Hot Reload: Adding a new [Parameter] property to a components code block triggers a restart instead of applying the change at runtime

[MacdonaldRobinson]

Describe the bug

Hot Reload: Adding a new [Parameter] property to a components code block triggers a restart instead of applying the change at runtime

To Reproduce

• In WSL - Ubuntu 20.04 LTS
• Create a new web app using "dotnet new blazorwasm"
• Use "code ." to open it in VS Code
• In the Terminal type "dotnet watch"
• Open the link in the browser
• Open Shared/SurveyPrompt.razor
• Add a new parameter property to the code block called "Title2"
• Save the file
• In the console you will see the error "Unable to handle changes to /home/mac/src/blazorwasm/Shared/SurveyPrompt.razor. Do you want to restart your app - Yes (y) / No (n) / Always (a) / Never (v)?"

Expectation

Adding new parameters to a component is a very common task that should be hot reloaded

Output of dotnet --info

.NET SDK (reflecting any global.json):
Version: 6.0.100-preview.6.21355.2
Commit: 7f8e0d76c0

Runtime Environment:
OS Name: ubuntu
OS Version: 20.04
OS Platform: Linux
RID: ubuntu.20.04-x64
Base Path: /home/mac/dotnet/sdk/6.0.100-preview.6.21355.2/

Host (useful for support):
Version: 6.0.0-preview.6.21352.12
Commit: 770d630b28

.NET SDKs installed:
6.0.100-preview.6.21355.2 [/home/mac/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.0-preview.6.21355.2 [/home/mac/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.0-preview.6.21352.12 [/home/mac/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

[javiercn]

@MacdonaldRobinson thanks for contacting us.

That might be by design (although I'll let @pranavkm confirm. The reason is the same I mentioned on the previous issue, if you add or remove state from a class (fields) that causes a change on the class layout, which requires a restart.

[pranavkm]

@MacdonaldRobinson unfortunately Mono / WASM currently does not support adding custom attributes (the Parameter). This is being tracked via dotnet/runtime#52993.

The feature works in .NET Core so this should work with Blazor Server.