From ba35a0a96de1c3744ce0ceea83db4337a7252df4 Mon Sep 17 00:00:00 2001
From: Cnly <minecnly@gmail.com>
Date: Tue, 25 Jun 2019 22:45:53 +0800
Subject: [PATCH] Fix nil pointer and goroutine safety in typing cache

Signed-off-by: Alex Chen <minecnly@gmail.com>
---
 typingserver/cache/cache.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/typingserver/cache/cache.go b/typingserver/cache/cache.go
index 831c6f9b3..04de0e822 100644
--- a/typingserver/cache/cache.go
+++ b/typingserver/cache/cache.go
@@ -62,11 +62,12 @@ func (t *TypingCache) GetTypingUsersIfUpdatedAfter(
 	roomID string, position int64,
 ) (users []string, updated bool) {
 	t.RLock()
+	defer t.RUnlock()
+
 	roomData, ok := t.data[roomID]
-	userSet := roomData.userSet
-	t.RUnlock()
 	if ok && roomData.syncPosition > position {
 		updated = true
+		userSet := roomData.userSet
 		users = make([]string, 0, len(userSet))
 		for userID := range userSet {
 			users = append(users, userID)