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On March 15, the official version of go 1.18 was released to learn about the latest features and usage

2022-07-06 12:50:00 【Deng Jiawen jarvan】

3 month 15 Number Go 1.18 Official release Learn about the latest features and usage

linux Download and install go1.18

(1) download

curl -o go1.18.linux-amd64.tar.gz  https://dl.google.com/go/go1.18.linux-amd64.tar.gz

(2) new go Version folder

( Here you can replace it with the directory you want )

mkdir ~/go1.18

(3) Unzip the file to the new version folder

( Here you can replace it with the directory you want )

tar zxvf go1.18.linux-amd64.tar.gz -C ~/go1.18

(4) Modify the environment variable to the new version

vim /etc/profile

# root directory ( Here you can replace it with the directory you want )
export GOROOT=$HOME/go1.18
#bin Catalog 
export GOBIN=$GOROOT/bin
# working directory 
export GOPATH=/root/src.go
export PATH=$PATH:$GOPATH:$GOBIN:$GOROOT

(5) Refresh the environment variable configuration

source /etc/profile

(6) see go edition

$ go version
go version go1.18 linux/amd64

The update is successful

Possible problems 1: Environment variables are reset after reconnection

bash Configure the environment variable to ~/.profile perhaps ~/.bash_profile

zsh Configure the environment variables ~/.zshrc

Because reopening the terminal will automatically execute them

(7) vscode Need to be reinstalled go tools

In general use vscode + ssh Remote development

go After the version is updated, the original go tools It may not be available , We need to re install go tools

Click Settings ->command-pallet…( Command Panel )-> Input go tools -> Choose all -> update

Generic generic

Generic small case : Multiple types of support hashmap

func Test Generic generic(t *testing.T) {
    
	//[string,string]  Type of  hashmap
	hashmap1 := &HashMap[string, string]{
    hashmap: make(map[string]string)}
	hashmap1.Set("k1", "v1")
	value, _ := hashmap1.Get("k1")
	fmt.Printf("value2: %v,type=%T\n", value, value)
	//[string,int]  Type of  hashmap
	hashmap2 := &HashMap[string, int]{
    hashmap: make(map[string]int)}
	hashmap2.Set("k1", 1)
	value2, _ := hashmap2.Get("k1")
	fmt.Printf("value2: %v,type=%T\n", value2, value2)
	// value2: v1,type=string
	// value2: 1,type=int
}

type HashMap[K comparable, V any] struct {
    
	hashmap map[K]V
}

func (h *HashMap[K, V]) Set(key K, value V) {
    
	h.hashmap[key] = value
}
func (h *HashMap[K, V]) Get(key K) (value V, ok bool) {
    
	value, ok = h.hashmap[key]
	return value, ok
}

Fuzzy testing fuzzing

fuzzing testing The design of fuzzy tests, like generics, has existed for a long time
fuzzing testing Fuzzy testing / Random testing will test the reliability of software randomly or according to the initial data of developers and continuously
go test The current members of the tool chain are : unit testing test、 Performance benchmarking bench, Fuzzy testing fuzzing

Fuzzy test case

package main

import (
	"fmt"
	"testing"
	"unicode/utf8"

	"github.com/stretchr/testify/assert"
)

// String inversion function ( To be tested )
func Reverse(s string) string {
    
	b := []byte(s)
	for i, j := 0, len(b)-1; i < len(b)/2; i, j = i+1, j-1 {
    
		b[i], b[j] = b[j], b[i]
	}
	return string(b)
}

// General unit testing 
func TestReverse(t *testing.T) {
    
	testcases := []struct {
    
		in, expect string
	}{
    
		{
    "Hello, world", "dlrow ,olleH"},
		{
    " ", " "},
		{
    "!12345", "54321!"},
	}
	for _, tc := range testcases {
    
		actual := Reverse(tc.in)
		assert.Equal(t, tc.expect, actual)
	}
}

// Fuzzy testing , And unit testing complement each other 
// go test -fuzz=Fuzz -run ^FuzzReverse$ -v
// Will generate  testdata  There are crash test data ,Fial The data of 
func FuzzReverse(f *testing.F) {
    
	testcases := []string{
    "Hello, world", " ", "!12345"}
	for _, tc := range testcases {
    
		f.Add(tc) // Use f.Add to provide a seed corpus
	}
	f.Fuzz(func(t *testing.T, orig string) {
    
		fmt.Printf(".")
		rev := Reverse(orig)
		doubleRev := Reverse(rev)
		if orig != doubleRev {
    
			t.Errorf("Before: %q, after: %q", orig, doubleRev)
		}
		if utf8.ValidString(orig) && !utf8.ValidString(rev) {
    
			t.Errorf("Reverse produced invalid UTF-8 string %q", rev)
		}
	})
}

work area workspace

for instance

I want to update a tool module tools, And see the effect of this module update in the project , The general practice is to modify go.mod file , Use replace github Upper tool Replace the library to its local directory , Then the effect of local modification can be reflected in the project in real time
After the module is modified successfully , If this project does not go.mod If you change it back, you must have failed to compile
Workspace mode workspace Can be in go.mod The parent directory of encapsulates a layer of independent go.work, In this document replace Replace , Do not modify the original project go.mod file

Example workspace

The project directory is as follows

workspace-demo
├── project
│   ├── go.mod      //  Project modules ,mod Sub module 
│   └── main.go
├── go.work         //  work area ,work Upper module 
└── tools
    ├── fish.go
    └── go.mod      //  Tool module ,mod Sub module

Initialize workspace

#  Create a new workspace folder 
mkdir workspace-demo
cd workspace-demo
#  Cloning project  project  And developed modules  tools,  For reference only , Please replace with the appropriate  git  Warehouse 
git clone https://github.com/me/project
git clone https://github.com/me/tools
#  Initialize workspace 
go work init ./project ./tools

modify go.work also replace long-range tools Module to local

go 1.18

use (
        ./project
        ./tools
)
// Modify the remote module to replace it locally 
replace github.com/me/tools => ./tools

Performance improvement

Apple M1、ARM64 and PowerPC64 Users will be delighted ! because Go 1.17 The register of ABI Calling convention Extend to these architectures ,Go 1.18 Of CPU Performance improvements of up to 20%. To emphasize the performance improvement of this version , We will 20% Performance improvement of As the fourth most important title

About 1.18 A more detailed description of everything in , Please refer to Go 1.18 Release notes .