Re: [PATCH] winansi_isatty(): fix when Git is used from CMD

> The code in winansi.c emulates ANSI escape sequences when Git is
> connected to the "real" windows console, CMD.exe. The details are
> outline in eac14f8909d9 (Win32: Thread-safe windows console output,
> 2012-01-14). Essentially, it plugs a pipe between C code and the actual
> console output handle.
> 
> This commit also added an override for isatty(), but it was made
> unnecessary by fcd428f4a952 (Win32: fix broken pipe detection,
> 2012-03-01).
> 
> The new isatty() override implemented by cbb3f3c9b197 (mingw: intercept
> isatty() to handle /dev/null as Git expects it, 2016-12-11) does not
> take into account that _get_osfhandle() returns the handle visible by
> the C code, which is the pipe. But it actually wants to investigate the
> properties of the handle that is actually connected to the outside
> world. Fortunately, there is already winansi_get_osfhandle(), which
> returns exactly this handle. Use it.
> 
> Signed-off-by: Johannes Sixt <j6t@kdbg.org>
> ---
> I was able to test the idea earlier than anticipated and it does work
> for me.

> diff --git a/compat/winansi.c b/compat/winansi.c
> index cb725fb02f..ba360be69b 100644
> --- a/compat/winansi.c
> +++ b/compat/winansi.c
> @@ -586,7 +586,7 @@ int winansi_isatty(int fd)
>  		 *
>  		 * https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx
>  		 */
> -		HANDLE handle = (HANDLE)_get_osfhandle(fd);
> +		HANDLE handle = winansi_get_osfhandle(fd);