Question How to Catch Addressables AsyncOperation download errors

Hello,
I mark whole scene as addressable and I use this code to download and load scene from server.
Scene is about 30mb.

Code (CSharp):

1. AsyncOperationHandle ao = Addressables.LoadSceneAsync(scene1, UnityEngine.SceneManagement.LoadSceneMode.Single);
2.  

As say user's mobile have lost the internet connection during download or at the beginning.

In this case Addressable throw the exception " Scene 'Assets/Scenes/Level2.unity' couldn't be loaded because it has not been added to the build settings or the AssetBundle has not been loaded."

This means that game freezes and need to be restarted again. I can't show any message to user that an error has occurred.

The questions is how to handle Addressable downloading errors ?

"Completed+=" event don't work because error occurs before it fired so I can not check AsyncOperationHandle Status.

I can check internet connection before user start downloading but I need better way was to catch Addressable exceptions when they are throws

Please advice
Thank you

 

I use 1.8.4 and Unity 2019.4

 

ok I will report it

 

Is there any known workaround to find out if a request has failed in this way?

P.S. If not, is there a bug report to track?

Thanks

 

Any updates on this please?

 

I've same problem. I can't handler error downloading/loading with Addressables.LoadSceneAsync. Have you some suggestion on solution?

 

The problem still persists in the Addressables 1.17.17.
The ".Completed" handler simply not called if the asset bundle containing the scene is failed to load (in any case: any HTTP error, or no Internet connection). The only two cases when the handler is called are: if the loading succeeded and if the resource key is invalid.

That's SO ANNOYING that Addressables has so many bugs and is so unstable.

 

I've spent all the day long chasing this bug and have found the root of the problem. I've sent a bug report to Unity Technologies and for those who need the fix urgently here is the explanation and the solution.

1. What is the problem:

In the behaviour of SceneManager.LoadSceneAsync() is broken. If a Scene requested to load is not available, the method will return null instead of AsyncOperationHandle.

This crashes Addressables.LoadSceneAsync(), specifically - SceneProvider.cs in method void IUpdateReceiver.Update(float unscaledDeltaTime) because the value of m_Inst.m_Operation happens to be null. Which leads to handle.Completed handler never called and app being stuck (there is no way to avoid this or handle the exception from outside). The only solution as of now is to patch SceneProvider.cs of Addressables manually to handle null result there.

Moreover, the documentation here clearly says that SceneManager.LoadSceneAsync() doesn't return null because the example given there assumes that the result of SceneManager.LoadSceneAsync() is never null:
https://docs.unity3d.com/ScriptReference/SceneManagement.SceneManager.LoadSceneAsync.html

Even more, it is said in docs that invalid scene name will cause an Exception to be thrown. None happens. Just an error is logged to the console.

2. What can be done.
We can't change the SceneManager.LoadSceneAsync(), but we can fix SceneProvider.cs a little bit to make it handle the null result. Thee are two options:
- change the original file;
- create a fixed copy of SceneProvider.cs and register it in Addressables settings.

We have to fix two methods:

2.1. void IUpdateReceiver.Update(float unscaledDeltaTime):

Code (CSharp):

1.             void IUpdateReceiver.Update(float unscaledDeltaTime)
2.             {
3.                 if (m_Inst.m_Operation.isDone || (!m_Inst.m_Operation.allowSceneActivation && m_Inst.m_Operation.progress == .9f))
4.                 {
5.                     m_ResourceManager.RemoveUpdateReciever(this);
6.                     Complete(m_Inst, true, null);
7.                 }
8.             }
9.  

Change it this way:

Code (CSharp):

1.             void IUpdateReceiver.Update(float unscaledDeltaTime)
2.             {
3.                 // fix start
4.                 if (m_Inst.m_Operation == null)
5.                 {
6.                     m_ResourceManager.RemoveUpdateReciever(this);
7.                     Complete(m_Inst, false, "The AsyncOperationHandle is null for Scene loading.");
8.                     return;
9.                 }
10.                 // fix end
11.  
12.                 if (m_Inst.m_Operation.isDone || (!m_Inst.m_Operation.allowSceneActivation && m_Inst.m_Operation.progress == .9f))
13.                 {
14.                     m_ResourceManager.RemoveUpdateReciever(this);
15.                     Complete(m_Inst, true, null);
16.                 }
17.             }
18.  

2.2. internal SceneInstance InternalLoadScene(IResourceLocation location, bool loadingFromBundle, LoadSceneMode loadMode, bool activateOnLoad, int priority)

Code (CSharp):

1.             internal SceneInstance InternalLoadScene(IResourceLocation location, bool loadingFromBundle, LoadSceneMode loadMode, bool activateOnLoad, int priority)
2.             {
3.                 var internalId = m_ResourceManager.TransformInternalId(location);
4.                 var op = InternalLoad(internalId, loadingFromBundle, loadMode);
5.  
6.                 op.allowSceneActivation = activateOnLoad;
7.                 op.priority = priority;
8.  
9.                 return new SceneInstance() { m_Operation = op, Scene = SceneManager.GetSceneAt(SceneManager.sceneCount - 1) };
10.             }
11.  

The fixed code:

Code (CSharp):

1.             internal SceneInstance InternalLoadScene(IResourceLocation location, bool loadingFromBundle, LoadSceneMode loadMode, bool activateOnLoad, int priority)
2.             {
3.                 var internalId = m_ResourceManager.TransformInternalId(location);
4.                 var op = InternalLoad(internalId, loadingFromBundle, loadMode);
5.  
6.                 if (op != null)
7.                 {
8.                     op.allowSceneActivation = activateOnLoad;
9.                     op.priority = priority;
10.                 }
11.                 return new SceneInstance() { m_Operation = op, Scene = SceneManager.GetSceneAt(SceneManager.sceneCount - 1) };
12.             }
13.  

I tested everything with these versions:
Unity 2019.4.10f1
Addressables 1.17.17

 

Any official fix or solution from Unity side?? @unity_bill and @TreyK-47

 

tangential problem involving DownloadDependenciesAsync it looks like if the underlying web operations fail, the AsyncOperationHandle.Status is AsyncOperationStatus.Failed upon completion (after either an await or in a completion handler). If LoadSceneAsync behaves similarly, then checking for that will at least give you an indicator. What you do from there if Unity refuses to load your assets because they e.g. take more than 3 seconds to download and curl gives up... is probably on you.

 

For anyone that stumbles across this from google like I did - you can kinda handle this using the ResourceManager.ExceptionHandler. You'll still see the NullReferenceException happen in the logs, but it'll at least allow you to manage the fact that you can't get your addressable scene via the Exception that is a parameter in your CustomExceptionHandler.

 

@ekodl thanks. that worked

just modified it to catch the specific "could not connect to remote bundle" error as a normal log and all others as warnings

Code (CSharp):

1. void CustomExceptionHandler(AsyncOperationHandle handle, Exception exception)
2. {
3.     if (exception.HResult == -2146233088)
4.     {
5.         Debug.Log("AA: Connection failed to load remote bundles ");
6.     }
7.     else
8.     {
9.         Debug.LogWarning("Unhandled Error + " +exception.Message);
10.     }
11. }

Its more readable for us like this

 

Just ran in to this my self in 1.18.19. Has this issue been addressed in 1.19?

 

Never mind. This issue seems to be fixed in 1.19.18.

 

Hi @pillakirsten. I still quite confusing about how I have to handle Addressables download error.
I'm trying to use ResourceManager.ExceptionHandler solution which you mentioned earlier, but the only thing I've got its a regular log message. I currently use a workaround, I subscribe on Application.logMessageReceived event and parse every single log message, trying find the message which starts from "Web request failed to load..." but it's avery bad solution

I'm using Unity 2022.3.4f1 with Addressables 1.21.14. Also I use Unity's CCD solution

Web request failed to load from cache. The cached AssetBundle will be cleared from the cache and re-downloaded. Retrying...

ProtocolError : HTTP/1.1 404 Not Found

ResponseCode : 404, Method : GET

url : {here-is-my-url}

And it's not only about scenes, I've got the same behaviour with other groups

 

Same problem, Is there any new update?

Our project is using Unity 2021.1.16 and Addressable 1.21.14 (upgraded by manijson from 1.19.19)
Each we upload a new build version to the host, Addressable will try to load max 3 times with the error log same below:

cacheVersion=1692583293864Dj9HFYwgyg:3 Web request failed, retrying (2/3)...
ConnectionError : Request timeout
ResponseCode : 500, Method : GET