From 5adefb3e88d5f2a9e7139484b0dd5acb8c224e00 Mon Sep 17 00:00:00 2001
From: "yuxuan.wang1" <yuxuan.wang1@bytedance.com>
Date: Mon, 3 Nov 2025 11:15:27 +0800
Subject: [PATCH] optimize: add default NoRoute and NoMethod handles to assist
 troubleshooting

---
 pkg/route/engine.go      | 18 ++++++++++++++++++
 pkg/route/engine_test.go | 18 ++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/pkg/route/engine.go b/pkg/route/engine.go
index 7dfe043fa..849e4eb58 100644
--- a/pkg/route/engine.go
+++ b/pkg/route/engine.go
@@ -402,6 +402,16 @@ func (engine *Engine) Init() error {
 		engine.options.TLS.NextProtos = append(engine.options.TLS.NextProtos, suite.HTTP1)
 	}
 
+	if len(engine.noRoute) <= 0 {
+		engine.noRoute = []app.HandlerFunc{hertzRouteNotFound}
+		engine.rebuild404Handlers()
+	}
+
+	if len(engine.noMethod) <= 0 {
+		engine.noMethod = []app.HandlerFunc{hertzNotAllowedMethod}
+		engine.rebuild405Handlers()
+	}
+
 	if !atomic.CompareAndSwapUint32(&engine.status, 0, statusInitialized) {
 		return errInitFailed
 	}
@@ -417,6 +427,14 @@ func (engine *Engine) listenAndServe() error {
 	return engine.transport.ListenAndServe(engine.onData)
 }
 
+// hertzRouteNotFound is default NoRoute handler when users do not configure any handler with NoRoute.
+// it is not an anonymous function, so utils.NameOfFunction could obtain a specific function name to assist troubleshooting.
+func hertzRouteNotFound(c context.Context, ctx *app.RequestContext) {}
+
+// hertzNotAllowedMethod is default NoMethod handler when users do not configure any handler with NoMethod.
+// it is not an anonymous function, so utils.NameOfFunction could obtain a specific function name to assist troubleshooting.
+func hertzNotAllowedMethod(c context.Context, ctx *app.RequestContext) {}
+
 func (c *hijackConn) Close() error {
 	if !c.e.KeepHijackedConns {
 		// when we do not keep hijacked connections,
diff --git a/pkg/route/engine_test.go b/pkg/route/engine_test.go
index 172209a3f..956a07b95 100644
--- a/pkg/route/engine_test.go
+++ b/pkg/route/engine_test.go
@@ -49,6 +49,7 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -62,6 +63,7 @@ import (
 	errs "github.com/cloudwego/hertz/pkg/common/errors"
 	"github.com/cloudwego/hertz/pkg/common/test/assert"
 	"github.com/cloudwego/hertz/pkg/common/test/mock"
+	"github.com/cloudwego/hertz/pkg/common/utils"
 	"github.com/cloudwego/hertz/pkg/network"
 	"github.com/cloudwego/hertz/pkg/network/standard"
 	"github.com/cloudwego/hertz/pkg/protocol"
@@ -517,6 +519,22 @@ func TestSetEngineRun(t *testing.T) {
 	assert.True(t, e.IsRunning())
 }
 
+func TestEngine_InitNoRouteAndNoMethod(t *testing.T) {
+	e := NewEngine(config.NewOptions(nil))
+	err := e.Init()
+	assert.Assert(t, err == nil, err)
+	assert.Assert(t, len(e.allNoRoute) == 1, e.allNoRoute)
+	hdlName := utils.NameOfFunction(e.allNoRoute[0])
+	pos := strings.LastIndexByte(hdlName, '.')
+	assert.Assert(t, pos >= 0, hdlName)
+	assert.Assert(t, hdlName[pos+1:] == "hertzRouteNotFound", hdlName)
+	assert.Assert(t, len(e.allNoMethod) == 1, e.allNoMethod)
+	hdlName = utils.NameOfFunction(e.allNoMethod[0])
+	pos = strings.LastIndexByte(hdlName, '.')
+	assert.Assert(t, pos >= 0, hdlName)
+	assert.Assert(t, hdlName[pos+1:] == "hertzNotAllowedMethod", hdlName)
+}
+
 type mockConn struct{}
 
 func (m *mockConn) SetWriteTimeout(t time.Duration) error {