From 6c206b8010920269c1416792dd4e118ff9ad714f Mon Sep 17 00:00:00 2001
From: James Shubin <james@shubin.ca>
Date: Sat, 23 Aug 2025 16:13:03 -0400
Subject: [PATCH] util: Prevent unlikely race on easy exit

Race detector hit this up once, and I can see how it would be possible.
---
 util/sync.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/util/sync.go b/util/sync.go
index 11f52763..3a45d571 100644
--- a/util/sync.go
+++ b/util/sync.go
@@ -138,7 +138,7 @@ func (obj *EasyExit) Done(err error) {
 	}
 	if err != nil {
 		// TODO: we could add a mutex, and turn this into a multierr
-		obj.err = err
+		obj.err = err // use the mutex to prevent a race on this write
 	}
 	obj.once.Do(func() { close(obj.exit) })
 }
@@ -173,7 +173,9 @@ func (obj *EasyExit) Error() error {
 	case <-obj.exit:
 	}
 	obj.wg.Wait() // wait for cleanup
-	return obj.err
+	obj.mutex.Lock()
+	defer obj.mutex.Unlock()
+	return obj.err // use the mutex to prevent a race on this read
 }
 
 // SubscribedSignal represents a synchronized read signal. It doesn't need to be