--- a/mercurial/util.py	Mon May 11 14:19:49 2009 +0200
+++ b/mercurial/util.py	Mon May 11 11:53:27 2009 -0700
@@ -1438,7 +1438,10 @@
         import termios, array, fcntl
         for dev in (sys.stdout, sys.stdin):
             try:
-                fd = dev.fileno()
+                try:
+                    fd = dev.fileno()
+                except AttributeError:
+                    continue
                 if not os.isatty(fd):
                     continue
                 arri = fcntl.ioctl(fd, termios.TIOCGWINSZ, '\0' * 8)