For a while now, I've noticed test_tcl locking up when trying to refleaktest it. I was able to reproduce it quite simply:

import Tkinter
import os

if "DISPLAY" in os.environ:
    del os.environ ["DISPLAY"]

tcl = Tkinter.Tcl()
try:
    tcl.loadtk()
except Exception, e:
    print e
tcl.loadtk()

Or, more directly, using _tkinter directly:

import _tkinter
import os

if "DISPLAY" in os.environ:
    del os.environ["DISPLAY"]

tk = _tkinter.create(None, "test", "Tk", 0, 1, 0)
try:
    tk.loadtk()
except:
    pass
tk.loadtk()

In either case, the second loadtk never finishes.

It seems that, on my platform at least, Tk_Init() doesn't like being called twice even when the first call resulted in an error. That's Tcl and Tk 8.4.12. Tkapp_Init() (which is the Tkinter part that calls Tk_Init()) does its best to guard against calling Tk_Init() twice when the first call was succesful, but it doesn't remember failure cases. I don't know enough about Tcl/Tk or Tkinter how this is best handled, but it would be mightily convenient if it were. ;-) I've created a bugreport on it, and I hope someone with Tkinter knowledge can step in and fix it. (It looks like SF auto-assigned it to Martin already, hmm.)

http://sourceforge.net/tracker/index.php?func=detail&aid=1475162&group_id=5470&atid=105470

--
Thomas Wouters <thomas@python.org>

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