Data race

[jhaynie]

When you build/run with -race you'll get the following stack using any of the basic examples:

==================
WARNING: DATA RACE
Write at 0x00c420311640 by goroutine 32:
  github.com/manifoldco/promptui.(*Prompt).Run.func2()
      /Users/jhaynie/go/src/github.com/manifoldco/promptui/prompt.go:136 +0xa7b
  github.com/chzyer/readline.(*DumpListener).OnChange()
      /Users/jhaynie/go/src/github.com/chzyer/readline/operation.go:516 +0x96
  github.com/chzyer/readline.(*Operation).ioloop()
      /Users/jhaynie/go/src/github.com/chzyer/readline/operation.go:339 +0x771

Previous read at 0x00c420311640 by main goroutine:
  github.com/manifoldco/promptui.(*Prompt).Run()
      /Users/jhaynie/go/src/github.com/manifoldco/promptui/prompt.go:194 +0x77a
  github.com/pinpt/worker/cmd/customer.glob..func12()
      /Users/jhaynie/go/src/github.com/pinpt/worker/cmd/customer/enroll.go:33 +0x118
  github.com/pinpt/worker/vendor/github.com/spf13/cobra.(*Command).execute()
      /Users/jhaynie/go/src/github.com/pinpt/worker/vendor/github.com/spf13/cobra/command.go:702 +0x8ac
  github.com/pinpt/worker/vendor/github.com/spf13/cobra.(*Command).ExecuteC()
      /Users/jhaynie/go/src/github.com/pinpt/worker/vendor/github.com/spf13/cobra/command.go:783 +0x444
  github.com/pinpt/worker/vendor/github.com/spf13/cobra.(*Command).Execute()
      /Users/jhaynie/go/src/github.com/pinpt/worker/vendor/github.com/spf13/cobra/command.go:736 +0x38
  github.com/pinpt/worker/cmd.Execute()
      /Users/jhaynie/go/src/github.com/pinpt/worker/cmd/root.go:148 +0xec
  main.main()
      /Users/jhaynie/go/src/github.com/pinpt/worker/main.go:8 +0x2f

since promptui is reading and writing on 2 different goroutines ... probably should switch to either using a mutex (or ideally a channel)

For completeness of issue, here's the code:

prompt := promptui.Prompt{
	Label: "Customer Name",
	Validate: func(input string) error {
		if len(input) < 3 {
			return fmt.Errorf("customer name must be at least 3 characters")
		}
		return nil
	},
}
customerName, err := prompt.Run()

[hallazzang]

FYI, on my machine I get:

==================
WARNING: DATA RACE
Read at 0x00c420010160 by main goroutine:
  github.com/manifoldco/promptui.(*Prompt).Run()
      /Users/halla/Documents/Develop/Golang/src/github.com/manifoldco/promptui/prompt.go:197 +0x7b1
  main.main()
      /Users/halla/Develop/Golang/src/github.com/hallazzang/tests/promptui-issue55/main.go:25 +0x112

Previous write at 0x00c420010160 by goroutine 17:
  github.com/manifoldco/promptui.(*Prompt).Run.func2()
      /Users/halla/Documents/Develop/Golang/src/github.com/manifoldco/promptui/prompt.go:139 +0xa7b
  github.com/chzyer/readline.(*DumpListener).OnChange()
      /Users/halla/Documents/Develop/Golang/src/github.com/chzyer/readline/operation.go:516 +0x96
  github.com/chzyer/readline.(*Operation).ioloop()
      /Users/halla/Documents/Develop/Golang/src/github.com/chzyer/readline/operation.go:339 +0x771

Goroutine 17 (running) created at:
  github.com/chzyer/readline.NewOperation()
      /Users/halla/Documents/Develop/Golang/src/github.com/chzyer/readline/operation.go:88 +0x7f6
  github.com/chzyer/readline.(*Terminal).Readline()
      /Users/halla/Documents/Develop/Golang/src/github.com/chzyer/readline/terminal.go:95 +0x53
  github.com/chzyer/readline.NewEx()
      /Users/halla/Documents/Develop/Golang/src/github.com/chzyer/readline/readline.go:167 +0x62
  github.com/manifoldco/promptui.(*Prompt).Run()
      /Users/halla/Documents/Develop/Golang/src/github.com/manifoldco/promptui/prompt.go:114 +0x1e9
  main.main()
      /Users/halla/Develop/Golang/src/github.com/hallazzang/tests/promptui-issue55/main.go:25 +0x112

When I run the basic example using following commands:

$ go build -race main.go  # In this step, there's no output
$ go run -race main.go  # It spits out the message above