IndexOutOfRangeException in Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ExtraFeatureSet

[zlatanov]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Sometimes we get the following error logged:

IndexOutOfRangeException: Index was outside the bounds of the array.
    at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.ExtraFeatureSet(Type key, Object value)
    at Microsoft.AspNetCore.ResponseCompression.ResponseCompressionMiddleware.InvokeCore(HttpContext context)

Looking at the code there, I can't find anything that would cause this error if the code there is not accessed concurrently. Is it possible that, if a connection is aborted while for example the ResponseCompressionMiddleware is being executed, that this ExtraFeatureSet might get executed concurrently?

Expected Behavior

No exception to occur.

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

8.0.2

Anything else?

No response

[gfoidl]

Out of curiosity: can you reproduce the same error when using Kestrel instead of IIS? (because the code for ExtraFeatureSet is the same)

[zlatanov]

Out of curiosity: can you reproduce the same error when using Kestrel instead of IIS? (because the code for ExtraFeatureSet is the same)

No, the error happens very rarely and only in production.