[events] Fix race condition and missing unlock of mutex (#2453)

v2/internal/frontend/runtime/events.go

@@ -69,6 +69,7 @@ func (e *Events) OffAll() {
 	for eventName := range e.listeners {
 		delete(e.listeners, eventName)
 	}
+	e.notifyLock.Unlock()
 }
 
 // NewEvents creates a new log subsystem
@@ -115,6 +116,8 @@ func (e *Events) unRegisterListener(eventName string) {
 
 // Notify backend for the given event name
 func (e *Events) notifyBackend(eventName string, data ...interface{}) {
+	e.notifyLock.Lock()
+	defer e.notifyLock.Unlock()
 
 	// Get list of event listeners
 	listeners := e.listeners[eventName]
@@ -123,9 +126,6 @@ func (e *Events) notifyBackend(eventName string, data ...interface{}) {
 		return
 	}
 
-	// Lock the listeners
-	e.notifyLock.Lock()
-
 	// We have a dirty flag to indicate that there are items to delete
 	itemsToDelete := false
 
@@ -163,9 +163,6 @@ func (e *Events) notifyBackend(eventName string, data ...interface{}) {
 			delete(e.listeners, eventName)
 		}
 	}
-
-	// Unlock
-	e.notifyLock.Unlock()
 }
 
 func (e *Events) AddFrontend(appFrontend frontend.Frontend) {

website/src/pages/changelog.mdx

@@ -39,6 +39,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed `undo`/`redo` on macOS. Fixed by @stffabi in [PR](https://github.com/wailsapp/wails/pull/2430)
 - Fixed `Events*` runtime functions in JavaScript not returning the function to cancel the watcher. Fixed by @zllovesuki in [PR](https://github.com/wailsapp/wails/pull/2434)
 - Fixed AppOptions merging defaults when a custom logger is used. Fixed by @stffabi in [PR](https://github.com/wailsapp/wails/pull/2452)
+- Fixed race condition and missing unlock of mutex in events handling. Fixed by @stffabi in [PR](https://github.com/wailsapp/wails/pull/2453)
 
 ## v2.3.0 - 2022-12-29