From aae444ac3b8176563de4f4487ba392ed54505ed1 Mon Sep 17 00:00:00 2001
From: Virgil <virgil@lethean.io>
Date: Fri, 3 Apr 2026 08:11:24 +0000
Subject: [PATCH] fix(store): harden event shutdown

Co-Authored-By: Virgil <virgil@lethean.io>
---
 events.go | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/events.go b/events.go
index 7e1438a..80aca8a 100644
--- a/events.go
+++ b/events.go
@@ -82,11 +82,17 @@ func (storeInstance *Store) Watch(group string) <-chan Event {
 	eventChannel := make(chan Event, watcherEventBufferCapacity)
 
 	storeInstance.watchersLock.Lock()
+	defer storeInstance.watchersLock.Unlock()
+	storeInstance.closeLock.Lock()
+	closed = storeInstance.closed
+	storeInstance.closeLock.Unlock()
+	if closed {
+		return closedEventChannel()
+	}
 	if storeInstance.watchers == nil {
 		storeInstance.watchers = make(map[string][]chan Event)
 	}
 	storeInstance.watchers[group] = append(storeInstance.watchers[group], eventChannel)
-	storeInstance.watchersLock.Unlock()
 
 	return eventChannel
 }
@@ -156,8 +162,14 @@ func (storeInstance *Store) OnChange(callback func(Event)) func() {
 	callbackRegistration := changeCallbackRegistration{registrationID: registrationID, callback: callback}
 
 	storeInstance.callbacksLock.Lock()
+	defer storeInstance.callbacksLock.Unlock()
+	storeInstance.closeLock.Lock()
+	closed = storeInstance.closed
+	storeInstance.closeLock.Unlock()
+	if closed {
+		return func() {}
+	}
 	storeInstance.callbacks = append(storeInstance.callbacks, callbackRegistration)
-	storeInstance.callbacksLock.Unlock()
 
 	// Return an idempotent unregister function.
 	var once sync.Once
@@ -194,6 +206,13 @@ func (storeInstance *Store) notify(event Event) {
 	}
 
 	storeInstance.watchersLock.RLock()
+	storeInstance.closeLock.Lock()
+	closed = storeInstance.closed
+	storeInstance.closeLock.Unlock()
+	if closed {
+		storeInstance.watchersLock.RUnlock()
+		return
+	}
 	for _, registeredChannel := range storeInstance.watchers["*"] {
 		select {
 		case registeredChannel <- event: