Building importable _tkinter on Windows

[Terry Reedy]

If you have tried to build _tkinter on Windows from the cpython 
repository, and have 'import tkinter' work, please share your 
experience, successful or not. I and another person have both failed.

Following the directions in the devguide (and for one step, 
PCBuild/readme), I did essentially the following.

* download and install TortoiseHG and an svn client (for external.bat)
* download and install c++ 2010 express
* in directory X, clone the python.org hg repository as cpython
* in X/cpython, run Tools/buildbot/external.bat to fetch and compile 
tcl/tk and other external dependencies.
* run visual studio with X/cpython/PCBuild/pcbuild.sln (I just double 
click on the .sln file. Choose c++ 2010 if other compilers are listed.

* build debug version of 3.4 (F7), stored as .../PCBuild/python_d.exe.
This also builds in the same directory things like _bz2_d.pyd and 
_lzma_d.pyd (whose dependencies are also fetched by external.bat) and 
_tkinter_d.pyd, apparently without error. The last is 43 kb. That is 
smaller than the others, but reasonable considering that it just 
forwards calls to tk. My installed 3.3 _tkinter.pyd is 41 kb.

* run python_d.exe. sys.path is
['',
'F:\\Python\\dev\\cpython\\PCbuild\\python34_d.zip',
'F:\\Python\\dev\\cpython\\DLLs',
'F:\\Python\\dev\\cpython\\lib',
'F:\\Python\\dev\\cpython\\PCbuild',  # where _tkinter, etc are
'F:\\Python\\dev\\cpython',
'F:\\Python\\dev\\cpython\\lib\\site-packages']

 >>> import bz2, lzma  # these import _bz2 and _lzma
 >>> import tkinter
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "F:\Python\dev\cpython\lib\tkinter\__init__.py", line 36, in 
<module>
     from tkinter import _fix
   File "F:\Python\dev\cpython\lib\tkinter\_fix.py", line 65, in <module>
     import _tkinter
ImportError: DLL load failed: The specified module could not be found.
[83479 refs, 32096 blocks]

My two hypotheses:

1. There is something wrong with _tkinter_d.pyd in particular such that 
it is not recognized as a dll file. To test this, I renamed my installed 
_tkinter, copied and renamed _tkinter_d, ran installed python 3.3, and 
got a similar error
ImportError: DLL load failed: %1 is not a valid Win32 application.
Perhaps this verifies the hypothesis, perhaps it is due to a mismatch 
between normal builds and debug builds.

2. CPython somehow special-cases the _tkinter import so that it fails in 
the fresh build environment. This seems dubious, but who knows?

Since the Windows buildbots build and test cpython more or less the same 
way, test/test_tkinter should pick up the same problem -- *if* it is 
actually run, but because of some problems with the test suite, I am not 
sure it is, rather than being skipped. Or maybe there is some 
significant small different in the buildbot process.

Does anyone have any idea what else I might do?

I expect to eventually post on pydev or the tracker, but I wanted to 
first try to collect more information here (which I wish more people 
would do).

-- 
Terry Jan Reedy