Spine Unity modifies assets resulting in build error

pablito

Spine Unity package has SpineBuildProcessor which has custom asset postprocessor and preprocessor.
This SpineBuildProcessor tries to modify prefabs with SkeletonRenderer component on them before and after build.

We use spine in our prefab in our custom unity package and SpineBuildProcessor tries to modify it before and after build but unity doesnt allow modifying assets that are in custom packages!

This results in 2 errors for each prefab - before and then after every build. Can i disable this preprocessors? Or make it filter out objects in custom packages?

Stack trace:

Saving Prefab to immutable folder is not allowed: Packages/mycompany.mypackage/Prefabs/MyPrefab.prefab
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Spine.Unity.Editor.SpineBuildProcessor:PreprocessSpinePrefabMeshes () (at Library/PackageCache/mycompany.mypackage@044983d071/Plugins/Spine/Editor/spine-unity/Editor/Utility/SpineBuildProcessor.cs:89)
Spine.Unity.Editor.SpineBuildProcessor:PreprocessBuild () (at Library/PackageCache/mycompany.mypackage@044983d071/Plugins/Spine/Editor/spine-unity/Editor/Utility/SpineBuildProcessor.cs:59)
Spine.Unity.Editor.SpineBuildPreprocessor:UnityEditor.Build.IPreprocessBuildWithReport.OnPreprocessBuild (UnityEditor.Build.Reporting.BuildReport) (at Library/PackageCache/mycompany.mypackage@044983d071/Plugins/Spine/Editor/spine-unity/Editor/Utility/SpineBuildProcessor.cs:166)
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

Misaki

This post was originally posted in Editor but has been moved to Unity as it is a Unity related issue. Our Unity expert, Harald is on vacation at the moment, so please wait a little longer until he returns for a detailed answer.

pablito

Ok, I'm waiting for Harald eagerly 🙂 Here's tip i found:
since packages are supposed to be immutable and SpineBuildProcessor.cs modifies assets, hence it should make sure modified asset is in Assets/ folder.

So instead of: (SpineBuildProcessor.cs: 78):

var prefabAssets = AssetDatabase.FindAssets("t:Prefab");

it should be:

var prefabAssets = AssetDatabase.FindAssets("t:Prefab").Select(AssetDatabase.GUIDToAssetPath).Where(path => path.StartsWith("Assets/")

For me i need just t😛refab fix, but others might need it in all occurrences of AssetDatabase.FindAssets there 🙂

Harald

Sorry for the troubles! You can disable this optimization step on prefabs by disabling Optimize Preview Meshes in the Spine Preferences (Edit - Preferences - Spine). This setting is disabled by default in newer runtime versions to avoid any issues. If you don't see this option, you might just need to update your spine-unity runtime.

And thanks for the hint on excluding the package directory and only search Assets/. We will perform some checks (whether packages are always read-only even when they have been added via Add package from disk or added directly in Packages/) and then push a bugfix accordingly.

We have just pushed a bugfix to the 4.1 branch (it will be merged to 4.2-beta soon). It allows for local / modifyable package prefab assets to still be modified, while readonly prefabs should no longer be considered.

A new 4.1 spine-unity package is available for download here as usual:
spine-unity Download
Please let us know if the latest fix resolves the problem on your end as well. Thanks again for reporting!

Issue ticket URL for later reference:
https://github.com/EsotericSoftware/spine-runtimes/issues/2223