@matheusbsbs / matheus-bagliano / commits / cbb3f3c9b1

mingw: intercept isatty() to handle /dev/null as Git expects it

When Git's source code calls isatty(), it really asks whether the respective file descriptor is connected to an interactive terminal. Windows' _isatty() function, however, determines whether the file descriptor is associated with a character device. And NUL, Windows' equivalent of /dev/null, is a character device. Which means that for years, Git mistakenly detected an associated interactive terminal when being run through the test suite, which almost always redirects stdin, stdout and stderr to /dev/null. This bug only became obvious, and painfully so, when the new bisect--helper entered the `pu` branch and made the automatic build & test time out because t6030 was waiting for an answer. For details, see https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Johannes Schindelin committed Dec 11, 2016 at 12:16 UTC cbb3f3c9b1975c9bdd07f24fc4ef4e504507adaa

2 files changed +36

compat/mingw.h

@@ -384,6 +384,9 @@ int mingw_raise(int sig);

384 * ANSI emulation wrappers

385 */

386

387 +int winansi_isatty(int fd);

388 +#define isatty winansi_isatty

389 +

390 void winansi_init(void);

391 HANDLE winansi_get_osfhandle(int fd);

392

compat/winansi.c

+33

@@ -7,6 +7,9 @@

7 #include <wingdi.h>

8 #include <winreg.h>

10 +/* In this file, we actually want to use Windows' own isatty(). */

11 +#undef isatty

12 +

13 /*

14 ANSI codes used by git: m, K

@@ -570,6 +573,36 @@ static void detect_msys_tty(int fd)

573

574 #endif

575

576 +int winansi_isatty(int fd)

577 +{

578 + int res = isatty(fd);

579 +

580 + if (res) {

581 + /*

582 + * Make sure that /dev/null is not fooling Git into believing

583 + * that we are connected to a terminal, as "_isatty() returns a

584 + * nonzero value if the descriptor is associated with a

585 + * character device."; for more information, see

586 + *

587 + * https://msdn.microsoft.com/en-us/library/f4s0ddew.aspx

588 + */

589 + HANDLE handle = (HANDLE)_get_osfhandle(fd);

590 + if (fd == STDIN_FILENO) {

591 + DWORD dummy;

592 +

593 + if (!GetConsoleMode(handle, &dummy))

594 + res = 0;

595 + } else if (fd == STDOUT_FILENO || fd == STDERR_FILENO) {

596 + CONSOLE_SCREEN_BUFFER_INFO dummy;

597 +

598 + if (!GetConsoleScreenBufferInfo(handle, &dummy))

599 + res = 0;

600 + }

601 + }

602 +

603 + return res;

604 +}

605 +

606 void winansi_init(void)

607 {

608 int con1, con2;