Question [Platform 0.9.0] Loading Entity (Sub)Scene failed because the entity header file couldnt be resolved

Hello,
I run into trouble with subscenes since I updated some packages: "Loading Entity (Sub)Scene failed because the entity header file couldn't be resolved."

Spoiler: manifest.json for Unity 2020.2.0b10

{
"dependencies": {
"com.unity.burst": "1.3.7",
"com.unity.collab-proxy": "1.3.9",
"com.unity.collections": "0.14.0-preview.16",
"com.unity.entities": "0.14.0-preview.19",
"com.unity.ide.rider": "2.0.7",
"com.unity.ide.visualstudio": "2.0.5",
"com.unity.ide.vscode": "1.2.3",
"com.unity.netcode": "0.5.0-preview.5",
"com.unity.physics": "0.4.1-preview",
"com.unity.platforms.android": "0.9.0-preview.9",
"com.unity.platforms.linux": "0.9.0-preview.9",
"com.unity.platforms.windows": "0.9.0-preview.9",
"com.unity.render-pipelines.universal": "10.1.0",
"com.unity.rendering.hybrid": "0.10.0-preview.21",
"com.unity.scriptablebuildpipeline": "1.9.0",
"com.unity.searcher": "4.3.1",
"com.unity.shadergraph": "10.1.0",
"com.unity.test-framework": "1.1.18",
"com.unity.test-framework.performance": "2.3.1-preview",
"com.unity.textmeshpro": "3.0.3",
"com.unity.timeline": "1.4.4",
"com.unity.ui": "1.0.0-preview.11",
"com.unity.ui.builder": "1.0.0-preview.9",
"nuget.mono-cecil": "0.1.6-preview",
"com.unity.modules.ai": "1.0.0",
"com.unity.modules.androidjni": "1.0.0",
"com.unity.modules.animation": "1.0.0",
"com.unity.modules.assetbundle": "1.0.0",
"com.unity.modules.audio": "1.0.0",
"com.unity.modules.cloth": "1.0.0",
"com.unity.modules.director": "1.0.0",
"com.unity.modules.imageconversion": "1.0.0",
"com.unity.modules.imgui": "1.0.0",
"com.unity.modules.jsonserialize": "1.0.0",
"com.unity.modules.particlesystem": "1.0.0",
"com.unity.modules.physics": "1.0.0",
"com.unity.modules.physics2d": "1.0.0",
"com.unity.modules.screencapture": "1.0.0",
"com.unity.modules.terrain": "1.0.0",
"com.unity.modules.terrainphysics": "1.0.0",
"com.unity.modules.tilemap": "1.0.0",
"com.unity.modules.ui": "1.0.0",
"com.unity.modules.uielements": "1.0.0",
"com.unity.modules.umbra": "1.0.0",
"com.unity.modules.unityanalytics": "1.0.0",
"com.unity.modules.unitywebrequest": "1.0.0",
"com.unity.modules.unitywebrequestassetbundle": "1.0.0",
"com.unity.modules.unitywebrequestaudio": "1.0.0",
"com.unity.modules.unitywebrequesttexture": "1.0.0",
"com.unity.modules.unitywebrequestwww": "1.0.0",
"com.unity.modules.vehicles": "1.0.0",
"com.unity.modules.video": "1.0.0",
"com.unity.modules.vr": "1.0.0",
"com.unity.modules.wind": "1.0.0",
"com.unity.modules.xr": "1.0.0"
}
}

Somehow it cannot load the subscene properly. It does not work with Unity 2020.2.0b10/11, but it works with Unity 2021.1.0a2/4, but only in the editor. Running it with a platform build for windows/android using the newest package 0.9.0, it still throws an error ("could not open file .../StreamingAssets/SubScenes/xxx.entityheader subscenes for read").

(This leads also to a Netcode problem, since a entity in the subscene gets not converted, which should have the component GhostPrefabCollectionComponent, needed in GoInGameServerSystem.cs)

 

do you have uitoolkit in your project? might be related to something I encountered
1279934 https://issuetracker.unity3d.com/is...hen-ui-toolkit-package-is-included-in-project

I seem to recall something about entity headers missing(though that report doesnt mention it specifically)

 

Thanks @thelebaron, that's it!
How did you find out? I'm so angry about myself that I can't read stacktraces properly -.- I just saw this entity header message and was lost for hours without clue how to continue...

 

I cant read those stacktraces either but usually after losing a bit sanity & deleting the library and other bog standard attempts to fix the issue, i make a packages only project to test for errors and(assuming there are errors with just the packages) go through the tedium of removing packages to see which one is the culprit

 

Is this issue fixed for real? I'm getting

using 1.0.0-preview.14, with 2020.3.6f1, build and run. Or is a repro?

 

No it's not there is a whole thread in the ui forum about it. There are very simple steps to reproduce yet Unity can't seem to reproduce it. It's very frustrating...
On a side note from my last testing it does not happen with unity 2021... Which does not help much given the warning in the forum about dots/2021 compatibility...

 

Yeah, totally..

 

I think I managed to get it fixed, which caused by `SubScene` integrated with `UIToolKit(specifically 1.0.0-preview.14)` when building.

The key is: Subscenes will not be built properly while UIToolKit is installed.(and Unity will give an error log while building)


So you just have to build subscenes without UIToolKit, fortunately you will find new building subscene header is exactly the same subscene header that Unity build and run console report missing, then you manually put these headers back where they came from after you built subscenes with UIToolKit.



Here's what I do:
1. Backup my proper built subscene headers(Unity project\Builds\WindowsClassicBuildConfiguration\Project Name_Data\StreamingAssets\SubScenes).
2. Get UIToolKit back online, click build and wait is done.
3. Check out what subscene headers are missing and get them from previous backup subscenes to `\SubScenes` file.
4. Click run.

Now `SubScene` and `UIToolKit can finally build and run together.(I will edit again if anything goes up)