(kafka) branch 3.9 updated: KAFKA-20361 Fix LazyDownConversionRecordsTest in using zlib-ng (#21881)

[chia7712]

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chia7712 pushed a commit to branch 3.9
in repository https://gitbox.apache.org/repos/asf/kafka.git


The following commit(s) were added to refs/heads/3.9 by this push:
     new 96e06ebe888 KAFKA-20361 Fix LazyDownConversionRecordsTest in using 
zlib-ng (#21881)
96e06ebe888 is described below

commit 96e06ebe888059eb3178dada8aaac1cd85999d7a
Author: Murali Basani <muralidhar.bas...@aiven.io>
AuthorDate: Tue Mar 31 16:55:53 2026 +0200

    KAFKA-20361 Fix LazyDownConversionRecordsTest in using zlib-ng (#21881)
    
    The test's write loop passed bytesToConvert - written as the remaining
    parameter to LazyDownConversionRecordsSend.writeTo(). This shrinks with
    each batch written, and the last batch gets truncated via
    Math.min(batchSize, remaining) when total V1 size exceeds V2 size —
    which happens with zlib-ng due to its longer match sizes compressing V1
    format less efficiently.
    
    Fix: pass bytesToConvert (constant) as remaining so no individual batch
    is ever truncated, regardless of the compression library used.
    
    Reviewers: Chia-Ping Tsai <chia7...@gmail.com>
---
 .../org/apache/kafka/common/record/LazyDownConversionRecordsTest.java  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git 
a/clients/src/test/java/org/apache/kafka/common/record/LazyDownConversionRecordsTest.java
 
b/clients/src/test/java/org/apache/kafka/common/record/LazyDownConversionRecordsTest.java
index 59ac60e3a80..33ed91f26ff 100644
--- 
a/clients/src/test/java/org/apache/kafka/common/record/LazyDownConversionRecordsTest.java
+++ 
b/clients/src/test/java/org/apache/kafka/common/record/LazyDownConversionRecordsTest.java
@@ -154,7 +154,8 @@ public class LazyDownConversionRecordsTest {
             ByteBuffer convertedRecordsBuffer;
             try (TransferableChannel channel = 
toTransferableChannel(FileChannel.open(outputFile.toPath(), 
StandardOpenOption.READ, StandardOpenOption.WRITE))) {
                 int written = 0;
-                while (written < bytesToConvert) written += 
lazySend.writeTo(channel, written, bytesToConvert - written);
+                // Use bytesToConvert as remaining to avoid truncating batches 
when V1 is larger than V2 (e.g. zlib-ng)
+                while (written < bytesToConvert) written += 
lazySend.writeTo(channel, written, bytesToConvert);
                 try (FileRecords convertedRecords = 
FileRecords.open(outputFile, true, written, false)) {
                     convertedRecordsBuffer = 
ByteBuffer.allocate(convertedRecords.sizeInBytes());
                     convertedRecords.readInto(convertedRecordsBuffer, 0);