From 6e78f379d927271b3e649921388e8dba32c83587 Mon Sep 17 00:00:00 2001
From: Adrien Grand <jpountz@gmail.com>
Date: Wed, 6 Nov 2024 11:34:27 +0100
Subject: [PATCH] Fix TestPostingsUtil#testIntegerOverflow failure. (#13979)

The group vint logic is mistakenly using the long->int conversion logic for the
case when integers are being written rather than longs.

Closes #13978
---
 .../src/java/org/apache/lucene/util/GroupVIntUtil.java |  2 +-
 .../lucene/codecs/lucene101/TestPostingsUtil.java      | 10 +++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/util/GroupVIntUtil.java b/lucene/core/src/java/org/apache/lucene/util/GroupVIntUtil.java
index 949292fd9d2..e95e2eee4db 100644
--- a/lucene/core/src/java/org/apache/lucene/util/GroupVIntUtil.java
+++ b/lucene/core/src/java/org/apache/lucene/util/GroupVIntUtil.java
@@ -292,7 +292,7 @@ public final class GroupVIntUtil {
 
     // tail vints
     for (; readPos < limit; readPos++) {
-      out.writeVInt(toInt(values[readPos]));
+      out.writeVInt(values[readPos]);
     }
   }
 }
diff --git a/lucene/core/src/test/org/apache/lucene/codecs/lucene101/TestPostingsUtil.java b/lucene/core/src/test/org/apache/lucene/codecs/lucene101/TestPostingsUtil.java
index 41bb5c01f07..5d02d0561e3 100644
--- a/lucene/core/src/test/org/apache/lucene/codecs/lucene101/TestPostingsUtil.java
+++ b/lucene/core/src/test/org/apache/lucene/codecs/lucene101/TestPostingsUtil.java
@@ -27,7 +27,15 @@ public class TestPostingsUtil extends LuceneTestCase {
 
   // checks for bug described in https://github.com/apache/lucene/issues/13373
   public void testIntegerOverflow() throws IOException {
-    final int size = random().nextInt(1, ForUtil.BLOCK_SIZE);
+    // Size that writes the first value as a regular vint
+    int randomSize1 = random().nextInt(1, 3);
+    // Size that writes the first value as a group vint
+    int randomSize2 = random().nextInt(4, ForUtil.BLOCK_SIZE);
+    doTestIntegerOverflow(randomSize1);
+    doTestIntegerOverflow(randomSize2);
+  }
+
+  private void doTestIntegerOverflow(int size) throws IOException {
     final int[] docDeltaBuffer = new int[size];
     final int[] freqBuffer = new int[size];