Setting the m_Name field for MonoBehaviours in YAML files

Unity Engine
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1

Hello,

Is there a way to set the m_Name field in MonoBehaviour blocks in YAML files? It would be easier to parse diffs if MmonoBehaviours had human-readable names. Maybe it’s something extra we could be setting programmatically?

GameObject has its m_Name set via the GameObject.name property but I can’t find any way to set it for MonoBehaviours.

Thanks,
Vladimir

2

Components do not have their own name. All components share the name with the gameobject they are attached to as you can read in the documentation.

3

It does in the YAML though, it’s just that the field is empty.

It would be easier to figure out which component was added to a GameObject just by looking at the diff (while reviewing a PR, for example) if the component had the m_Name filled out.
Right now we have to look at serialized fields and divine which component was edited (if it has exposed fields at all).

4

It’s empty because Component.name just points to GameObject.name. The field is otherwise unused by components, even if it has an empty serialised field for it.

I imagine it is probably possible by making a SerializedObject out of a component, and getting the SerializedProperty for m_Name and writing to that.

5

Hey @spiney199 , I just tested that approach and it works. Now if I could expand this to affect ALL components, not just ones I’ve written and hook up elegantly (ie. not require a per-class call from something like OnValidate to a function that sets m_Name or doing a MonoBehaviour subclass).

Maybe some MonoBehaviour or Editor event I could hook into?

6

I guess this is a use case for ObjectChangeEvents: Example of how to use ObjectChangeEvents in Unity · GitHub

Though it’s not the most specific, so the following code will likely run a lot more often than you would like it to:

#if UNITY_EDITOR
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

[InitializeOnLoad]
public static class ComponentNameEnforcer
{
	static ComponentNameEnforcer()
	{
		ObjectChangeEvents.changesPublished += HandleChangesPublished;
	}

	private readonly static List<Component> _componentsCache = new();

	private static void HandleChangesPublished(ref ObjectChangeEventStream stream)
	{
		int length = stream.length;
		for (int i = 0; i < length; i++)
		{
			var eventType = stream.GetEventType(i);

			if (eventType == ObjectChangeKind.ChangeGameObjectStructure)
			{
				stream.GetChangeGameObjectStructureEvent(i, out var data);
				EnforceComponentNames(data.instanceId);
			}

			if (eventType == ObjectChangeKind.ChangeGameObjectOrComponentProperties)
			{
				stream.GetChangeGameObjectOrComponentPropertiesEvent(i, out var data);
				EnforceComponentNames(data.instanceId);
			}
		}
	}

	private static void EnforceComponentNames(int instanceID)
	{
		var gameObject = EditorUtility.InstanceIDToObject(instanceID) as GameObject;
		if (gameObject == null)
		{
			return;
		}

		gameObject.GetComponents<Component>(_componentsCache);
		foreach (var component in _componentsCache)
		{
			var serialisedObject = new SerializedObject(component);
			var nameProperty = serialisedObject.FindProperty("m_Name");
			if (nameProperty != null)
			{
				nameProperty.stringValue = gameObject.name;
			}
			serialisedObject.ApplyModifiedProperties();
			serialisedObject.Dispose();
		}

		_componentsCache.Clear();
	}
}
#endif

Particularly ObjectChangeKind.ChangeGameObjectOrComponentProperties, which changes whenever any property on a game object changes, including anything in a component inspector. Though that’s the only way to capture when a game object’s name changes.

7

Yup, that seems to be working albeit for custom components only. Unity components (like Rigidbody2D or Animator) seem to not raise this event.

I did add a slight modification, since the instanceID reported in ChangeGameObjectStructureEventArgs can refer to a Component, not just a GameObject and I wanted the component type to be written into m_Name:

#if UNITY_EDITOR
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

[InitializeOnLoad]
public static class ComponentNameEnforcer
{
	static ComponentNameEnforcer()
	{
		ObjectChangeEvents.changesPublished += HandleChangesPublished;
	}

	private static readonly List<Component> ComponentsCache = new();

	private static void HandleChangesPublished(ref ObjectChangeEventStream stream)
	{
		var length = stream.length;
		for (var i = 0; i < length; i++)
		{
			var eventType = stream.GetEventType(i);

			if (eventType == ObjectChangeKind.ChangeGameObjectStructure)
			{
				stream.GetChangeGameObjectStructureEvent(i, out var data);
				EnforceComponentNames(data.instanceId);
			}

			if (eventType == ObjectChangeKind.ChangeGameObjectOrComponentProperties)
			{
				stream.GetChangeGameObjectOrComponentPropertiesEvent(i, out var data);
				EnforceComponentNames(data.instanceId);
			}
		}
	}

	private static void EnforceComponentNames(int instanceID)
	{
		var goOrObject = EditorUtility.InstanceIDToObject(instanceID);
		if (goOrObject is GameObject go)
		{
			go.GetComponents(ComponentsCache);
		}
		else if (goOrObject is Component comp)
		{
			ComponentsCache.Add(comp);
		}
		else
		{
			return;
		}

		foreach (var component in ComponentsCache)
		{
			var serialisedObject = new SerializedObject(component);
			var nameProperty = serialisedObject.FindProperty("m_Name");
			if (nameProperty != null)
			{
				nameProperty.stringValue = component.GetType().Name;
			}

			serialisedObject.ApplyModifiedProperties();
			serialisedObject.Dispose();
		}

		ComponentsCache.Clear();
	}
}
#endif

It’s partially what I needed. Thank you @spiney199 for helping out!

1 Like