Spine-Unity 4.1 read 4.1-from-4.2-from-4.3.08 skeleton json throw Error.

ZhengHua

Hello Spine Team,

I am currently experiencing some issues and would appreciate your assistance.

As a Unity engineer, I do not personally use the Spine Editor. Consequently, I may not be able to provide comprehensive details regarding the editor settings. If any specific editor-related information is required to diagnose and resolve this issue, please let me know, and I will request it from my team members.

Please accept my apologies for any phrasing issues; as my English is limited, I am translating my text line by line. I hope this does not cause any difficulties in understanding.

My team members recently updated the Spine Editor to version 4.3.08 and exported the skeleton JSON files using this new version. However, since the Spine-Unity Runtime version on the programming side is still 4.1, we are unable to read or load these new files successfully.

Since upgrading our Spine-Unity Runtime from 4.1 to 4.3 would require a massive amount of refactoring and adjustments across our entire game codebase, we are trying to avoid a runtime upgrade if possible.

To resolve this, I asked my team members to set the version to 4.1 when exporting the JSON files from the 4.3.08 Editor, and we made sure to check the "Nonessential data" option as suggested by the forum guides.

However, this workaround did not solve the issue. The export still seems incompatible; the corresponding SkeletonDataAsset in Unity still throws errors and fails to load.

Could you please advise us on how to properly handle this situation? What is the recommended workflow to successfully downgrade or adapt these files so they can be read by the 4.1 Runtime without upgrading our codebase?

Problem statement

1) What I have tried:

I asked my team members to export the skeleton JSON from the Spine Editor by selecting version 4.1 and ensuring that the "Nonessential data" option was checked.
We then attempted to reimport and reload these new JSON files into our Unity project using the 4.1 Runtime.
However, the SkeletonDataAsset threw an error, stating that it cannot correctly read or access the downgraded JSON file.

2) What I expected:
I expect the SkeletonDataAsset to successfully read and process the downgraded skeleton JSON file without any errors.

3) What actually happened:
SkeletonDataAsset throw error message.

4 ) Side Note
I attempted a temporary workaround by directly editing the skeleton JSON file. Inside the file, I manually changed the line "spine":"4.1-from-4.2-from-4.3.08" to "spine":"4.1". After making this manual modification, the SkeletonDataAsset actually loaded perfectly in Unity without throwing any errors.

However, since I am uncertain whether this manual hack will introduce unexpected bugs, visual glitches, or data corruption during runtime animation playback, I wanted to consult you on the forum. Is this a safe approach, or is there a proper workflow we should follow instead?

Reproducing the problem

Export the animation from the 4.3 Editor while setting the export version designation to 4.1.
Attempt to load the exported files into a SkeletonDataAsset in Unity.

Runtime information

Tell us your Spine Runtimes version.
spine-unity-4.1-2024-06-19

Post your entire error messages here (or attach them), if you got any error messages.

Failed to read version info at skeleton '刺蝟小兵'. It is likely not a valid Spine SkeletonData file.
System.FormatException: Input string was not in a correct format.
  at System.Number.ThrowOverflowOrFormatException (System.Boolean overflow, System.String overflowResourceKey) [0x0001a] in <1071a2cb0cb3433aae80a793c277a048>:0 
  at System.Number.ParseInt32 (System.ReadOnlySpan`1[T] value, System.Globalization.NumberStyles styles, System.Globalization.NumberFormatInfo info) [0x00016] in <1071a2cb0cb3433aae80a793c277a048>:0 
  at System.Int32.Parse (System.String s, System.IFormatProvider provider) [0x00017] in <1071a2cb0cb3433aae80a793c277a048>:0 
  at Spine.Unity.SkeletonDataCompatibility.GetVersionInfo (UnityEngine.TextAsset asset, System.Boolean& isSpineSkeletonData, System.String& problemDescription) [0x001a0] in C:\Unity\CatCoffeeBar\Assets\Spine\Runtime\spine-unity\Asset Types\SkeletonDataCompatibility.cs:153 
UnityEngine.Debug:LogError (object,UnityEngine.Object)
Spine.Unity.Editor.AssetUtility:ImportSpineContent (string[],System.Collections.Generic.List`1<string>,bool) (at Assets/Spine/Editor/spine-unity/Editor/Utility/AssetUtility.cs:375)
Spine.Unity.Editor.SkeletonDataAssetInspector:DoReimport () (at Assets/Spine/Editor/spine-unity/Editor/Asset Types/SkeletonDataAssetInspector.cs:698)
Spine.Unity.Editor.SkeletonDataAssetInspector:OnInspectorGUI () (at Assets/Spine/Editor/spine-unity/Editor/Asset Types/SkeletonDataAssetInspector.cs:240)
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)

Nate

Thank you for your detailed post!

ZhengHua Please accept my apologies for any phrasing issues; as my English is limited, I am translating my text line by line.

You are welcome to post in your native language, our forum translates automatically so everyone sees all posts in their own language. If you see my post in English, you can change the language here:
https://esotericsoftware.com/site-language

ZhengHua As a Unity engineer, I do not personally use the Spine Editor.

FWIW, if needed, you can run the Spine trial and open projects just to see them.

ZhengHua I asked my team members to set the version to 4.1 when exporting the JSON files from the 4.3.08 Editor, and we made sure to check the "Nonessential data" option as suggested by the forum guides.

This is not recommended. Exporting to an older JSON version is for rescue only. Newer versions have newer features and exports from newer versions cannot fully work the same for older versions. There also may be small differences in behavior.

ZhengHua I manually changed the line "spine":"4.1-from-4.2-from-4.3.08" to "spine":"4.1". After making this manual modification, the SkeletonDataAsset actually loaded perfectly in Unity without throwing any errors.

This bypasses the safety check, but you should not rely on the downgraded export to work correctly. It needs to be imported into the old version and checked for data loss or behavior changes. The only safe way is to import into the old version and then export from that old version. That guarantees you have JSON that is fully compatible with the old runtimes.

If you upgrade your editor to 4.3, you must upgrade your runtimes to 4.3. There is no alternative. Always keep your runtimes and editor versions synchronized. See:
https://esotericsoftware.com/spine-versioning#Synchronizing-versions

ZhengHua upgrading our Spine-Unity Runtime from 4.1 to 4.3 would require a massive amount of refactoring and adjustments across our entire game codebase, we are trying to avoid a runtime upgrade if possible.

Sorry, but this is the only way. You can either move animators back to 4.1, or move your runtime to 4.3. Anything else will not work well.

If animators have not done work in 4.3, you can have them go back to the 4.1 versions of their project files. That is safest way to go back to 4.1. If they have done work, you can use 4.3 to export 4.1 JSON, import that into 4.1, check the skeletons and animations for errors and data loss, then save a 4.1 project file and use that to export for 4.1 runtimes. Your animators would then continue using 4.1.

However, I suggest moving your runtimes to 4.3. The code changes require some work but it is worth the trouble for new 4.3 features and better performance.

The 4.3 API changed more than most releases, but the code changes required are mostly mechanical. For example, instead of the local and world transforms being directly on Bone, the Bone has poses. Usually you want to use bone.appliedPose, which is a BonePose and has the transform values you are used to. So instead of bone.worldX use bone.appliedPose.worldX.

There is a little more to it if you are doing something advanced, but it shouldn't be too hard. We are here to help if you have any questions. Unfortunately the documentation is not yet complete for 4.3.

ZhengHua

十分感謝你 Nate.

我們的動畫師已經有在新版本更新過動畫了，所以應該是沒辦法再使用舊版本來開啟檔案了。

他本人也有嘗試過使用舊版的 Spine Editor 開啟動畫，但會無法正常打開。

我們團隊會再協調怎麼同步 Spine 版本的問題。

再次感謝你們這麼迅速地回復此問題。

Harald

ZhengHua Our animator has already updated the animation in the new version, so we probably can’t use the old version to open the file anymore.

He also tried using an older version of the Spine Editor to open the animation, but it would not open properly.

Sorry to hear you're encountering problems!

Did you export from Spine Editor 4.3 with Export settings set to "Data" "JSON" and "Version" set to "4.1" and then try to open in Spine Editor version 4.1 via "Import Data ..."? Please note that you can't directly open a 4.3 Spine project in Spine Editor version 4.1.

If it fails to open in Spine Editor 4.1 when exported from 4.3. with "Version" "4.1", you could have a try to first export from 4.3 as "Version" "4.2", then import it Spine 4.2 and re-export from there with setting "Version" "4.1".