From ad8c97c9bb24027349f9f7c3ab20f550cc2a3159 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Tue, 2 Nov 2021 18:50:41 -0400
Subject: [PATCH] CHATHISTORY with nonexistent msgid should send empty batch

It was sending MESSAGE_ERROR, which was inappropriate. Send an empty batch
for now (this is at parity with the in-memory implementation).
---
 irc/mysql/history.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/irc/mysql/history.go b/irc/mysql/history.go
index 8d78291e..39a13697 100644
--- a/irc/mysql/history.go
+++ b/irc/mysql/history.go
@@ -1043,14 +1043,22 @@ func (s *mySQLHistorySequence) Between(start, end history.Selector, limit int) (
 	if start.Msgid != "" {
 		startTime, _, _, err = s.mysql.lookupMsgid(ctx, start.Msgid, false)
 		if err != nil {
-			return nil, err
+			if err == sql.ErrNoRows {
+				return nil, nil
+			} else {
+				return nil, err
+			}
 		}
 	}
 	endTime := end.Time
 	if end.Msgid != "" {
 		endTime, _, _, err = s.mysql.lookupMsgid(ctx, end.Msgid, false)
 		if err != nil {
-			return nil, err
+			if err == sql.ErrNoRows {
+				return nil, nil
+			} else {
+				return nil, err
+			}
 		}
 	}