From e6bb8a46c48e80d4e69c2535f8095f5ba1d976a0 Mon Sep 17 00:00:00 2001
From: Luke <lugehorsam@gmail.com>
Date: Thu, 6 May 2021 09:12:05 -0400
Subject: [PATCH] fix off-by-one error in indexing leaderboard records around
 owner (#605)

* calculate start and end of leaderboard record slice from owner pivot

* use more consistent terminology in slice comments

* simplify leaderboard around owner algorithm
---
 server/core_leaderboard.go | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/server/core_leaderboard.go b/server/core_leaderboard.go
index 7fc251432..cd32e966f 100644
--- a/server/core_leaderboard.go
+++ b/server/core_leaderboard.go
@@ -628,12 +628,17 @@ func getLeaderboardRecordsHaystack(ctx context.Context, logger *zap.Logger, db *
 	records := append(firstRecords, ownerRecord)
 	records = append(records, secondRecords...)
 
-	start := len(records) - int(limit)
-	if start < 0 {
+	numRecords := len(records)
+	start := numRecords - int(limit)
+	if len(firstRecords) < limit/2 {
 		start = 0
 	}
+	end := start + int(limit)
+	if end > numRecords {
+		end = numRecords
+	}
 
-	records = records[start:]
+	records = records[start:end]
 	rankCache.Fill(leaderboardId, expiryTime.Unix(), records)
 
 	return records, nil
-- 
GitLab