Fix glitch in voidptr.cpp after the PEP 384 commit

By lots of editing, somehow an expression in voidptr.cpp
became incomplete.
We should improve the current test to be certain that the
VoidPtr is working.

This problem can be avoided by not doing many type
casts at once.
Doing the same in two steps is much safer because a forgotten
call would give a compile time error.

Task-number: PYSIDE-560
Change-Id: Ibb24a27f439cbda490723131f34f93978725420f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 7 insertions, 2 deletions

diff --git a/sources/shiboken2/libshiboken/voidptr.cpp b/sources/shiboken2/libshiboken/voidptr.cpp
index afb3f4040..94c667598 100644
--- a/sources/shiboken2/libshiboken/voidptr.cpp
+++ b/sources/shiboken2/libshiboken/voidptr.cpp
@@ -55,8 +55,13 @@ typedef struct {
 
 PyObject *SbkVoidPtrObject_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 {
-    SbkVoidPtrObject *self =
-        reinterpret_cast<SbkVoidPtrObject *>(PepType(type)->tp_alloc);
+    // PYSIDE-560: It is much safer to first call a function and then do a
+    // type cast than to do everything in one line. The bad construct looked
+    // like this, actual call forgotten:
+    //    SbkVoidPtrObject *self =
+    //        reinterpret_cast<SbkVoidPtrObject *>(PepType(type)->tp_alloc);
+    PyObject *ob = PepType(type)->tp_alloc(type, 0);
+    SbkVoidPtrObject *self = reinterpret_cast<SbkVoidPtrObject *>(ob);
 
     if (self != 0) {
         self->cptr = 0;