Nils Bruin, 22.11.2013 00:10: > With the following classes: > > cdef class A(object): > cdef int a > pass > cdef class B(object): > pass > > and the following multiply inherited classes: > > The problem arises > > class C(object): > pass > class D(C,B): > pass > class F(B,C): > pass > class E(C,A): > pass > class G(A,C): > pass > > I observe: > > >>> D.__new__(D) > > B.__new__(D) is not safe, use object.__new__() > > >>> E.__new__(E) > > <__main__.E object at 0x6c56488> > > >>> F.__new__(F) > > <__main__.F object at 0x6c4fdd0> > >>> G.__new__(G) > <__main__.G object at 0x6c4fdd0> > > > As you can see, a problem only arises for D, in which case there is > actually NOT a layout problem: when the class A is involved, where it does > matter which __new__ is used, that right one (I assume) is chosen in all > cases. A little googling suggests that this error might be coming from > tp_new_wrapper in Objects/typeobject.c, which tries to do some sanity > checks before calling type->tp_new. It is not clear to me, however, why > those sanity checks fail for D.__new__(D) and succeed for E.__new__(E)
I came up with this fix: https://github.com/cython/cython/commit/ec37469dc61e0e24db448e9455b2483797afe936 It passes your test case and doesn't seem to break others so far. However, this is a bit of a deep change, so I'd like to see some serious user side testing before I'll happily push for its inclusion in Cython 0.20. Stefan _______________________________________________ cython-devel mailing list cython-devel@python.org https://mail.python.org/mailman/listinfo/cython-devel
