Py_TPFLAGS_HEAPTYPE, what's its real meaning ?
Hi all, I've posted this question to the main python list, but got no answers, and I didn't see the issue arose on Python-dev (but I subscribed only two weeks ago). It concerns problems with the Py_TPFLAGS_HEAPTYPE and the new 'hackcheck' in python 2.3. I'm writing a C-extension module for python 2.3. I need to declare a new class, MyClass. For this class I want two things : 1) redefine the setattr function on objects of this class (ie setting a new tp_setattro) 2) I want that the python user can change attributes on MyClass (the class itself). Now I have a conflict on the Py_TPFLAGS_HEAPTYPE with new Python 2.3. If I have Py_TPFLAGS_HEAPTYPE set on MyClass, I'll have problem with the new hackcheck (Object/typeobject.c:3631), as I am a HEAPTYPE but I also redefine tp_setattro. If I don't have Py_TPFLAGS_HEAPTYPE, the user can't set new attributes on my class because of a check in type_setattro (Object/typeobject.c:2047). The only solution I've got without modifying python source is to create a specific Metaclass for Myclass, and write the tp_setattr. But I don't like the idea of making a copy-paste of the type_setattr source code, just to remove a check, this is not great for future compatibility with python (at each revision of Python I have to check if type_setattr has not change to copy-paste the changes). In fact I'm really wondering what's the real meaning of this flags, but I think there is some history behind it. If you think this is not the right place for this question, just ignore it, and sorry for disturbance. Boris
Boris Boutillier <Boris.Boutillier@arteris.net> writes:
No answers on this ? I posted the question two times on c.l.py and got no answers., help would be appreciated.
I answered, on comp.lang.python. I didn't say anything especially useful, though.
I think this is the appropriate solution: your type object is *not* a heap type (i.e. is not allocated on the heap) and you want to influence what happens when you set an attribute on it. Cheers, mwh -- I'd certainly be shocked to discover a consensus. ;-) -- Aahz, comp.lang.python
Boris Boutillier <Boris.Boutillier@arteris.net> writes:
No answers on this ? I posted the question two times on c.l.py and got no answers., help would be appreciated.
I answered, on comp.lang.python. I didn't say anything especially useful, though.
I think this is the appropriate solution: your type object is *not* a heap type (i.e. is not allocated on the heap) and you want to influence what happens when you set an attribute on it. Cheers, mwh -- I'd certainly be shocked to discover a consensus. ;-) -- Aahz, comp.lang.python
participants (2)
-
Boris Boutillier -
Michael Hudson