Fix crash related to multiple inheritance

In the <class>_PTR_CppToPython_<class> converter function (written by
CppGenerator::writeConverterFunctions()), the generated code
used typeid(*ptr).name() to retrieve the name to use for the
SbkObjectTypes. This construct returns the name of the outermost
class (for example, "QWidget" for a QWidget-type paint device returned
by QPainter::device()), as opposed to "QPaintDevice *" returned by
typeid(ptr).name(). This caused a crash with multiple inheritance
since QWidget inherits QObject and QPaintDevice and the "QWidget"
type was associated with the QPaintDevice pointer.

To fix this:
- Add API to libshiboken to obtain the SbkObjectType* by name
  and check for the presence of a special cast function (multiple
  inheritance).
- Generate the code of <class>_PTR_CppToPython_<class> as follows:
  Check whether the outermost type obtained by typeid(*ptr).name()
  has a special cast function. If that is the case, use the
  type name obtained by typeid(ptr).name() (base class) to create
  the wrapper.

Change-Id: I8ee6b4c084e9dafa434623433661809b83aedee5
Fixes: PYSIDE-868
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/sources/shiboken2/libshiboken/basewrapper.h b/sources/shiboken2/libshiboken/basewrapper.h
index 65849d783..15682c600 100644
--- a/sources/shiboken2/libshiboken/basewrapper.h
+++ b/sources/shiboken2/libshiboken/basewrapper.h
@@ -238,6 +238,20 @@ LIBSHIBOKEN_API void        setSubTypeInitHook(SbkObjectType* self, SubTypeInitH
 LIBSHIBOKEN_API void*       getTypeUserData(SbkObjectType* self);
 LIBSHIBOKEN_API void        setTypeUserData(SbkObjectType* self, void* userData, DeleteUserDataFunc d_func);
 
+/**
+ * Return an instance of SbkObjectType for a C++ type name as determined by
+ * typeinfo().name().
+ * \param typeName Type name
+ * \since 5.12
+ */
+LIBSHIBOKEN_API SbkObjectType *typeForTypeName(const char *typeName);
+
+/**
+ *  Returns whether SbkObjectType has a special cast function (multiple inheritance)
+ * \param sbkType Sbk type
+ * \since 5.12
+ */
+LIBSHIBOKEN_API bool hasSpecialCastFunction(SbkObjectType *sbkType);
 }
 
 namespace Object {