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.

[javiercn]

I took some action here to at least capture more information on the exception to troubleshoot this better. I think this is the best we can do for now unless we are able to get a repro.

We will at least be able to see the general shape of the RenderTree and the path to the component that is being diff'ed (including the actual component) which should be enough to provide a reasonable location of where and what's happening.

[javiercn]

Moving this issue to 11 planning, but we'll take another look at it on RC2 in case we get some new data.