fix for [#20244] importing .obj without "Object" option checked crashes blender

release/scripts/modules/rna_prop_ui.py

@@ -143,7 +143,7 @@ rna_max = FloatProperty(name="Max", default=1.0, precision=3)
 class WM_OT_properties_edit(bpy.types.Operator):
     '''Internal use (edit a property path)'''
     bl_idname = "wm.properties_edit"
-    bl_label = "Edit Property!"
+    bl_label = "Edit Property"
 
     path = rna_path
     property = rna_property

source/blender/editors/mesh/mesh_data.c

@@ -676,7 +676,8 @@ void ED_mesh_material_add(Mesh *me, Material *ma)
 
 	me->mat = mat;
 	me->mat[me->totcol++] = ma;
-	ma->id.us++;
+	if(ma)
+		ma->id.us++;
 
 	test_object_materials((ID*)me);
 }