Re: [PATCH 0/6] echo usernames as they are typed

> On Mon, Nov 28, 2011 at 10:36:21AM +0100, Erik Faye-Lund wrote:
>
>> > You really want to open "/dev/tty" on most Unix systems (which is what
>> > getpass() does).
>>
>> Yes, you're right. Opening "/dev/tty" is much better. But what happens
>> for processes started by GUI applications (with no easily observable
>> tty, if any)? Does open simply fail? If so, is it desirable for us to
>> fail in that case?
>
> Yes, the open will fail (on Linux, I get ENXIO).
>
> And yes, we should fail in that case. getpass() will generally return
> NULL in that instance, and the current implementation of git_getpass()
> will die(), explaining that we could not get the password.
>
>> > I have no idea what would be appropriate on Windows.
>>
>> It's pretty similar, but not exactly: CreateFile("CONIN$", ...) or
>> CreateFile("CONOUT$", ...), depending on if you want the read-handle
>> or the write-handle... I can probably cook up something a bit more
>> concrete, though.
>
> OK, that maps to the /dev/tty concept quite well. Though I suspect the
> code for turning off character echo-ing is going to also be different.
>
>> But _getch() that we already use always reads from the console
>> (according to MSDN, I haven't actually tested this myself:
>> http://msdn.microsoft.com/en-us/library/078sfkak%28v=VS.80%29.aspx).
>> But I don't think this allows us to fail when no console is attached.
>> Question is, should we fail in such cases? Windows does have an API to
>> prompt for passwords in a GUI window... Perhaps fallbacking to those
>> are the way to go? Something like:
>>
>> if (GetConsoleWindow()) {
>>       /*  normal console-stuff */
>> } else {
>>       /* call CredUIPromptForWindowsCredentials(...) instead */
>> }
>
> Certainly on non-Windows something like that would not be welcome. The
> user can already have specified GIT_ASKPASS if they don't have a
> terminal. And once the credential-helper code is in, they can use a
> platform-specific helper that provides a nice dialog if they want it.
>