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[Dick Hollenbeck <dick@xxxxxxxxxxx>]

> What do you think ?

https://bugs.launchpad.net/kicad/+bug/1299217/comments/12

I think you are my hero.

I've committed your fix in 4939, and marked the bug report as fixed.

Dick



On 06/12/2014 08:18 AM, Jean-Samuel Reynaud wrote:
> Hello,
> 
> I come back on this issue to give some pieces of analysis.
> 
> This issue is kicad bug #1299217 (https://bugs.launchpad.net/kicad/+bug/1299217)
> 
> Actual facts:
> When compile with option :
> KICAD_SCRIPTING_WXPYTHON=ON
> 
> 
> Pcbnew crash at startup with an error:
> 
> Traceback (most recent call last):
>   File "/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode/wx/__init__.py", line 45, in
> <module>
>     from wx._core import *
>   File "/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode/wx/_core.py", line 4, in <module>
>     import _core_
> ImportError: /usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode/wx/_core_.so: undefined
> symbol: PyExc_ValueError
> 
> 
> So I had try to investigate this point and I found that:
> 
> - libpython is correctly loaded at runtime (LD_DEBUG=all pcbnew)
>  => It is loaded because DSO _pcbnew.kiface depend to libpython
> 
> - pcbnew is not linked with libpython (of course, it doesn't use it directly...)
> - /usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode/wx/_core_.so is loaded by an
> embedded python scripts  at python_scripting.cpp
> 
> - this _core_.so is NOT linked with libpython
>  => I have check on my distribution: on 307 binary python module I have only 20 linked to
> libpython (including _pcbnew.so...)
>  => perhaps it is supposed to run inside a already load python system (like
> /usr/bin/python...) and it is not need to relink to python
> 
> - This old bug http://bugs.python.org/issue4434 look to be exactly the same case
> - libpython is not visible from other libs since at common/kiway.cpp the kiface dso is
> loaded *without* wxDL_GLOBAL
> 
> 
> 
> So a fix could be to add wxDL_GLOBAL to the dso.Load  (line 160 of common/kiway.cpp)
> 
> Additionnaly _pcbnew.so should not be linked to libpython since when loading it on python,
> python's symbols are already loaded. All other python binary libs don't link to libpython
> at all.
> 
> 
> What do you think ?
> 
> Le 04/04/2014 19:15, Dick Hollenbeck a écrit :
>>
>>>> I have try to find a solution by trace the library loading:
>>>> LD_DEBUG=all pcbnew
>>>> But the issue look to be due to a compilation option on some ubuntu
>>>> libs. Anyway I'm NOT sure of that...
>>
>> This is the right path to an understanding.  It's just that full source level debugging is
>> needed to see into libpython.so.  I don't think same for wxPython is needed, since the
>> crash is in libpython.so.
>>
>> It is a bit time consuming getting wxPython to be happy with a substitute libpython.so
>> (debug) and then capture the crash under a debugger, but this will begin to shed light.
>>
>> It may be related to thread local storage or something.  The differences in the crash
>> scenario and no crash are:
>>
>> 1) libpython is loaded as a load time dependency on the DSO in one case, vs. a load time
>> dependency on the EXE in the other
>>
>> 2) The DSO which depends on libpython, namely _pcbnew.kiface, is not loaded precisely at
>> at process startup time, but upon a dlopen() call later in time.
>>
>>
>>
>>
>>
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> 
> 
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