screen drawing bug in Panic Prompt v1.3.2

gistfile1.py

#!/usr/bin/python
#
# reproduces a screen drawing bug in Panic Prompt v1.3.2
# reported by fjarlq on August 13, 2012
#
# good v1.3.1 behavior: counts on your screen from 0 to 9, updated each second
#
#  bad v1.3.2 behavior: it counts 0 and then 1 and then the counting stops
#

import os
import sys
import time

# moves the cursor to the screen coordinate (x, y)
def move_cursor(x, y):
        # writes ESC [ y ; x H
        sys.stdout.write("\33[" + str(y) + ";" + str(x) + "H")

# http://stackoverflow.com/questions/566746/how-to-get-console-window-width-in-python
def get_terminal_size():
        """
        returns (lines:int, cols:int)
        """
        import os, struct
        def ioctl_GWINSZ(fd):
                import fcntl, termios
                return struct.unpack("hh", fcntl.ioctl(fd, termios.TIOCGWINSZ, "1234"))
        # try stdin, stdout, stderr
        for fd in (0, 1, 2):
                try:
                        return ioctl_GWINSZ(fd)
                except:
                        pass
        # try os.ctermid()
        try:
                fd = os.open(os.ctermid(), os.O_RDONLY)
                try:
                        return ioctl_GWINSZ(fd)
                finally:
                        os.close(fd)
        except:
                pass
        # try `stty size`
        try:
                return tuple(int(x) for x in os.popen("stty size", "r").read().split())
        except:
                pass
        # try environment variables
        try:
                return tuple(int(os.getenv(var)) for var in ("LINES", "COLUMNS"))
        except:
                pass
        # i give up. return default.
        return (25, 80)

# bug repro:

(lines, cols) = get_terminal_size()

# reopen stdout with buffer length 0, disabling buffering
sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)

# clear screen
sys.stdout.write("\33[2J")

# write ints 0 through 9 at the next to last line on the screen.
# move the cursor to the beginning of the last line each time.
for i in range(10):
        move_cursor(1, lines - 1)
        sys.stdout.write(str(i))
        move_cursor(1, lines)
        time.sleep(1)