Attached file run from IDLE edit window with 3.1, winxp works fine--
turtle moves in response to cursor keys-- if quit soon enough.
But after about 1000 key repeats, pythonw crashes with standard MSVC++
runtime error window, pythonw error window, and IDLE shell window
trackback ending with "RuntimeError: maximum recursion depth exceeded
while calling a Python object". The full traceback in appended to the file.

Disabling the undo buffer did not solve the problem.

Running the file from regular interpreter with
>>>exec(open(filename,'r').read())

gave essentially same result -- same traceback with slightly different
associated messages, so it is not an IDLE problem.

The demo/test at the bottem of turtle.py works fine -- but it does not
run as long.

I do not see the recursion, but calling the configuration merge with
every movement seems fishy.

resubmitting file

I can reproduce the crash on OSX.  After ~ 100 keystrokes, I get the following diagnostics:

Exception in Tkinter callback
Traceback (most recent call last):
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/tkinter/__init__.py", line 1399, in __call__
    return self.func(*args)
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/turtle.py", line 701, in eventfun
    fun()
  File "turtlecrash.py", line 12, in klt
    def klt(): seth(180); fd(vel)
  File "<string>", line 1, in seth
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/turtle.py", line 1936, in setheading
    self._rotate(angle)
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/turtle.py", line 3277, in _rotate
    self._update()
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/turtle.py", line 2660, in _update
    self._update_data()
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/turtle.py", line 2651, in _update_data
    self._pencolor, self._pensize)
  File "/Users/sasha/Work/python-svn/py3k-commit/Lib/turtle.py", line 545, in _drawline
    self.cv.coords(lineitem, *cl)
  File "<string>", line 1, in coords
RuntimeError: maximum recursion depth exceeded
Fatal Python error: Cannot recover from stack overflow.
Abort trap

This looks like a duplicate of issue11029.  It is not safe to call graphic primitives in event callbacks.  A workaround is described at <http://effbot.org/zone/tkinter-threads.htm>.

This is not a duplicate because this issue is about the stdlib turtle module doing something wrong and needing to be fixed. Also, this issue does not involve threads, at least none that I starting.

"It is not safe to call graphic primitives in event callbacks."

This is a confusing statement. The tutorial at
http://www.tkdocs.com/tutorial/canvas.html
by an experienced tk developer (19 years) includes this:

def addLine(event):
    global lastx, lasty
    canvas.create_line((lastx, lasty, event.x, event.y))
    lastx, lasty = event.x, event.y

Is canvas.create_line a primitive or not?

At the very least, unless I missed something, some change to turtle doc is needed.

"It is not safe to call graphic primitives in event callbacks."
Martin, do you agree that this is (or should be) the case?