test only reads the address today, but
any read or write through that buffer would run past the end of the native
allocation, as in TestEmptyArrowBuf (#1426).

The buffer isn't needed: the memory usage log the test waits for comes from
the status thread that the PooledByteBufAllocatorL constructor starts when
TRACE logging is enabled. Construct the allocator directly instead.

Closes #238.
---
 .../arrow/memory/netty/TestNettyAllocator.java       | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/memory/memory-netty/src/test/java/org/apache/arrow/memory/netty/TestNettyAllocator.java b/memory/memory-netty/src/test/java/org/apache/arrow/memory/netty/TestNettyAllocator.java
index 5be42ecb08..ffbec4127f 100644
--- a/memory/memory-netty/src/test/java/org/apache/arrow/memory/netty/TestNettyAllocator.java
+++ b/memory/memory-netty/src/test/java/org/apache/arrow/memory/netty/TestNettyAllocator.java
@@ -25,8 +25,6 @@
 import io.netty.buffer.PooledByteBufAllocatorL;
 import java.util.Collections;
 import java.util.stream.Collectors;
-import org.apache.arrow.memory.ArrowBuf;
-import org.apache.arrow.memory.ReferenceManager;
 import org.junit.jupiter.api.Test;
 import org.slf4j.LoggerFactory;
 
@@ -43,14 +41,8 @@ public void testMemoryUsage() {
       logger.setLevel(Level.TRACE);
       logger.addAppender(memoryLogsAppender);
       memoryLogsAppender.start();
-      try (ArrowBuf buf =
-          new ArrowBuf(
-              ReferenceManager.NO_OP,
-              null,
-              1024,
-              new PooledByteBufAllocatorL().empty.memoryAddress())) {
-        buf.memoryAddress();
-      }
+      // Creating the allocator with TRACE logging enabled starts the thread that logs memory usage.
+      new PooledByteBufAllocatorL();
       boolean result = false;
       long startTime = System.currentTimeMillis();
       while ((System.currentTimeMillis() - startTime)