SDK Bug & Feature Requests

The UdonBehaviour[] (Array) variable cannot be resolved and used in UdonGraph.

Currently, UdonSharp does not recognize Version Defines, so we can't switch the script code based on version defines. When we distribute asset that integrate with external VPM/UPM assets, Version Defines allow us to flexibly adapt our asset to breaking changes and new features of external assets. Otherwise, we would have to split it into a separate script or package, or drop support for older versions. Related Links: https://github.com/vrchat-community/UdonSharp/issues/85 https://feedback.vrchat.com/feature-requests/p/add-assembly-version-defines-support

If you run "Build & Test" and the world build fails, the client/s still start. I don't think this makes much sense, because an old build is ran. This is confusing and if someone misses the build error they will proceed to waste time checking/testing an old build. There are other options for testing the last build and they use the wording of "last build" clearly, so this one shouldn't do that.

If a upm package is added using a directory outside of the project root, and then you attempt to create a U# script inside of that external package, an exception is thrown and the asset file is not created. This is because UdonSharpBehaviourEditor fails to convert the absolute path to an AssetDatabase path in this situation. Instead of using EditorUtility.SaveFilePanel and then trying to make it into a relative path, it should be using EditorUtility.SaveFilePanelInProject.

Many junk udon exceptions are logged in the editor because OnDisable events are called in UdonBehaviour when the editor scene is unloading while leaving play mode. The object destruction order isn't defined, which leads to many issues: * The Networking.LocalPlayer may be null (something that cannot happen in game) * Player data persistence may have already been destroyed * Random sibling objects used by behaviours may have already been destroyed * The UdonManager may have already been destroyed (which is really bad, because if it's used, for instance by calling SendCustomEventDelayedFrames, it constructs a new instance and unity complains that new objects appears during the teardown process. Also, when the new second instance of UdonManager is created, it recreates all the PrimitiveType[] primitiveTypes too) tl;dr: At least in the editor, UdonBehaviour.RunEvent shouldn't be executed if EditorApplication.isPlayingOrWillChangePlaymode is false.

https://creators.vrchat.com/releases/release-3-10-3 Attached and depicted is the same avatar in SDK 3.10.2 and 3.10.3. The avatar in SDK 3.10.3 shows additional warnings about particle systems which emit dynamic lights (matching the server-side validation behavior that was also the case with 3.10.1 and earlier), but there's no mention in the release notes (above) that the SDK will now warn about this.

UdonSharp components set the hideFlags of their backing UdonBehaviour to HideInInspector within OnEnable, which is unsafe and causes the inspector to reflow improperly. It should delay the hideFlags change until the next frame using an EditorApplication.delayCall.

I Hello VRChat Support, I’m reporting a reproducible avatar upload issue that persists even in a clean environment. Summary of the issue I am encountering all of the following in the same upload flow: Image upload fails with: You must upload a valid image! Capture From Scene does not work. Upload appears to proceed but the resulting avatar record is corrupted: only the avatar name and description remains other avatar data appears empty/missing in-game the avatar appears as an error fallback avatar. Environment OS: Windows 11 Unity: 2022.3.22f1 VRChat SDK: Latest via VCC CPU: AMD Ryzen 9 9900X GPU: NVIDIA GeForce RTX 5070 Ti RAM: 32GB Motherboard: B650 AORUS ELITE V2 Project path used for testing: D:/projects/VRChat What I already tested I have already completed and re-checked all common troubleshooting steps: Reinstalled Unity / VCC / VRChat SDK Cleared Unity, VRChat, cache/temp files Verified clean ASCII-only project path Tested valid image formats/sizes/import settings Tested both Capture In Scene and Select Image Tested with a brand-new clean avatar project (same issue) Disabled IPv6 Tested with 1.1.1.1/WARP Disabled security/network filtering software during tests Rechecked graphics-side settings and driver state Despite all of the above, the issue remains reproducible. Log behavior .vrca upload appears to complete failure occurs during/after image upload validation server returns HTTP 400 with You must upload a valid image! upload does not fully fail immediately but results in a corrupted avatar record Time window (UTC) 2026-04-23, approximately 16:17–16:19 UTC Request IDs from logs mobosea9lcl12lms moboselqww7s0yy2 moboscxcopkb73lm mobos8bvujuri33b mobosfaprk058ofd mobosg29z490ju1q (Additional request IDs are included in the attached log.) Attachments Cleaned editor log (non-essential lines removed, relevant upload flow preserved) Reproduction video (YouTube), including: Capture From Scene failure Select Image preview visible, but image upload failure local upload abnormal behavior resulting avatar becoming name-only/empty in-game error fallback avatar task Manager visible throughout the entire video https://www.youtube.com/watch?v=u1NzwbQ12FQ Please investigate backend image validation and avatar record consistency for this upload flow using the attached logs, video, timestamps, and request IDs. Thank you for your help.

OnVRCSDKBuildRequested should return false in the catch. OnPreprocessAvatar already does this, but it seems that it was missed in OnVRCSDKBuildRequested.

If a persistence update happens two frames in a row, it can attempt to write the persistence file twice at the same time, throwing a file lock error. SaveToFile needs to store an isWriting state, and LateUpdate should short circuit if a write is already in progress (it'll just get picked up again on the next frame).