Search Issue Tracker

By Design

By Design in 2017.1.X



Found in


Issue ID




Undo.RecordObject fails to properly record new list elements if the object is a prefab instance

Scene Management


How to reproduce:
1. Download attached project file
2. Create a new GameObject and add an "AnimationPlayer" script to it.
3. Turn this new GameObject into a prefab by dragging it into the assets view.
4. Select Prefab in Hierarchy window and press the "Add 2D Blend Tree" button in Inspector (Important! Don't apply changes after adding the 2D blend tree.)
5. Enter Play Mode

Actual result: When a MonoBehaviour is an instance of a Prefab, Undo.RecordObject fails to properly record some details when adding objects to a list, causing data to be lost when entering Play Mode or leaving the scene. The same changes will be applied properly if the MonoBehaviour is not a part of a prefab.

In technical detail; if the MonoBehaviour is a Prefab, an addition to a List<Foo> where Foo is a serializable class causes the prefab override to store the new List size, but no information about the new element.

Reproduced with: 2017.1.2f1, 2017.2.0f3, 2017.3.0b3

Comments (1)

  1. MorCompediaNet

    Dec 12, 2017 18:31

    Just adding in that this is true not only for lists of custom types, but also lists of strings and primitives.
    Also, arrays don't work either, it seems to be a problem with generic collections.

Add comment

Log in to post comment

All about bugs

View bugs we have successfully reproduced, and vote for the bugs you want to see fixed most urgently.