[Pyrex] Exception stomping

[Stefan Behnel]

Stefan Behnel wrote:
> Eric Huss wrote:
>> I've run into a problem with how Pyrex handles the "current" exception
>> (not sure if this has been discussed before).  I know that the "reraise"
>> issue has been fixed, but this is a slightly different issue where Pyrex
>> does not make a backup of the "current" exception.
>>
>> If you call a Pyrex function that internally raises and catches an
>> exception, but does not re-raise it, it leaves that exception set within
>> the tstate object.  This causes the exception to bleed out in unexpected
>> ways.
> 
> Please take a look at the way Cython 0.10.1 handles this. It stores the
> current exception away when it enters a try block and restores it when an
> exception has been caught in an except block and successfully handled (i.e.
> the except block has exited normally).

Here are the relevant test cases:

http://hg.cython.org/cython-devel/file/tip/tests/run/funcexcept.pyx
http://hg.cython.org/cython-devel/file/tip/tests/run/funcexceptchained.pyx
http://hg.cython.org/cython-devel/file/tip/tests/run/funcexceptcypy.pyx
http://hg.cython.org/cython-devel/file/tip/tests/run/funcexceptreturn.pyx
http://hg.cython.org/cython-devel/file/tip/tests/run/exceptionrefcount.pyx

Stefan