Why are m_SizeDelta and m_AnchoredPosition values changing in scene file for no reason, complicating merge?

Questions & Answers
1

I’m using UnityYAMLMerge with a version control system, and it works great, but it has exposed the fact that many m_SizeDelta and m_AnchoredPosition values in my scene are changing spontaneously, without my making the changes.

For example, I edit one object’s x position and then save the scene. My coworker starts from the same version of the scene file I started with, and also edits one object’s position. When we then attempt to merge our changes, UnityYAMLMerge shows us that besides the changes we made, there are many (usually eg. 45-200) objects in the scene file whose m_SizeDelta and/or m_AnchoredPosition values have changed (to different, conflicting values). For the most part the values have changed by a small amount, less than 1.0, but some show larger changes.

These spontaneous changes produce dozens of conflicts that we then need to resolve manually, making the process of merging a simple change in a scene file very time consuming.

Any idea why these m_SizeDelta and m_AnchoredPosition values are changing, and how to prevent it?

3

What I’ve gathered from looking through my scene file is that the gameobjects having their m_SizeDelta and m_AnchoredPosition changed automatically are those that are having their position and/or size set automatically due to being children of an object that has a Vertical (or Horizontal) Layout Group component, and a Content Size Fitter component.

Still don’t know why it’s changing these values between saves of the scene file (when I am not altering those objects at all between saves), or how to prevent it from doing so.

4

The following article describes a possible fix:

2

I’m having the same issue. One of our team saves a scene file, I reload it and instantly it’s being marked that’s something changed. I save the scene, look at the changes in a diff program (P4Merge), and a whole host of m_SizeDelta + m_AnchoredPosition have changed.

It’s very annoying, as like you say, it makes merging much more difficult (and people are saving + checking in the scene more often than needed)