Upgrade guide change - `NavigationException` removal

[ilonatommy]

PR: #61306.
Released in: 10.0.0-preview4.

Change description

Previously:

• NavigationManager.Redirect in SSR was throwing an internal exception, interrupting the call stack execution.
• Consequences: no code after the redirection would be reached and wrapping the redirection call into a try-catch could catch the internal exception, breaking the redirection mechanism.

Currently:

• NavigationManager.Redirect in SSR rises a redirection event that the renderer is subscribed to. Code execution flow is uninterupted.
• Consequences: code after redirection is executed.

Fallback to the previous way of working:

AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.NavigationManager.EnableThrowNavigationException", isEnabled: true);

@guardrex

[guardrex]

It was resolved in the docs on dotnet/AspNetCore.Docs#34892.

However, the bit on the AppContext switch isn't covered. Do you want to cover it? I'd have to add a section to the Routing article because we never described the implementation details of how the redirect behavior worked internally.

[ilonatommy]

Don't we have a separate document that would contain the change log in the context of upgrading the app? This is a breaking change. I had a feeling we have a special place in docs for these.

However, the bit on the AppContext switch isn't covered. Do you want to cover it? I'd have to add a section to the Routing article because we never described the implementation details of how the redirect behavior worked internally.

Yes, please, the fallback is important.

[ilonatommy]

You know, like this https://learn.microsoft.com/en-us/aspnet/core/migration/80-90?view=aspnetcore-9.0 but for 9->10.

Edit:
I realized I called "update" instead of "upgrade", that's probably the source of confusion.

[guardrex]

Yes, that's right for our migration coverage. However, the formal breaking changes log is maintained by the .NET docs team. For .NET 10 ...

https://learn.microsoft.com/en-us/dotnet/core/compatibility/10.0

So far, there's no "ASP.NET Core" section, but you can see one for 9.0 at ...

https://learn.microsoft.com/en-us/dotnet/core/compatibility/9.0#aspnet-core

For migration, yes, I'll make a note of it in a new documentation issue for our upcoming Migration article and reference this issue. UPDATE: Done! 👍 ... dotnet/AspNetCore.Docs#35360.

WRT reference content, I don't think we described the internal behavior of the redirect in the Blazor Routing article. I'll research it and report back, probably tomorrow (Wednesday). I added an issue to get the behavior and switch covered for Pre4 ... dotnet/AspNetCore.Docs#35361.

[guardrex]

I confirmed that we don't describe the internal behaviors. We never mentioned the NavigationException in the first place outside of telling devs in the Movie dB tutorial how to silence the exception in VS, so I'll probably only need to add content to the WN article (and in Migration later when we reach the RC era) with Javier's summary from the PU issue of what the internal behavior was, is going to be, and how to fall back with the AppContext switch.

The issues are open and cross-linked into .NET 10 docs tracking and the Blazor.Docs project "10.0" column, so they won't get lost.

... and I've just noted that it will be for P5.

[danroth27]

We'll need to provide specific guidance on how to update the IdentityRedirectManager from the Blazor Web App template when Individual Accounts auth is enabled. The IdentityRedirectManager previously through an InvalidOperationException after the call to RedirectTo to ensure the method wasn't being called from an interactive render mode and all the redirection methods were marked with [DoesNotReturn]. Users that currently have this code in their apps will need to remove the InvalidOperationException and the [DoesNotReturn] attributes.

[guardrex]

The last point ☝ is covered here ...

https://learn.microsoft.com/en-us/aspnet/core/release-notes/aspnetcore-10.0?view=aspnetcore-9.0#navigationmanagernavigateto-no-longer-throws-a-navigationexception

... and will go into migration guidance when we generate it in the RC time frame (that's when we normally do it due to framework feature churn).