From 5b1a34bddd9a2bab16858d66e93f04af6500eb6b Mon Sep 17 00:00:00 2001
From: Adrien Grand <jpountz@gmail.com>
Date: Tue, 21 May 2024 11:51:59 +0200
Subject: [PATCH] Fix max score computation in BlockMaxConjunctionBulkScorer.
 (#13397)

It sums up max scores in a float when it should sum them up in a double like we
do for `Scorer#score()`. Otherwise, max scores may be returned that are less
than actual scores.

This bug was introduced in #13343, so it is not released yet.

Closes #13371
Closes #13396
---
 .../apache/lucene/search/BlockMaxConjunctionBulkScorer.java   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lucene/core/src/java/org/apache/lucene/search/BlockMaxConjunctionBulkScorer.java b/lucene/core/src/java/org/apache/lucene/search/BlockMaxConjunctionBulkScorer.java
index aa276d277be..9f4531540a5 100644
--- a/lucene/core/src/java/org/apache/lucene/search/BlockMaxConjunctionBulkScorer.java
+++ b/lucene/core/src/java/org/apache/lucene/search/BlockMaxConjunctionBulkScorer.java
@@ -67,7 +67,7 @@ final class BlockMaxConjunctionBulkScorer extends BulkScorer {
       scorers[i].advanceShallow(windowMin);
     }
 
-    float maxWindowScore = 0;
+    double maxWindowScore = 0;
     for (int i = 0; i < scorers.length; ++i) {
       float maxClauseScore = scorers[i].getMaxScore(windowMax);
       sumOfOtherClauses[i] = maxClauseScore;
@@ -76,7 +76,7 @@ final class BlockMaxConjunctionBulkScorer extends BulkScorer {
     for (int i = sumOfOtherClauses.length - 2; i >= 0; --i) {
       sumOfOtherClauses[i] += sumOfOtherClauses[i + 1];
     }
-    return maxWindowScore;
+    return (float) maxWindowScore;
   }
 
   @Override