[Hot Reload with dotnet watch][Unstable] Create a 11.0 Blazor Web App project, update and save the .css file, and then refresh the browser, the project will revert to its previous state

[EmilyFeng97]

REGRESSION INFO Works well in 10.0.201 and 10.0.300-preview SDK
Also repro in .NET 11.0 preview 1 SDK

INSTALL STEPS

1. Clean Win11 x64 25h2 ENU
2. Install the .NET 11.0 preview 2 SDK from corhont build
3. Add feed

Platform

• Windows
• macOS
• Linux

Repro Steps

1. Open a normal Command Prompt
2. Create a Blazor Web App for Server project, and run it using dotnet watch

   dotnet new blazor -int Server -o MyBlazorServerApp
   cd MyBlazorServerApp
   dotnet watch
   

3. Press Ctrl + C to stop the dotnet watch
4. Then run it using dotnet watch again
5. Open Components/Layout/MainLayout.razor.css in Notepad, update the .page selector:

      .page {
          position: relative;
          display: flex;
          flex-direction: column;
     +   background-color: orange;
   

6. Save the change, the browser update to display the color
7. Refresh the browser, view the browser

Actual Result
The page will return to the previous state after refresh the browser.

Note:

1. This issue doesn't repro with 10.0.201 SDK(March Servicing build) and 10.0.300-preview build.
2. This issue doesn't repro Blazor WebAssembly Standalone project.
3. This issue also repro on Blazor web app for Wasm project.
4. This issue also repro on wwwroot/app.css file, does not repro on .razor file.

Error Log

[oroztocil]

@tmat Can you take a look again? It looks the issue might not be fixed as we thought after the SDK fix.

[tmat]

Were you testing with this merged? dotnet/sdk#53288

[EmilyFeng97]

Verify this issue on the latest .NET 11.0 Preview 3[11.0.100-preview.3.26174.112], it still reproduce. But the reproduce steps are slightly different:

• If I create a Blazor web application server project and run it using dotnet watch for the first time , the bug reproduces very infrequently. Even if I refresh the browser multiple times, and even if I modify the CSS file multiple times, the problem only occurs once and then doesn't reappear.

• If I stop the project and run it again using dotnet watch, this issue will repro consistently.

[tmat]

The issue doesn't reproduce if dotnet-watch from main branch is used but the project targets net10.
It does reproduce if the project targets net11. This is likely a regression in Blazor runtime caching.

@javiercn @MackinnonBuck

[jinzhao1127]

This issue still reproduces on the latest 11.0 P3[11.0.100-preview.3.26179.102] .