Turtle Graphics RawTurtle problem

[KentDLee]

BPO	22168
Nosy	@ned-deily
Files	c4.py issue22168.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/ned-deily'
closed_at = <Date 2014-09-14.07:05:33.357>
created_at = <Date 2014-08-08.01:27:43.349>
labels = ['expert-tkinter']
title = 'Turtle Graphics RawTurtle problem'
updated_at = <Date 2014-09-14.07:05:33.356>
user = 'https://bugs.python.org/KentDLee'

bugs.python.org fields:

activity = <Date 2014-09-14.07:05:33.356>
actor = 'ned.deily'
assignee = 'ned.deily'
closed = True
closed_date = <Date 2014-09-14.07:05:33.357>
closer = 'ned.deily'
components = ['Tkinter']
creation = <Date 2014-08-08.01:27:43.349>
creator = 'Kent.D..Lee'
dependencies = []
files = ['36307', '36447']
hgrepos = []
issue_num = 22168
keywords = ['patch']
message_count = 5.0
messages = ['225049', '225053', '225054', '225776', '226863']
nosy_count = 2.0
nosy_names = ['ned.deily', 'Kent.D..Lee']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue22168'
versions = ['Python 3.4', 'Python 3.5']

[KentDLee]

This is either a turtle graphics or tkinter problem.

In Python 3.4 it appears that something in Turtle Graphics broke or at least changed. I get the following error when trying to run a program that works in Python 3.1 and 3.2.

Kent's Mac> python3.4 c4.py
Traceback (most recent call last):
  File "c4.py", line 283, in <module>
    main()
  File "c4.py", line 277, in main
    animApp = Connect4Application(root)
  File "c4.py", line 110, in __init__
    self.buildWindow()
  File "c4.py", line 129, in buildWindow
    theTurtle = turtle.RawTurtle(canvas)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/turtle.py", line 2534, in __init__
    self.screen = TurtleScreen(canvas)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/turtle.py", line 1000, in __init__
    cv._rootwindow.call('wm', 'attributes', '.', '-topmost', '1')
AttributeError: 'Canvas' object has no attribute '_rootwindow'
Kent's Mac> 

The code is attached. The error occurs on line 129 when trying to create a RawTurtle and provide it with a Canvas.

[ned-deily]

It looks like the changes associated with bpo-11571, released in 3.4.1, cause this problem when the program supplies its own Canvas object rather than relying on the turtle module to create a default one.

[ned-deily]

As a temporary workaround, you could edit turtle.py to revert that change, in other words, just search for and delete the whole "if sys.platform == 'darwin'" test:

diff -r d85fcf23549e Lib/turtle.py
--- a/Lib/turtle.py     Tue Aug 05 14:02:11 2014 -0500
+++ b/Lib/turtle.py     Thu Aug 07 19:58:25 2014 -0700
@@ -993,12 +993,6 @@
         self._colormode = _CFG["colormode"]
         self._keys = []
         self.clear()
-        if sys.platform == 'darwin':
-            # Force Turtle window to the front on OS X. This is needed because
-            # the Turtle window will show behind the Terminal window when you
-            # start the demo from the command line.
-            cv._rootwindow.call('wm', 'attributes', '.', '-topmost', '1')
-            cv._rootwindow.call('wm', 'attributes', '.', '-topmost', '0')

     def clear(self):
         """Delete all drawings and all turtles from the TurtleScreen.

The file is at /Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/turtle.py.

[ned-deily]

The attached patch should prevent the AttributeError exception when not using a default Canvas. I now think the overall approach introduced in bpo-11571 is not the best. I plan to commit this fix for now but encourage more robust solutions in the long term.

[ned-deily]

The changesets below should prevent the problem in 3.4.2 and 3.5.0. Since there are no standard tests for turtle at the moment, there is no testcase for using a non-default Canvas but one should be added when turtle tests are (bpo-21914 and bpo-21916).

New changset fac17d06e01d by Ned Deily in branch '3.4':
Issue bpo-22168: Prevent turtle AttributeError with non-default Canvas on OS X.
https://hg.python.org/cpython/rev/fac17d06e01d

New changeset 775453a7b85d by Ned Deily in branch 'default':
Issue bpo-22168: Prevent turtle AttributeError with non-default Canvas on OS X.
https://hg.python.org/cpython/rev/775453a7b85d