在每个循环中使用go例程时，func文字捕获的go vet范围变量

go vet range variable captured by func literal when using go routine inside of for each loop

我不太确定" funcliteral"是什么，因此这个错误使我有些困惑。我想我已经看到了问题-我是从新的go例程中引用一个范围值变量，因此该值可能随时更改，而不是我们期望的值。解决问题的最佳方法是什么？

有问题的代码：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

func (l *Loader) StartAsynchronous() []LoaderProcess {
for _, currentProcess := range l.processes {
cmd := exec.Command(currentProcess.Command, currentProcess.Arguments...)
log.LogMessage("Asynchronously executing LoaderProcess: %+v", currentProcess)
go func() {
output, err := cmd.CombinedOutput()
if err != nil {
log.LogMessage("LoaderProcess exited with error status: %+v\
%v", currentProcess, err.Error())
} else {
log.LogMessage("LoaderProcess exited successfully: %+v", currentProcess)
currentProcess.Log.LogMessage(string(output))
}
time.Sleep(time.Second * TIME_BETWEEN_SUCCESSIVE_ITERATIONS)
}()
}
return l.processes
}

我建议的修正：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

func (l *Loader) StartAsynchronous() []LoaderProcess {
for _, currentProcess := range l.processes {
cmd := exec.Command(currentProcess.Command, currentProcess.Arguments...)
log.LogMessage("Asynchronously executing LoaderProcess: %+v", currentProcess)
localProcess := currentProcess
go func() {
output, err := cmd.CombinedOutput()
if err != nil {
log.LogMessage("LoaderProcess exited with error status: %+v\
%v", localProcess, err.Error())
} else {
log.LogMessage("LoaderProcess exited successfully: %+v", localProcess)
localProcess.Log.LogMessage(string(output))
}
time.Sleep(time.Second * TIME_BETWEEN_SUCCESSIVE_ITERATIONS)
}()
}
return l.processes
}

但这真的可以解决问题吗？我刚刚将引用从范围变量移到了一个不同的局部变量，其值基于我所参与的每个循环的迭代。

别担心，这是Go中新手经常遇到的错误，是的，每个循环都会改变var currentProcess，因此您的goroutine将使用slice l.processes中的最后一个进程，您要做的就是将变量传递为匿名函数的参数，如下所示：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

func (l *Loader) StartAsynchronous() []LoaderProcess {

for ix := range l.processes {

go func(currentProcess *LoaderProcess) {

cmd := exec.Command(currentProcess.Command, currentProcess.Arguments...)
log.LogMessage("Asynchronously executing LoaderProcess: %+v", currentProcess)

output, err := cmd.CombinedOutput()
if err != nil {
log.LogMessage("LoaderProcess exited with error status: %+v\
%v", currentProcess, err.Error())
} else {
log.LogMessage("LoaderProcess exited successfully: %+v", currentProcess)
currentProcess.Log.LogMessage(string(output))
}

time.Sleep(time.Second * TIME_BETWEEN_SUCCESSIVE_ITERATIONS)

}(&l.processes[ix]) // passing the current process using index

}

return l.processes
}