(arrow) branch main updated: GH-38725: [Java] decompression in Lz4CompressionCodec.java does not set writer index (#38840)

[lidavidm]

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lidavidm pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow.git


The following commit(s) were added to refs/heads/main by this push:
     new 596259ee47 GH-38725: [Java] decompression in Lz4CompressionCodec.java 
does not set writer index (#38840)
596259ee47 is described below

commit 596259ee47b5c675b71432743d9bfd196efe08e3
Author: Vibhatha Lakmal Abeykoon <vibha...@users.noreply.github.com>
AuthorDate: Thu Dec 21 19:02:38 2023 +0530

    GH-38725: [Java] decompression in Lz4CompressionCodec.java does not set 
writer index (#38840)
    
    ### Rationale for this change
    
    The `doDecompress` function in `Lz4CompressionCodec` misses writing the 
index when it is compared with the functionality in `ZstdCompressionCodec`. 
This PR fixes that issue.
    
    ### What changes are included in this PR?
    
    Writes the index for the decompressed ArrowBuf.
    
    ### Are these changes tested?
    
    No
    
    ### Are there any user-facing changes?
    
    No
    * Closes: #38725
    
    Lead-authored-by: Vibhatha Lakmal Abeykoon <vibha...@gmail.com>
    Co-authored-by: vibhatha <vibha...@gmail.com>
    Signed-off-by: David Li <li.david...@gmail.com>
---
 .../java/org/apache/arrow/compression/Lz4CompressionCodec.java    | 1 +
 .../java/org/apache/arrow/compression/TestCompressionCodec.java   | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git 
a/java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
 
b/java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
index daa35b7e15..e8b780638e 100644
--- 
a/java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
+++ 
b/java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
@@ -79,6 +79,7 @@ public class Lz4CompressionCodec extends 
AbstractCompressionCodec {
     byte[] outBytes = out.toByteArray();
     ArrowBuf decompressedBuffer = allocator.buffer(outBytes.length);
     decompressedBuffer.setBytes(/*index=*/0, outBytes);
+    decompressedBuffer.writerIndex(decompressedLength);
     return decompressedBuffer;
   }
 
diff --git 
a/java/compression/src/test/java/org/apache/arrow/compression/TestCompressionCodec.java
 
b/java/compression/src/test/java/org/apache/arrow/compression/TestCompressionCodec.java
index 403130edba..01156fa2b0 100644
--- 
a/java/compression/src/test/java/org/apache/arrow/compression/TestCompressionCodec.java
+++ 
b/java/compression/src/test/java/org/apache/arrow/compression/TestCompressionCodec.java
@@ -117,6 +117,12 @@ class TestCompressionCodec {
     return outputBuffers;
   }
 
+  private void assertWriterIndex(List<ArrowBuf> decompressedBuffers) {
+    for (ArrowBuf decompressedBuf : decompressedBuffers) {
+      assertTrue(decompressedBuf.writerIndex() > 0);
+    }
+  }
+
   @ParameterizedTest
   @MethodSource("codecs")
   void testCompressFixedWidthBuffers(int vectorLength, CompressionCodec codec) 
throws Exception {
@@ -139,6 +145,7 @@ class TestCompressionCodec {
     List<ArrowBuf> decompressedBuffers = deCompressBuffers(codec, 
compressedBuffers);
 
     assertEquals(2, decompressedBuffers.size());
+    assertWriterIndex(decompressedBuffers);
 
     // orchestrate new vector
     IntVector newVec = new IntVector("new vec", allocator);
@@ -180,6 +187,7 @@ class TestCompressionCodec {
     List<ArrowBuf> decompressedBuffers = deCompressBuffers(codec, 
compressedBuffers);
 
     assertEquals(3, decompressedBuffers.size());
+    assertWriterIndex(decompressedBuffers);
 
     // orchestrate new vector
     VarCharVector newVec = new VarCharVector("new vec", allocator);