[WebToolsE2E][Hot Reload] Page does not update stylesheet in .NET 11 Blazor Web App with SDK 11 Preview 1

[cyimperial]

REGRESSION INFO Work with NET 10,9,8

INSTALL STEPS

1. Clean machine: Win11 x64 24h2 ENU
2. Install SDK 11 Preview 1

REPRO STEPS

1. File > New > Project > Blazor Web App > .NET 11.0 (Preview)> WASM > Global > Create.
2. Right click project > Open in terminal > run command dotnet watch
3. Open MainLayout.razor.css > Add following code to Line 5:
   background-color: gold;
4. Save the file.

Note:

• Repro on WASM and Auto.
• Doesn't repro on per page/component.
• This issue reproduces in Visual Studio but does not reproduce in Visual Studio Code.

ACTUAL
Background color of the page wasn't updating.

HotReload_bg_color.mp4

EXPECTED
Background color of the page should be updating.

[cyimperial]

Updated regression info; still reproducible on SDK 11 Preview 3.

[tmat]

@cyimperial Please always run dotnet watch --verbose and include the output in the bug description.

Dotnet watch is regenerating scoped CSS bundles and sending static asset update like so:

dotnet watch ⌚ Regenerating scoped CSS bundles.
dotnet watch 🔥 Hot reload capabilities: AddExplicitInterfaceImplementation AddFieldRva AddInstanceFieldToExistingType AddMethodToExistingType AddStaticFieldToExistingType Baseline ChangeCustomAttributes GenericAddFieldToExistingType GenericAddMethodToExistingType GenericUpdateMethod NewTypeDefinition UpdateParameters.
dotnet watch ⌚ No managed code changes to apply.
dotnet watch 🔃 [BlazorApp10 (net10.0)] Updating diagnostics.
dotnet watch 🔃 [BlazorApp10 (net10.0)] Sending static asset update request to connected browsers: 'wwwroot/BlazorApp10.Client.bundle.scp.css'.
dotnet watch 🔥 Static asset changes applied in 385ms.

Using the same dotnet watch version, if the project targets net10 it works, if it targets net11 it does not.
The issue must be in Blazor/WASM.

[artl93]

@javiercn and @SamMonoRT - can you help route?

[SamMonoRT]

cc @lewing

[lewing]

I expect this has been fixed in preview3, the current backflow pr should have all the relevant changes #53613