Mismatched c ptr types warning in closures when using cdef classes

[dmalcolm]

Am attempting to compile complex legacy code with cython (for speed) and am running into warnings in the generated .c code

Given the following:

import sys

cdef class Foo(object):
     def __init(self, log):
         self.log = log

     def bar(self):
         def inner(a):
             return self.log.write(str(a))

         self.log = sys.stdout
         inner(42)

cython-0.13 and latest cython-devel handles it, but I get compilation warnings from gcc on compiling the generated .c code:

$ cython innerfunction.pyx
$ gcc -I/usr/include/python2.6 -lpython2.6 innerfunction.c
innerfunction.c: In function ‘__pyx_pf_13innerfunction_3Foo_bar’:
innerfunction.c:547: warning: assignment from incompatible pointer type
innerfunction.c:575: warning: passing argument 1 of ‘PyObject_SetAttr’ from incompatible pointer type
/usr/include/python2.6/object.h:472: note: expected ‘struct PyObject *’ but argument is of type ‘struct __pyx_obj_13innerfunction_Foo *’

The error in question at line 547 is on this line:

  __pyx_cur_scope->__pyx_v_self = __pyx_v_self;

where:

struct __pyx_obj_13innerfunction___pyx_scope_struct_bar {
  PyObject_HEAD
  PyObject *__pyx_v_inner;
  struct __pyx_obj_13innerfunction_Foo *__pyx_v_self;
};

and the locals are:

  PyObject *__pyx_v_self
  struct __pyx_obj_13innerfunction___pyx_scope_struct_bar *__pyx_cur_scope;

so the closure struct has a ptr to the underlying struct class, whereas self is a PyObject?*

Similarly, at line 575, we have:

  if (PyObject_SetAttr(__pyx_cur_scope->__pyx_v_self, __pyx_n_s__log, __pyx_t_2) < 0)

where the compiler is unhappy with the passing of the subclass*, rather than a PyObject?*

Obviously these are safely cast-able in both cases, but it would be nicer to avoid compilation warnings.