On 30 March 2014 03:05, Ethan Furman <et...@stoneleaf.us> wrote: > > This bit of code won't even finish compiling. I am not sure if my > understanding of references (and how these functions create/consume them) or > my understanding of when and where to call PyErr_Fetch|Restore or > PyException_SetContext is at fault, but I would greatly appreciate somebody > correcting my understanding. :)
I had to figure this out for the codec exception chaining in Python 3.4, and the main piece that appears to be missing from your code is an appropriate call to PyErr_NormalizeException(). (The interpreter tries to avoid actually instantiating exceptions if it can, with the consequence that explicit normalisation is often needed before non-trivial operations on the current exception) This is the code that does the heavy lifting for the codec exception chaining in Python 3.4: http://hg.python.org/cpython/file/36492f927a40/Objects/exceptions.c#l2644 Sine you're raising a genuinely new exception, rather than implicitly replacing an existing one, you don't need all the checks I have in that function to make sure the implicit replacement is OK. You'd just need some more like the final section that actually creates the new exception and links it up with the old one: http://hg.python.org/cpython/file/36492f927a40/Objects/exceptions.c#l2764 Setting the context correctly for exceptions raised in C should be similar to that, just setting the context rather than the cause. (Although don't forget the bit earlier in the function that populates the traceback correctly on the original exception) I thought I had filed a "Add a public API to make properly chained exceptions easier to raise from C" RFE while working on the codec chaining, but I'm not seeing anything now... Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
