bpo-30225: Fix is_valid_fd() on macOS Tiger (#1443)
is_valid_fd() now uses fstat() instead of dup() on macOS to return 0
on a pipe when the other side of the pipe is closed. fstat() fails
with EBADF in that case, whereas dup() succeed.
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index afd4eb8..c0f41b3 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -1045,6 +1045,14 @@
static int
is_valid_fd(int fd)
{
+#ifdef __APPLE__
+ /* bpo-30225: On macOS Tiger, when stdout is redirected to a pipe
+ and the other side of the pipe is closed, dup(1) succeed, whereas
+ fstat(1, &st) fails with EBADF. Prefer fstat() over dup() to detect
+ such error. */
+ struct stat st;
+ return (fstat(fd, &st) == 0);
+#else
int fd2;
if (fd < 0)
return 0;
@@ -1057,6 +1065,7 @@
close(fd2);
_Py_END_SUPPRESS_IPH
return fd2 >= 0;
+#endif
}
/* returns Py_None if the fd is not valid */