net/http: enhanced ServerMux routing

[kassner]

Go version

go1.22rc1

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='/home/kassner/.cache/go-build'
GOENV='/home/kassner/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/kassner/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/kassner/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/kassner/sdk/go1.22rc1'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/kassner/sdk/go1.22rc1/pkg/tool/linux_arm64'
GOVCS=''
GOVERSION='go1.22rc1'
GCCGO='gccgo'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/kassner/workspace/go122test/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1457264763=/tmp/go-build -gno-record-gcc-switches'

What did you do?

package main

import (
	"fmt"
	"io"
	"net/http"
	"sync"
	"time"
)

func main() {
	handler := http.NewServeMux()
	handler.HandleFunc("GET /", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(r.URL.Path))
	})

	go http.ListenAndServe(":9090", handler)

	wg := sync.WaitGroup{}
	wg.Add(1)

	go func() {
		defer wg.Done()
		time.Sleep(time.Second)

		resp, err := http.Get("http://localhost:9090/")
		if err != nil {
			panic(err)
		}

		body, _ := io.ReadAll(resp.Body)
		if err != nil {
			panic(err)
		}

		fmt.Println("statusCode:", resp.StatusCode)
		fmt.Println("body:", string(body))
	}()

	wg.Wait()
}

What did you see happen?

statusCode: 404
body: 404 page not found

What did you expect to see?

statusCode: 200
body: /

[kassner]

Nevermind, I just needed that public shaming adrenaline rush to figure it out:

kassner@raspberrypi:~/workspace/go122test $ cat go.mod 
module test

go 1.21
kassner@raspberrypi:~/workspace/go122test $ ~/go/bin/go1.22rc1 run main.go 
statusCode: 404
body: 404 page not found

kassner@raspberrypi:~/workspace/go122test $ cat go.mod 
module test

go 1.22rc1
kassner@raspberrypi:~/workspace/go122test $ ~/go/bin/go1.22rc1 run main.go 
statusCode: 200
body: /

[jub0bs]

A detail, but shouldn't this issue be renamed

net/http: enhanced ServeMux routing

(ServeMux, not ServerMux) ?