[PyQt] Exception handling crash

Arve Knudsen arve.knudsen at gmail.com
Fri Jun 13 10:54:47 BST 2008


I'm still having problems with SIP's exception handling support, using
SIP snapshot 20080612). When an exception from my wrapped C++ code is
caught, SIP triggers an error in the Python API (PyEval_SaveThread:
NULL tstate), The relevant backtrace looks as follows:

#3  0xb6854968 in Py_FatalError () from /usr/lib/libpython2.5.so.1.0
#4  0xb682cad5 in PyEval_SaveThread () from /usr/lib/libpython2.5.so.1.0
#5  0xb2627b69 in release_QString (sipCppV=0x825e3c0) at
#6  0xb279c2db in release (addr=0x825e3c0, td=0xb27813a0, state=1) at
#7  0xb279c299 in sip_api_release_instance (cpp=0x825e3c0,
type=0x8495354, state=1) at siplib.c:5633
#8  0xb2503186 in meth_BuildProject2_loadProject (sipArgs=0x854f9cc)
at sip_wrapperBuildProject2.cpp:669

AFAICT the problem is that outside the try block there is a call to
Py_BEGIN_ALLOW_THREADS, which releases the GIL? Then, first thing
after the exception is caught, an QString is released (a parameter to
the wrapped method). As part of releasing the QString, in
release_QString, Py_BEGIN_ALLOW_THREADS is called again, which is not
allowed since the GIL is not being held, right?

>From what I understand there is a simpler alternative to
PyGILState_Ensure/PyGILState_Release. Could SIP make use of these
functions instead?


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