[matplotlib-devel] crash on matplotlib.matlab import on win32 - solution and question...

[Gregory L. <gre...@ff...>]

I continued investigating the crash occuring on my laptop, and found a
"solution" :-)
The problem occur precisely in font_manager.py, in the function
createFontDict. 
In this function, there is a loop over a fontfiles list, that for me is
made of 353 files.
This loop works ok for 221 fontfiles, then crash...
Now maybe this is a lot of font files compared to typical windows
install, hence the crash on my system? At least I am sure this is a
difference between the other WinXP and Win2000 laptop I tested,
explaining why only mine did crash...I am now confident this is the
origin of my Laptop problem, not some strange Voodoo malediction ;-) Why
this occur with numarray and not numeric is maybe voodoo-related, though
;-)).
During this Loop, special default font files are found, and renamed
serif, sans-serif, cursive...in fact multiple occurrence of each default
font is found (3 monospace for example)...Again, I do not understand
fully the routine yet but maybe this is a problem, (especially as a
comment before the default font attribution mention thet this algorithm
need improvement ;-) ) I guess adding multiple fonts in the fontdict
under the same name, will induce a destruction of the previous font
stored with this key/name...now if prop contains a numerix array, this
can explain the different behavior of numarray/numeric :-)
Now if I stop the loop before this deadly 221th font, from
matplotlib.matlab import * complete and I am able to plot in a TkAgg
window my sin(x) :-)
After that, this dictionary seems pickled in a cache and this routine is
never run again, explaining maybe why this behavior  was never noted:
maybe it does not occur often, and once the loop has completed you are
safe.

I am ready to do more testing if you need more info about this, but I
feel from now on maybe somebody with better knowledge of the matplotlib
internals will be faster than me to locate the problem...So if I can
still do something, please tell me...

BTW, the matplotlib I tested is 0.60b but I had the same crash with the
previous non-beta version , so I guess the problem is the same...

Best regards,

Greg.