Exppython: fixed crash caused by linking to a scene objects with NULL obdata,...

Exppython: fixed crash caused by linking to a scene objects with NULL obdata, caused by recent (2.28c) internal changes to avoid unneded creation of obdata.

source/blender/python/api2_2x/Object.c

@@ -531,15 +531,11 @@ static PyObject *Object_clrParent (BPy_Object *self, PyObject *args)
 		return (Py_None);
 }
 
-static PyObject *Object_getData (BPy_Object *self)
+/* adds object data to a Blender object, if object->data = NULL */
+int EXPP_add_obdata(struct Object *object)
 {
-    PyObject  * data_object;
-    Object * object = self->object;
+	if (object->data != NULL) return -1;
 
-    /* If there's no data associated to the Object, then there's nothing to */
-    /* return. */
-    if (object->data == NULL)
-    {
 	switch(object->type)
 	{
 		case OB_ARMATURE:
@@ -587,6 +583,24 @@ static PyObject *Object_getData (BPy_Object *self)
 			break;
 		*/
 		default:
+			break;
+	}
+
+	if (!object->data) return -1;
+
+	return 0;
+}
+
+static PyObject *Object_getData (BPy_Object *self)
+{
+		PyObject	* data_object;
+		Object * object = self->object;
+
+		/* if there's no obdata, try to create it */
+		if (object->data == NULL)
+		{
+			if (EXPP_add_obdata(object) != 0)
+			{ /* couldn't create obdata */
 				Py_INCREF (Py_None);
 				return (Py_None);
 			}

source/blender/python/api2_2x/Object.h

@@ -73,4 +73,6 @@ typedef struct {
     struct Object   * object;
 } BPy_Object;
 
+int EXPP_add_obdata(struct Object *object);
+
 #endif /* EXPP_OBJECT_H */

source/blender/python/api2_2x/Scene.c

@@ -594,6 +594,10 @@ static PyObject *Scene_link (BPy_Scene *self, PyObject *args)
 			return EXPP_ReturnPyObjError (PyExc_MemoryError,
 							"couldn't allocate new Base for object");
 
+		/* check if this object has obdata, case not, try to create it */
+		if (!object->data && (object->type != OB_EMPTY))
+			EXPP_add_obdata(object); /* returns -1 on error, defined in Object.c */
+
 		base->object = object; /* link object to the new base */
 		base->lay = object->lay;
 		base->flag = object->flag;

source/blender/python/api2_2x/doc/Scene.py

@@ -15,13 +15,25 @@ Example::
   camdata = Camera.New('ortho')           # create new camera data
   camdata.setName('newCam')
   camdata.setLens(16.0)
-  camobj = Object.New('Camera')           # create a new camera object
-  camobj.link(camdata)                    # link data to object
   scene = Scene.New('NewScene')           # create a new scene
-  scene.link(camobj)                      # link object to scene
+  camobj = Object.New('Camera')           # create a new camera object
+  camobj.link(camdata)                    # (*) link data to object first
+  scene.link(camobj)                      # and then link object to scene
   scene.frameSettings(1, 100 ,1)          # set start, end and current frames
   scene.setWinSize(640, 480)              # set the render window dimensions
   scene.makeCurrent()                     # make this the current scene
+
+@warn: as done in the example (*), it's recommended to first link object data to
+    objects and only after that link objects to scene.  This is because if
+    there is no object data linked to an object ob, scene.link(ob) will
+    automatically create the missing data.  This is ok on its own, but I{if
+    after that} this object is linked to obdata, the automatically created one
+    will be discarded -- as expected -- but will stay in Blender's memory
+    space until the program is exited, since Blender doesn't really get rid of
+    most kinds of data.  So first linking obdata to object, then object to
+    scene is a tiny tiny bit faster than the other way around and also saves
+    some realtime memory (if many objects are created from scripts, the
+    savings become important).
 """
 
 def New (name = 'Scene'):