Re: [PATCH] winansi_isatty(): fix when Git is used from CMD
- From
Johannes Sixt <j6t@kdbg.org>
- Date
- Dec 19, 2016, 19:34 UTC
- Message-ID
- <3f06ea33-b4de-48b4-593e-239eb6e87dd4@kdbg.org>
- In-Reply-To
- <d661dbf1-9852-965a-2ca9-67d763115b9e@kdbg.org>
Am 18.12.2016 um 16:37 schrieb Johannes Sixt:
Show 9 quoted lines
> winansi.c is all about overriding MSVCRT's console handling. If we are > connected to a console, then by the time isatty() is called (from > outside the emulation layer), all handling of file descriptors 1 and 2 > is already outside MSVCRT's control. In particular, we have determined > unambiguously whether a terminal is connected (see is_console()). I > suggest to have the implementation below (on top of the patch I'm > responding to). > > What do you think?
I thought a bit more about this approach, and I retract it. I think it does not work when Git is connected to an MSYS TTY, i.e., when the "console" is in reality the pipe that is detected in detect_msys_tty().
At the same time I wonder how your original winansi_isatty() could have worked: In this case, MSVCRT's isatty() would return 1 (because detect_msys_tty() has set things up that this happens), but then winansi_isatty() checks whether the handle underlying fd 0, 1 or 2 is a real Windows console. But it is not: it is a pipe. Am I missing something?
Show 48 quoted lines
>
> diff --git a/compat/winansi.c b/compat/winansi.c
> index ba360be69b..1748d17777 100644
> --- a/compat/winansi.c
> +++ b/compat/winansi.c
> @@ -575,9 +575,8 @@ static void detect_msys_tty(int fd)
>
> int winansi_isatty(int fd)
> {
> - int res = isatty(fd);
> -
> - if (res) {
> + switch (fd) {
> + case 0:
> /*
> * Make sure that /dev/null is not fooling Git into believing
> * that we are connected to a terminal, as "_isatty() returns a
> @@ -586,21 +585,19 @@ int winansi_isatty(int fd)
> *
> * https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx
> */
> - HANDLE handle = winansi_get_osfhandle(fd);
> - if (fd == STDIN_FILENO) {
> + {
> + HANDLE handle = (HANDLE)_get_osfhandle(fd);
> DWORD dummy;
>
> - if (!GetConsoleMode(handle, &dummy))
> - res = 0;
> - } else if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {
> - CONSOLE_SCREEN_BUFFER_INFO dummy;
> -
> - if (!GetConsoleScreenBufferInfo(handle, &dummy))
> - res = 0;
> + return !!GetConsoleMode(handle, &dummy);
> }
> + case 1:
> + return !!hconsole1;
> + case 2:
> + return !!hconsole2;
> }
>
> - return res;
> + return isatty(fd);
> }
>
> void winansi_init(void)
>