Re: [matplotlib-devel] RE : [Matplotlib-users] crash on matplotlib.matlab import on win32

[John H. <jdh...@ac...>]

>>>>> "Gregory" == Gregory Lielens <gre...@ff...> writes:

    Gregory> I checked on another WinXP computer, and it works on this
    Gregory> one - seems that I have to play the windows re-install
    Gregory> game, or hunt down what the exact differences between
    Gregory> these 2 WinXP computers are :-/...  The fact that only
    Gregory> matplotlib exhibit this behavior is strange though, I
    Gregory> checked in the code (hence cc to the devel list) and the
    Gregory> problem is linked to an assert in the destructor of
    Gregory> PythonExtensionBase, checking that the ref counting of
    Gregory> this object is 0 and exiting Python interpreter if it is
    Gregory> not the case...Hum, obviously I do not know the code at
    Gregory> all, but could the problem be linked to a destruction
    Gregory> sequence beeing somewhat different on my computer (for
    Gregory> whatever reasons :-/)?  This worry me (in addition to
    Gregory> bother me not beeing able to run matplotlib on my laptop
    Gregory> for the moment ;-) ), cause it may be the sign of
    Gregory> "difficult to solve and reproduce" installation problems
    Gregory> for a package we may use in a distributed software
    Gregory> package in the future...  I will keep investigating, but
    Gregory> if there is a developer have any idea about this (like, a
    Gregory> hint about why there is this assert there and what can
    Gregory> cause it to fail), it would be great!

CXX is the python wrapper generator code used to write most of the C++
python extensions that matplotlib uses.  Among other things, it helps
automate reference counting for python objects, but in many cases
needs some assistance from the operator (me).  Since I've been
actively working on the reference counts in a number of parts of the
code to fix some memory leaks, there is a good chance that I screwed
up somewhere.

There are two things that would be useful to know:

  * Is this specific to python 2.3.4?  Is this the same version of
    python on all the machines you tested, or is there a difference
    between the python versions on the machines that crashed and the
    machine that worked?  I also tested on Windows XP with no
    problems, using the enthought edition of python.

  * If instead of importing TkAgg, you simply import Agg, on a machine
    that crashes, do you still get the crash?  It would be nice to
    narrow the focus.

I have done a fair amount of work since 0.54.2 fixing more memory
leaks - there is always a possibility that the problem has already
been fixed.  If you can provide the information above, I can send you
a debug build of the current development snapshot that might provide
more information.  Basically, it prints each function call to
stdout which sometimes help debug a segfault and other errors.

Thanks for your help,
JDH