[Pythonmac-SIG] tcl/tk version confusion with tkinter in Python 2.6, on OS X

[Kevin Walzer]

njwilson23 at gmail.com wrote:
> I'm having trouble with tkinter on a new installation of Python (2.6),
> built with the framework option from source that was downloaded from
> python.org. I'm running OS 10.4 on a PowerPC G4.
> 
> The problem first arose when I tried to run matplotlib - it couldn't
> find tcl/tk because it was searching for 8.5, and I had 8.4. I found
> and built tcl/tk 8.5, which led to a new error, reproduced below:
> 
> Traceback (most recent call last):
>   File "brownian2.py", line 55, in <module>
>     main()
>   File "brownian2.py", line 41, in main
>     root = Tk()
>   File "/Library/Frameworks/Python.framework/Versions/2.6/lib/
> python2.6/lib-tk/Tkinter.py", line 1645, in __init__
>     self._loadtk()
>   File "/Library/Frameworks/Python.framework/Versions/2.6/lib/
> python2.6/lib-tk/Tkinter.py", line 1659, in _loadtk
>     % (_tkinter.TK_VERSION, tk_version)
> RuntimeError: tk.h version (8.4) doesn't match libtk.a version (8.5)
> 
> I'm a bit of a neophyte - can anyone tell me how to go about fixing
> this? I've found some information by searching the list and Google,
> but no helpful solutions.
> 
> Thanks,
> Nat

I haven't yet installed Python 2.6, but I've seen this error reported
here and on the MacPython list.

Based on what I'm seeing in the error message and in the setup.py file
in the source code, it appears that Python 2.6 is looking in
/System/Library/Frameworks for a Tcl/Tk installation rather than in
/Library/Frameworks, which is second on the list of places to look.
Tcl/Tk 8.4 comes standard with OS X in 10.4 and 10.5, and it's installed
in /System/Library/Frameworks. The problem is that Python 2.6 seems to
be linked against Tcl/Tk 8.5--is this correct?--and when it finds Tcl/tk
8.4, it returns an error.

You can avoid this problem by building Python yourself and putting
/Library/Frameworks first on the search path for Tcl/Tk. Look in
setup.py in the source code, around line  1438 (in the
'detect_tkinter_darwin' function), and either comment out
/System/Library or put it underneath /Library/Frameworks. This is what
the official build from Python.org should do--look first in
/Library/Frameworks and then fall back on /System/Library/Frameworks.
I'm not sure why it doesn't.

Should a bug report be filed against this? If the Mac build of Python
2.6 consistently looks in /System/Library/Frameworks for Tcl/Tk, it
won't run Tkinter applications. It makes the build pretty much useless
for anyone needing it to run Tkinter apps, including Idle. I'd say it's
a showstopper issue.

--Kevin

-- 
Kevin Walzer
Code by Kevin
http://www.codebykevin.com