v3: Improve and simplify logic of ctx.Next() (#3063)

* Simplify Next() handler in Ctx

* Add comments

ctx.go

@@ -1023,19 +1023,20 @@ func (c *DefaultCtx) ClientHelloInfo() *tls.ClientHelloInfo {
 func (c *DefaultCtx) Next() error {
 	// Increment handler index
 	c.indexHandler++
-	var err error
+
 	// Did we execute all route handlers?
 	if c.indexHandler < len(c.route.Handlers) {
 		// Continue route stack
-		err = c.route.Handlers[c.indexHandler](c)
+		return c.route.Handlers[c.indexHandler](c)
-	} else {
+	}
+
 	// Continue handler stack
 	if c.app.newCtxFunc != nil {
-			_, err = c.app.nextCustom(c)
+		_, err := c.app.nextCustom(c)
-		} else {
+		return err
-			_, err = c.app.next(c)
-		}
 	}
+
+	_, err := c.app.next(c)
 	return err
 }
 

router_test.go

@@ -542,6 +542,27 @@ func Benchmark_Router_Next(b *testing.B) {
 	require.Equal(b, 4, c.indexRoute)
 }
 
+// go test -v ./... -run=^$ -bench=Benchmark_Router_Next_Default -benchmem -count=4
+func Benchmark_Router_Next_Default(b *testing.B) {
+	app := New()
+	app.Get("/", func(_ Ctx) error {
+		return nil
+	})
+
+	h := app.Handler()
+
+	fctx := &fasthttp.RequestCtx{}
+	fctx.Request.Header.SetMethod(MethodGet)
+	fctx.Request.SetRequestURI("/")
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for n := 0; n < b.N; n++ {
+		h(fctx)
+	}
+}
+
 // go test -v ./... -run=^$ -bench=Benchmark_Route_Match -benchmem -count=4
 func Benchmark_Route_Match(b *testing.B) {
 	var match bool