Encountered unsupported frame type during diffing: None

[JamesNK]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

We have a Blazor server rendered app that we gather error info from. This error from Blazor framework shows up:

System.NotImplementedException: Encountered unsupported frame type during diffing: None
at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(DiffContext& diffContext, Int32 oldFrameIndex, Int32 newFrameIndex)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& diffContext, Int32 oldStartIndex, Int32 oldEndIndexExcl, Int32 newStartIndex, Int32 newEndIndexExcl)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(DiffContext& diffContext, Int32 oldFrameIndex, Int32 newFrameIndex)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& diffContext, Int32 oldStartIndex, Int32 oldEndIndexExcl, Int32 newStartIndex, Int32 newEndIndexExcl)
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForFramesWithSameSequence(DiffContext& diffContext, Int32 oldFrameIndex, Int32 newFrameIndex)
   at Microsoft.AspNetCore.Components.RenderTree...

This error occured about 50 times in the last 7 days. I don't have anymore information.

There are some other issues that include this error message: https://github.com/search?q=repo%3Adotnet%2Faspnetcore+Encountered+unsupported+frame+type+during+diffing%3A+None&type=issues

Expected Behavior

Blazor framework doesn't throw internal errors.

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

No response

Anything else?

No response

[javiercn]

@JamesNK thanks for raising this up.

I think that as a starting point we need to try and generate a better error message to pinpoint where this is happening. Do you happen to be building RenderTrees "by hand" anywhere?

[JamesNK]

I don't think so: https://github.com/search?q=repo%3Adotnet%2Faspire+RenderTreeBuilder&type=code

If RenderTreeBuilder isn't used to do rendering by hand then you can search the code for whatever APIs are used to do that.

[JamesNK]

We use FluentUI which I think does render by hand: https://github.com/search?q=repo%3Amicrosoft%2Ffluentui-blazor%20RenderTreeBuilder&type=code

When I search for this problem in Google the results all come up in the context of either FluentUI or Syncfusion controls: https://www.google.com/search?q=%22Encountered+unsupported+frame+type+during+diffing%3A+None%22.

I think the NotImplementedException is logged at the same time another error is thrown. Perhaps there is a common pattern in these controls that means when an exception is thrown during rendering that causes a frame type of None to be added to Blazor.