From 65738c1eb37c789294124cc9b4bbe6d55d50a77f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Fri, 20 Oct 2017 14:01:38 +0300
Subject: [PATCH] event: fix datarace between Subscribe and Send
---
event/feed.go | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/event/feed.go b/event/feed.go
index b1b597f17..78fa3d98d 100644
--- a/event/feed.go
+++ b/event/feed.go
@@ -127,6 +127,8 @@ func (f *Feed) remove(sub *feedSub) {
// Send delivers to all subscribed channels simultaneously.
// It returns the number of subscribers that the value was sent to.
func (f *Feed) Send(value interface{}) (nsent int) {
+ rvalue := reflect.ValueOf(value)
+
f.once.Do(f.init)
<-f.sendLock
@@ -134,14 +136,14 @@ func (f *Feed) Send(value interface{}) (nsent int) {
f.mu.Lock()
f.sendCases = append(f.sendCases, f.inbox...)
f.inbox = nil
- f.mu.Unlock()
- // Set the sent value on all channels.
- rvalue := reflect.ValueOf(value)
if !f.typecheck(rvalue.Type()) {
f.sendLock <- struct{}{}
panic(feedTypeError{op: "Send", got: rvalue.Type(), want: f.etype})
}
+ f.mu.Unlock()
+
+ // Set the sent value on all channels.
for i := firstSubSendCase; i < len(f.sendCases); i++ {
f.sendCases[i].Send = rvalue
}
--
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