fix(command/cmdbus): track dispatch before publishing event

fix(builtin_test.go): prevent panic on context.Canceled error to avoid unnecessary panic when context is cancelled
fix(handler_test.go): replace context.WithTimeout with context.WithCancel to avoid unnecessary timeout
fix(bus.go): change WithArtificialDelay return type to Option for better type safety

command/builtin/builtin_test.go

@@ -2,6 +2,7 @@ package builtin_test
 
 import (
 	"context"
+	"errors"
 	"testing"
 	"time"
 
@@ -297,7 +298,9 @@ func TestDeleteAggregate_CustomEvent_MatchAll(t *testing.T) {
 
 func panicOn(errs <-chan error) {
 	for err := range errs {
-		panic(err)
+		if !errors.Is(err, context.Canceled) {
+			panic(err)
+		}
 	}
 }
 

command/cmdbus/bus.go

@@ -290,12 +290,6 @@ func (b *Bus[ErrorCode]) Dispatch(ctx context.Context, cmd command.Command, opts
 		Payload:       load,
 	})
 
-	b.debugLog("publishing %q event ...", evt.Name())
-
-	if err := b.bus.Publish(ctx, evt.Any()); err != nil {
-		return fmt.Errorf("publish %q event: %w", evt.Name(), err)
-	}
-
 	out := make(chan error)
 	accepted := make(chan struct{})
 	aborted := make(chan struct{})
@@ -313,6 +307,12 @@ func (b *Bus[ErrorCode]) Dispatch(ctx context.Context, cmd command.Command, opts
 
 	defer b.cleanupDispatch(cmd.ID())
 
+	b.debugLog("publishing %q event ...", evt.Name())
+
+	if err := b.bus.Publish(ctx, evt.Any()); err != nil {
+		return fmt.Errorf("publish %q event: %w", evt.Name(), err)
+	}
+
 	var timeout <-chan time.Time
 	if b.assignTimeout > 0 {
 		timer := time.NewTimer(b.assignTimeout)

command/handler_test.go

@@ -20,10 +20,10 @@ func TestHandler_Handle(t *testing.T) {
 	enc := newEncoder()
 	ebus := eventbus.New()
 	subBus := cmdbus.New[int](enc, ebus)
-	pubBus := cmdbus.New[int](enc, ebus)
+	pubBus := cmdbus.New[int](enc, ebus, cmdbus.AssignTimeout(0))
 	h := command.NewHandler[any](subBus)
 
-	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
 	handled := make(chan command.Command)
@@ -52,9 +52,7 @@ func TestHandler_Handle(t *testing.T) {
 		case err, ok := <-errs:
 			if ok {
 				t.Fatal(err)
-				break
 			}
-			break
 		case h := <-handled:
 			if h.ID() != cmd.ID() || h.Name() != cmd.Name() || !reflect.DeepEqual(h.Payload(), cmd.Payload()) {
 				t.Fatalf("handled Command differs from dispatched Command. want=%v got=%v", cmd, h)

event/eventbus/bus.go

@@ -53,7 +53,7 @@ type Option func(*chanbus)
 // the rate of event publishing. The delay duration is specified by the provided
 // time.Duration value. The function returns an Option that can be used to
 // configure a chanbus instance.
-func WithArtificialDelay(delay time.Duration) func(*chanbus) {
+func WithArtificialDelay(delay time.Duration) Option {
 	return func(c *chanbus) {
 		c.artificialDelay = delay
 	}