Confirm with AskOne panics on command with yes piping

[renta]

What operating system and terminal are you using? Linux

An example that showcases the bug. Simple yes piping lead to a panic for survey.Confirm and survey.AskOne code. I have a cli-command which is asking yes-no on action confirmation. This is the code:

confirm := false
prompt := &survey.Confirm{
    Message: fmt.Sprintf("Do you want to cancel this number %d of events?", eventsNum),
}
if confirmErr := survey.AskOne(prompt, &confirm); confirmErr != nil {
    return fmt.Errorf("error on asking for the confirm: %w", confirmErr)
}
if !confirm {
    return nil
}

It works well with an interactive input when I type yes or no. Bet when I use predefined answer like:

yes | my-fancy-command with --options=value
yes yes | my-fancy-command with --options=value
echo yes | my-fancy-command with --options=value

What did you expect to see? Next execution output of the command.

What did you see instead? I see panic. Top part of the stack:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x7aabea]

goroutine 1 [running]:
github.com/AlecAivazis/survey/v2/terminal.(*RuneReader).ReadLineWithDefault.func2(...)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/terminal/runereader.go:65
github.com/AlecAivazis/survey/v2/terminal.(*RuneReader).ReadLineWithDefault(0xc000292ab0, 0x0, 0x176b1d0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x40, 0x7f9871d175b8, ...)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/terminal/runereader.go:321 +0xf0a
github.com/AlecAivazis/survey/v2/terminal.(*RuneReader).ReadLine(...)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/terminal/runereader.go:37
github.com/AlecAivazis/survey/v2.(*Confirm).getBool(0xc000168b00, 0x1040d00, 0xc000388888, 0xf64b00, 0x0, 0x0)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/confirm.go:57 +0x191
github.com/AlecAivazis/survey/v2.(*Confirm).Prompt(0xc000168b00, 0xc000388888, 0xc00000e010, 0x112c8f0, 0xc00000e018, 0x1125180)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/confirm.go:136 +0x16d
github.com/AlecAivazis/survey/v2.Ask(0xc0001a5bf0, 0x1, 0x1, 0xe6fde0, 0xc00039844a, 0x0, 0x0, 0x0, 0x0, 0x0)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/survey.go:306 +0x57b
github.com/AlecAivazis/survey/v2.AskOne(...)
    /go/pkg/mod/github.com/!alec!aivazis/survey/v2@v2.2.14/survey.go:249
main.glob..func1(0x172f260, 0xc0003d21e0, 0x0, 0x1, 0x0, 0x0)

[mislav]

Thank you for reporting. Survey was not designed to take input from a stream that's not connected to a terminal, but I agree that we should avoid a panic and instead throw a more informative error message. Better yet, maybe Survey could work with any standard input stream, even if it's not a terminal.

To avoid this in your app for now, you should check whether os.Stdin is a terminal, and avoid invoking Survey otherwise.

[gunta]

+1

Getting the same error when running a command that uses survey, running from the shell of http://github.com/google/zx

Zx is not a real terminal