From 1bae8af6cd4572302f9347b11433a2732609cf90 Mon Sep 17 00:00:00 2001
From: Emily Casey <emily@atomicjar.com>
Date: Tue, 8 Aug 2023 15:57:19 -0400
Subject: [PATCH] Fixes race condition in EventStream

Locks the mutex for reading when getting Length(). Otherwise, a data race can occur. This can happen despite the previous atomic read because writes are non-atomic.

Signed-off-by: Emily Casey <emily@atomicjar.com>
---
 eventstream/eventstream.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/eventstream/eventstream.go b/eventstream/eventstream.go
index 3487b05f..290337cf 100644
--- a/eventstream/eventstream.go
+++ b/eventstream/eventstream.go
@@ -111,7 +111,9 @@ func (es *EventStream) Publish(evt interface{}) {
 
 // Returns an integer that represents the current number of subscribers to the stream
 func (es *EventStream) Length() int32 {
-	return atomic.LoadInt32(&es.counter)
+	es.RLock()
+	defer es.RUnlock()
+	return es.counter
 }
 
 // Subscription is returned from the Subscribe function.