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Patch #1623563: allow __class__ assignment for classes with __slots__.

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The old and the new class are still required to have the same slot
names, but the order in which they are specified is not relevant.
This commit is contained in:
Žiga Seilnacht 2007-03-16 11:59:38 +00:00
parent 6ab8452036
commit 6f2d09c949
5 changed files with 84 additions and 4 deletions
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31
Objects/typeobject.c
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@ -1844,8 +1844,11 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
}
}
/* Copy slots into yet another tuple, demangling names */
newslots = PyTuple_New(nslots - add_dict - add_weak);
/* Copy slots into a list, mangle names and sort them.
Sorted names are needed for __class__ assignment.
Convert them back to tuple at the end.
*/
newslots = PyList_New(nslots - add_dict - add_weak);
if (newslots == NULL)
goto bad_slots;
for (i = j = 0; i < nslots; i++) {
@ -1858,13 +1861,23 @@ type_new(PyTypeObject *metatype, PyObject *args, PyObject *kwds)
tmp =_Py_Mangle(name, tmp);
if (!tmp)
goto bad_slots;
PyTuple_SET_ITEM(newslots, j, tmp);
PyList_SET_ITEM(newslots, j, tmp);
j++;
}
assert(j == nslots - add_dict - add_weak);
nslots = j;
Py_DECREF(slots);
slots = newslots;
if (PyList_Sort(newslots) == -1) {
Py_DECREF(bases);
Py_DECREF(newslots);
return NULL;
}
slots = PyList_AsTuple(newslots);
Py_DECREF(newslots);
if (slots == NULL) {
Py_DECREF(bases);
return NULL;
}
/* Secondary bases may provide weakrefs or dict */
if (nbases > 1 &&
@ -2481,6 +2494,7 @@ same_slots_added(PyTypeObject *a, PyTypeObject *b)
{
PyTypeObject *base = a->tp_base;
Py_ssize_t size;
PyObject *slots_a, *slots_b;
if (base != b->tp_base)
return 0;
@ -2491,6 +2505,15 @@ same_slots_added(PyTypeObject *a, PyTypeObject *b)
size += sizeof(PyObject *);
if (a->tp_weaklistoffset == size && b->tp_weaklistoffset == size)
size += sizeof(PyObject *);
/* Check slots compliance */
slots_a = ((PyHeapTypeObject *)a)->ht_slots;
slots_b = ((PyHeapTypeObject *)b)->ht_slots;
if (slots_a && slots_b) {
if (PyObject_Compare(slots_a, slots_b) != 0)
return 0;
size += sizeof(PyObject *) * PyTuple_GET_SIZE(slots_a);
}
return size == a->tp_basicsize && size == b->tp_basicsize;
}