fix for a crash in Blender.Mesh,

getting curve data from an object failed (with only 1 curve vertex)
Blender.Mesh didnt check this and crashed.

source/blender/blenkernel/intern/mesh.c

@@ -808,6 +808,7 @@ void mball_to_mesh(ListBase *lb, Mesh *me)
 	}	
 }
 
+/* this may fail replacing ob->data, be sure to check ob->type */
 void nurbs_to_mesh(Object *ob)
 {
 	Object *ob1;
@@ -847,7 +848,8 @@ void nurbs_to_mesh(Object *ob)
 		dl= dl->next;
 	}
 	if(totvert==0) {
-		error("can't convert");
+		/* error("can't convert"); */
+		/* Make Sure you check ob->data is a curve */
 		return;
 	}
 

source/blender/python/api2_2x/Mesh.c

@@ -5704,6 +5704,10 @@ static PyObject *Mesh_getFromObject( BPy_Mesh * self, PyObject * args )
 		nurbs_to_mesh( tmpobj );
 		tmpmesh = tmpobj->data;
 		free_libblock_us( &G.main->object, tmpobj );
+		
+		if (ob->type != OB_MESH)
+			return EXPP_ReturnPyObjError( PyExc_RuntimeError,
+				"cant convert curve to mesh. Does the curve have any segments?" );
  		break;
  	case OB_MBALL:
 		/* metaballs don't have modifiers, so just convert to mesh */

source/blender/src/editobject.c

@@ -2527,9 +2527,12 @@ static void curvetomesh(Object *ob)
 	if(dl==0) makeDispListCurveTypes(ob, 0);		/* force creation */
 
 	nurbs_to_mesh(ob); /* also does users */
-	
+	if (ob->type != OB_MESH) {
+		error("can't convert curve to mesh");
+	} else {
 		object_free_modifiers(ob);
 	}
+}
 
 void convertmenu(void)
 {