[Urwid] Problem with Text widgets & leading spaces

[Rebecca Breu]

Hi all!

I observed a problem with Text widgets that begin with a space.

If I put such Text widgets into a ListBox, and resize the terminal window
to something very narrow, that can lead to an AssertionError. Without leading
spaces (if I replace them by underscores, for example), all works just fine.

Here is my program:

###################################################################
#! /usr/bin/env python

import urwid.curses_display;
import urwid;

def body():

    mylist = urwid.ListBox([urwid.Text(" Die Gedanken sind frei,"),
                            urwid.Text(" wer kann sie erraten?")]);
    return mylist;


def run():

    dim = ui.get_cols_rows();
    main_view = body();

    #Main event loop:
    while True:
        ui.draw_screen(dim, main_view.render(dim, True));
	keys = ui.get_input()

	if "window resize" in keys:
            dim = ui.get_cols_rows();
            main_view = body();


ui = urwid.curses_display.Screen();
ui.run_wrapper(run)

######################################################################

You may have to try out which terminal size lets the program crash.
For me, it's an aterm or xterm with *exactly* width 3.

The backtracke is the following:

######################################################################

Traceback (most recent call last):
  File "./test.py", line 35, in ?
    ui.run_wrapper(run)
  File "/home/rbreu/unicore/config_server/config_bin/urwid/curses_display.py",
line 160, in run_wrapper
    return fn()
  File "./test.py", line 23, in run
    ui.draw_screen(dim, main_view.render(dim, True));
  File "/home/rbreu/unicore/config_server/config_bin/urwid/listbox.py", line
254, in render
    focus_canvas = focus_widget.render((maxcol,), focus=focus)
  File "/home/rbreu/unicore/config_server/config_bin/urwid/widget.py", line 166,
in render
    maxcol )
  File "/home/rbreu/unicore/config_server/config_bin/urwid/canvas.py", line 362,
in apply_text_layout
    s = LayoutSegment(seg)
  File "/home/rbreu/unicore/config_server/config_bin/urwid/util.py", line 300,
in __init__
    assert self.sc > 0, `seg`
AssertionError: (0, 0, 0)

######################################################################

I'm using:

urwid-0.9.1
python 2.4.1
Linux-2.6.13 (SuSE-10.0-i586)


Greetings,
Rebecca