copywaitgroup

copywaitgroup

copywaitgroup finds a func that passes sync.WaitGroup as a value instead of a pointer

Instruction

go install github.com/sivchari/copywaitgroup/cmd/copywaitgroup

Usage

package main

import (
	"sync"
)

var globalWait sync.WaitGroup

func g(wg sync.WaitGroup) {
	wg.Done()
}

func pg(wg *sync.WaitGroup) {
	wg.Done()
}

func main() {
	{
		var wg sync.WaitGroup
		a := 1

		wg.Add(1)
		go func(a int, wg sync.WaitGroup) { // want "`wg` of arg `2` is passed as a value. you must pass as a pointer. the goroutine will be deadlock!"
			println(a)
			wg.Done()
		}(a, wg)
		wg.Wait()

		wg.Add(1)
		go func(a int, wg *sync.WaitGroup) { // ok
			println(a)
			wg.Done()
		}(a, &wg)
		wg.Wait()

		wg.Add(1)
		go func() { // ok
			wg.Done()
		}()
		wg.Wait()
	}

	{
		var wg sync.WaitGroup
		wg.Add(2)
		go g(wg)   // want "`wg` of arg `1` is passed as a value. you must pass as a pointer. the goroutine will be deadlock!"
		go pg(&wg) // ok
		wg.Wait()
	}

	{
		go g(globalWait) // ok
	}
}

fish

go vet -vettool=(which copywaitgroup) ./...

./main.go:23:3: `wg` of arg `2` is passed as a value. you must pass as a pointer. the goroutine will be deadlock!
./main.go:40:3: `wg` of arg `1` is passed as a value. you must pass as a pointer. the goroutine will be deadlock!

bash

$ go vet -vettool=`which copywaitgroup` ./...

./main.go:23:3: `wg` of arg `2` is passed as a value. you must pass as a pointer. the goroutine will be deadlock!
./main.go:40:3: `wg` of arg `1` is passed as a value. you must pass as a pointer. the goroutine will be deadlock!

CI

CircleCI

- run:
    name: Install copywaitgroup
    command: go get github.com/sivchari/copywaitgroup

- run:
    name: Run copywaitgroup
    command: go vet -vettool=`which copywaitgroup` ./...

GitHub Actions

- name: Install copywaitgroup
  run: go get github.com/sivchari/copywaitgroup

- name: Run copywaitgroup
  run: go vet -vettool=`which copywaitgroup` ./...