Blazor server page route template "catch-all" gives error in case of double asterisk in the pattern

[test-test-test14]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

In Blazor Server if in the standard project template I add a catch-all route with a double asterisk (eg. @page "/foo/{**path}") the error "Object reference not set to an instance of an object." appears when I execute the program.

Expected Behavior

No error should appear. The "catch-all" double asterisk explaination is present in https://learn.microsoft.com/en-us/aspnet/core/fundamentals/routing?view=aspnetcore-6.0 (section "Route templates" - round-trip path separator characters).

Steps To Reproduce

Create a new Blazor Server project, then in "Pages/Index.razor" under the line @page "/" add the following line:
@page "/foo/{**path}"
Then execute the program and see the exception.

Simple repro:
https://github.com/FabioPagano/testdoubleasterisk

Exceptions (if any)

Object reference not set to an instance of an object.
at Microsoft.AspNetCore.Components.Routing.Router.Refresh(Boolean isNavigationIntercepted)
at Microsoft.AspNetCore.Components.Routing.Router.d__56.MoveNext()
at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.HandleExceptionViaErrorBoundary(Exception error, ComponentState errorSourceOrNull)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasks(Task task, ComponentState owningComponentState)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.SupplyCombinedParameters(ParameterView directAndCascadingParameters)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewComponentFrame(DiffContext& diffContext, Int32 frameIndex)
at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewSubtree(DiffContext& diffContext, Int32 frameIndex)
at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InsertNewFrame(DiffContext& diffContext, 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.ComputeDiff(Renderer renderer, RenderBatchBuilder batchBuilder, Int32 componentId, ArrayRange1 oldTree, ArrayRange1 newTree)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessPendingRender()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToRenderQueue(Int32 componentId, RenderFragment renderFragment)
at Microsoft.AspNetCore.Components.ComponentBase.StateHasChanged()
at Microsoft.AspNetCore.Components.ComponentBase.CallOnParametersSetAsync()
at Microsoft.AspNetCore.Components.ComponentBase.d__20.MoveNext()
at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.HandleException(Exception exception)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.HandleExceptionViaErrorBoundary(Exception error, ComponentState errorSourceOrNull)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.AddToPendingTasks(Task task, ComponentState owningComponentState)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.SupplyCombinedParameters(ParameterView directAndCascadingParameters)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.SetDirectParameters(ParameterView parameters)
at Microsoft.AspNetCore.Components.RenderTree.Renderer.d__39.MoveNext()
at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.d__17.MoveNext()
at Microsoft.AspNetCore.Components.Rendering.HtmlRenderer.d__8.MoveNext()
at Microsoft.AspNetCore.Components.Rendering.RendererSynchronizationContext.<>c__11`1.<b__11_0>d.MoveNext()
at Microsoft.AspNetCore.Mvc.ViewFeatures.StaticComponentRenderer.d__4.MoveNext()
at Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.d__11.MoveNext()
at Microsoft.AspNetCore.Mvc.ViewFeatures.ComponentRenderer.d__6.MoveNext()
at Microsoft.AspNetCore.Mvc.TagHelpers.ComponentTagHelper.d__21.MoveNext()
at Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner.<g__Awaited|0_0>d.MoveNext()
at TestDoubleAsterisk.Pages.Pages__Host.d__7.MoveNext() in C:_eic\test\TestDoubleAsterisk\TestDoubleAsterisk\Pages_Host.cshtml:line 8

.NET Version

6.0.401

Anything else?

Microsoft Visual Studio Enterprise 2022 (64-bit) - Version 17.3.4

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.28 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.29 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.28 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.29 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.25 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.28 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.29 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.