Provide full `updateTypes` to MetadataUpdateHandlers

[jeromelaban]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Using Hot Reload should provide the updated types that the HotReload workspace is generating. At present time, the browserlink integration does not fill the updatedTypes parameter properly when deltas are sent.

The aspnetcore-browser-refresh.js contains this:

    let applyError = undefined;
    if (window.Blazor?._internal?.applyHotReload) {
      // Only apply hot reload deltas if Blazor has been initialized.
      // It's possible for Blazor to start after the initial page load, so we don't consider skipping this step
      // to be a failure. These deltas will get applied later, when Blazor completes initialization.
      deltas.forEach(d => {
        try {
          window.Blazor._internal.applyHotReload(d.moduleId, d.metadataDelta, d.ilDelta, d.pdbDelta)
        } catch (error) {
          console.warn(error);
          applyError = error;
        }
      });
    }

And while d.updatedTypes exists, this member is not passed to window.Blazor._internal.applyHotReload:

Expected Behavior

updatedTypes should not be empty when a type member is hot reloaded in Visual Studio.

Steps To Reproduce

Add the following to a blazor webassembly app:

   [assembly:MetadataUpdateHandler(typeof(MyHandler))]

    static class MyHandler
    {
        static void ClearCache(Type[]? updatedTypes)
        {
            Console.WriteLine("ClearCache: " + string.Join(",", updatedTypes.Select(t => t.ToString())));

        }
        static void UpdateApplication(Type[]? updatedTypes)
        {
            Console.WriteLine("UpdateApplication: " + string.Join(",", updatedTypes.Select(t => t.ToString())));
        }
    }

Exceptions (if any)

None.

.NET Version

8.0.100

Anything else?

It is likely that such a change will require:

aspnetcore/src/Components/WebAssembly/WebAssembly/src/HotReload/WebAssemblyHotReload.cs

Line 46 in 4b78107

public static void ApplyHotReloadDelta(string moduleIdString, byte[] metadataDelta, byte[] ilDelta, byte[] pdbBytes)

To be updated to use updatedTypes in the same fashion that dotnet/sdk uses it:

https://github.com/dotnet/sdk/blob/50ccc948eb082d316158b709301b28c5e7f60c01/src/BuiltInTools/DotNetDeltaApplier/HotReloadAgent.cs#L230

Thanks for contacting us.

We're moving this issue to the .NET 9 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.