Description of problem:

preupg
This kind of execution:

# yes | preupg --debug

causes following traceback:

Traceback (most recent call last):
  File "/usr/bin/preupg", line 33, in <module>
    sys.exit(main())
  File "/usr/bin/preupg", line 20, in main
    ret = app.run()
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 680, in run
    tarball_path = self.scan_system()
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 516, in scan_system
    self.run_scan_process()
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 290, in run_scan_process
    self.run_scan(function=self.scanning_progress.show_progress)
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 307, in run_scan
    return run_subprocess(cmd, print_output=False, function=function)
  File "/usr/lib/python2.6/site-packages/preup/utils.py", line 140, in run_subprocess
    function(stdout_data.decode(settings.defenc))
  File "/usr/lib/python2.6/site-packages/preup/scanning.py", line 86, in show_progress
    self.width_size = int(ScanProgress.get_terminal_width()[1])
IndexError: list index out of range

I can just guess get ScanProgress.get_terminal_width reads attributes of stdin, however in this case stdin isn't tty.

Version-Release number of selected component (if applicable):
preupgrade-assistant-2.1.0-7.el6.x86_64

How reproducible:
write to stdin of preupg via pipe

Steps to Reproduce:
1. yes | preupg

Actual results:
Traceback raised.

Expected results:
No traceback