From 33b3bc6a7ddca2f99683c5c3ee86b24f80a7a075 Mon Sep 17 00:00:00 2001
From: ErickSkrauch <erickskrauch@yandex.ru>
Date: Mon, 30 Mar 2020 14:53:01 +0300
Subject: [PATCH] Allow call Publish with nil values

---
 event_bus.go      | 19 ++++++++++++-------
 event_bus_test.go | 10 +++++++---
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/event_bus.go b/event_bus.go
index d4cf80f..9e66b8a 100644
--- a/event_bus.go
+++ b/event_bus.go
@@ -45,7 +45,7 @@ type eventHandler struct {
 	flagOnce      bool
 	async         bool
 	transactional bool
-	sync.Mutex // lock for an event handler - useful for running async callbacks serially
+	sync.Mutex    // lock for an event handler - useful for running async callbacks serially
 }
 
 // New returns new EventBus with empty handlers.
@@ -154,7 +154,7 @@ func (bus *EventBus) Publish(topic string, args ...interface{}) {
 }
 
 func (bus *EventBus) doPublish(handler *eventHandler, topic string, args ...interface{}) {
-	passedArguments := bus.setUpPublish(topic, args...)
+	passedArguments := bus.setUpPublish(handler, args...)
 	handler.callBack.Call(passedArguments)
 }
 
@@ -192,12 +192,17 @@ func (bus *EventBus) findHandlerIdx(topic string, callback reflect.Value) int {
 	return -1
 }
 
-func (bus *EventBus) setUpPublish(topic string, args ...interface{}) []reflect.Value {
-
-	passedArguments := make([]reflect.Value, 0)
-	for _, arg := range args {
-		passedArguments = append(passedArguments, reflect.ValueOf(arg))
+func (bus *EventBus) setUpPublish(callback *eventHandler, args ...interface{}) []reflect.Value {
+	funcType := callback.callBack.Type()
+	passedArguments := make([]reflect.Value, len(args))
+	for i, v := range args {
+		if v == nil {
+			passedArguments[i] = reflect.New(funcType.In(i)).Elem()
+		} else {
+			passedArguments[i] = reflect.ValueOf(v)
+		}
 	}
+
 	return passedArguments
 }
 
diff --git a/event_bus_test.go b/event_bus_test.go
index 0cf196d..e89a0bc 100644
--- a/event_bus_test.go
+++ b/event_bus_test.go
@@ -73,12 +73,16 @@ func TestUnsubscribe(t *testing.T) {
 
 func TestPublish(t *testing.T) {
 	bus := New()
-	bus.Subscribe("topic", func(a int, b int) {
-		if a != b {
+	bus.Subscribe("topic", func(a int, err error) {
+		if a != 10 {
+			t.Fail()
+		}
+
+		if err != nil {
 			t.Fail()
 		}
 	})
-	bus.Publish("topic", 10, 10)
+	bus.Publish("topic", 10, nil)
 }
 
 func TestSubcribeOnceAsync(t *testing.T) {