Blazor WASM: BrowserDebugHost.dll running from DevServer is missing roll-forward runtime policy

[seclerp]

Description

When the default standalone Blazor WebAssembly project is starting, it's hosted using DevServer. Then, DevServer starts framework-dependent BrowserDebugHost.dll when it receives /debug/ws-proxy?... request. But, unlike DevServer itself, BrowserDebugHost.dll is missing configuration to roll forward on available runtime versions. This leads to situations when the user is able to start the application itself using dotnet run, but DevServer runs BrowserDebugHost using dotnet exec, which requires a specific runtime version by default.

Reproduction Steps

1. Uninstall .NET 6 SDK (if installed)
2. Install .NET 7 SDK or .NET 8 SDK
3. dotnet new blazorwasm -n TestApp1
4. Open the newly created project in VS Code
5. Change TFM from net7.0 to net6.0
6. Change NuGet versions from 7.0.8 to 6.0.19
7. dotnet build
8. Run the project with debugging enabled ("Launch and Debug Standalone WebAssembly App")

A preconfigured project can be found here.

Expected behavior

The app is running correctly, debugging is completely working as usual.

Actual behavior

The app starts, but debugging is completely broken, with a lot of exceptions in the console.

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
      An unhandled exception has occurred while executing the request.
      System.InvalidOperationException: No output has been recevied from the application.
         at Microsoft.AspNetCore.Builder.DebugProxyLauncher.LaunchAndGetUrl(IServiceProvider serviceProvider, String devToolsHost)
         at Microsoft.AspNetCore.Builder.WebAssemblyNetDebugProxyAppBuilderExtensions.<>c.<<UseWebAssemblyDebugging>b__0_1>d.MoveNext()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.InvokeCore(HttpContext context, PathString matchedPath, PathString remainingPath)
         at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

Regression?

No response

Known Workarounds

Since we can't control the process creation process for BrowserDebugHost.dll in DevServer, the only available option is to set the environment variable for DevServer and let it propagate to a child process with BrowserDebugHost.dll.

So DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX =2 or DOTNET_ROLL_FORWARD=Major should be used.

Options are from here.

Configuration

.NET SDK:
 Version:   8.0.100-preview.5.23303.2
 Commit:    3fe444af72

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  13.4
 OS Platform: Darwin
 RID:         osx.13-arm64
 Base Path:   /usr/local/share/dotnet/sdk/8.0.100-preview.5.23303.2/

.NET workloads installed:
 [maui]
   Installation Source: SDK 8.0.100-preview.5
   Manifest Version:    8.0.0-preview.5.8529/8.0.100-preview.5
   Manifest Path:       /usr/local/share/dotnet/sdk-manifests/8.0.100-preview.5/microsoft.net.sdk.maui/WorkloadManifest.json
   Install Type:        FileBased
 [wasm-tools-net7]
   Installation Source: SDK 8.0.100-preview.5
   Manifest Version:    8.0.0-preview.5.23280.8/8.0.100-preview.5
   Manifest Path:       /usr/local/share/dotnet/sdk-manifests/8.0.100-preview.5/microsoft.net.workload.mono.toolchain.net7/WorkloadManifest.json
   Install Type:        FileBased

Host:
  Version:      8.0.0-preview.5.23280.8
  Architecture: arm64
  Commit:       bc78804f5d

.NET SDKs installed:
  7.0.203 [/usr/local/share/dotnet/sdk]
  8.0.100-preview.4.23260.5 [/usr/local/share/dotnet/sdk]
  8.0.100-preview.5.23303.2 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.4.23260.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.5.23302.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.4.23259.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.5.23280.8 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  x64   [/usr/local/share/dotnet/x64]
    registered at [/etc/dotnet/install_location_x64]

Other information

A possible fix for such an issue is to add runtimeconfig.template.json for the BrowserDebugHost project itself, with a pre-configured roll-forward policy:

{
  "tfm": "net7.0",
  "rollForward": "Major"
}

Or using a project file:

<PropertyGroup>
  <RollForward>Major</RollForward>
</PropertyGroup>

Tagging subscribers to this area: @vitek-karas, @agocke, @VSadov
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

When the default standalone Blazor WebAssembly project is starting, it's hosted using DevServer. Then, DevServer starts framework-dependent BrowserDebugHost.dll when it receives /debug/ws-proxy?... request. But, unlike DevServer itself, BrowserDebugHost.dll is missing configuration to roll forward on available runtime versions. This leads to situations when the user is able to start the application itself using dotnet run, but DevServer runs BrowserDebugHost using dotnet exec, which requires a specific runtime version by default.

Reproduction Steps

1. Uninstall .NET 6 SDK (if installed)
2. Install .NET 7 SDK or .NET 8 SDK
3. dotnet new blazorwasm -n TestApp1
4. Open the newly created project in VS Code
5. Change TFM from net7.0 to net6.0
6. Change NuGet versions from 7.0.8 to 6.0.19
7. dotnet build
8. Run the project with debugging enabled ("Launch and Debug Standalone WebAssembly App")

A preconfigured project can be found here.

Expected behavior

The app is running correctly, debugging is completely working as usual.

Actual behavior

The app starts, but debugging is completely broken, with a lot of exceptions in the console.

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
      An unhandled exception has occurred while executing the request.
      System.InvalidOperationException: No output has been recevied from the application.
         at Microsoft.AspNetCore.Builder.DebugProxyLauncher.LaunchAndGetUrl(IServiceProvider serviceProvider, String devToolsHost)
         at Microsoft.AspNetCore.Builder.WebAssemblyNetDebugProxyAppBuilderExtensions.<>c.<<UseWebAssemblyDebugging>b__0_1>d.MoveNext()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.InvokeCore(HttpContext context, PathString matchedPath, PathString remainingPath)
         at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

Regression?

No response

Known Workarounds

Since we can't control the process creation process for BrowserDebugHost.dll in DevServer, the only available option is to set the environment variable for DevServer and let it propagate to a child process with BrowserDebugHost.dll.

So DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX =2 or DOTNET_ROLL_FORWARD=Major should be used.

Options are from here.

Configuration

.NET SDK:
 Version:   8.0.100-preview.5.23303.2
 Commit:    3fe444af72

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  13.4
 OS Platform: Darwin
 RID:         osx.13-arm64
 Base Path:   /usr/local/share/dotnet/sdk/8.0.100-preview.5.23303.2/

.NET workloads installed:
 [maui]
   Installation Source: SDK 8.0.100-preview.5
   Manifest Version:    8.0.0-preview.5.8529/8.0.100-preview.5
   Manifest Path:       /usr/local/share/dotnet/sdk-manifests/8.0.100-preview.5/microsoft.net.sdk.maui/WorkloadManifest.json
   Install Type:        FileBased
 [wasm-tools-net7]
   Installation Source: SDK 8.0.100-preview.5
   Manifest Version:    8.0.0-preview.5.23280.8/8.0.100-preview.5
   Manifest Path:       /usr/local/share/dotnet/sdk-manifests/8.0.100-preview.5/microsoft.net.workload.mono.toolchain.net7/WorkloadManifest.json
   Install Type:        FileBased

Host:
  Version:      8.0.0-preview.5.23280.8
  Architecture: arm64
  Commit:       bc78804f5d

.NET SDKs installed:
  7.0.203 [/usr/local/share/dotnet/sdk]
  8.0.100-preview.4.23260.5 [/usr/local/share/dotnet/sdk]
  8.0.100-preview.5.23303.2 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.4.23260.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.5.23302.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.4.23259.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.5.23280.8 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  x64   [/usr/local/share/dotnet/x64]
    registered at [/etc/dotnet/install_location_x64]

Other information

A possible fix for such an issue is to add runtimeconfig.template.json for the BrowserDebugHost project itself, with a pre-configured roll-forward policy:

{
  "tfm": "net7.0",
  "rollForward": "Major"
}

Or using a project file:

<PropertyGroup>
  <RollForward>Major</RollForward>
</PropertyGroup>

Author:	seclerp
Assignees:	-
Labels:	area-Host
Milestone:	-

Tagging subscribers to 'arch-wasm': @lewing
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

When the default standalone Blazor WebAssembly project is starting, it's hosted using DevServer. Then, DevServer starts framework-dependent BrowserDebugHost.dll when it receives /debug/ws-proxy?... request. But, unlike DevServer itself, BrowserDebugHost.dll is missing configuration to roll forward on available runtime versions. This leads to situations when the user is able to start the application itself using dotnet run, but DevServer runs BrowserDebugHost using dotnet exec, which requires a specific runtime version by default.

Reproduction Steps

1. Uninstall .NET 6 SDK (if installed)
2. Install .NET 7 SDK or .NET 8 SDK
3. dotnet new blazorwasm -n TestApp1
4. Open the newly created project in VS Code
5. Change TFM from net7.0 to net6.0
6. Change NuGet versions from 7.0.8 to 6.0.19
7. dotnet build
8. Run the project with debugging enabled ("Launch and Debug Standalone WebAssembly App")

A preconfigured project can be found here.

Expected behavior

The app is running correctly, debugging is completely working as usual.

Actual behavior

The app starts, but debugging is completely broken, with a lot of exceptions in the console.

fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
      An unhandled exception has occurred while executing the request.
      System.InvalidOperationException: No output has been recevied from the application.
         at Microsoft.AspNetCore.Builder.DebugProxyLauncher.LaunchAndGetUrl(IServiceProvider serviceProvider, String devToolsHost)
         at Microsoft.AspNetCore.Builder.WebAssemblyNetDebugProxyAppBuilderExtensions.<>c.<<UseWebAssemblyDebugging>b__0_1>d.MoveNext()
      --- End of stack trace from previous location ---
         at Microsoft.AspNetCore.Builder.Extensions.MapMiddleware.InvokeCore(HttpContext context, PathString matchedPath, PathString remainingPath)
         at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddlewareImpl.Invoke(HttpContext context)

Regression?

No response

Known Workarounds

Since we can't control the process creation process for BrowserDebugHost.dll in DevServer, the only available option is to set the environment variable for DevServer and let it propagate to a child process with BrowserDebugHost.dll.

So DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX =2 or DOTNET_ROLL_FORWARD=Major should be used.

Options are from here.

Configuration

.NET SDK:
 Version:   8.0.100-preview.5.23303.2
 Commit:    3fe444af72

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  13.4
 OS Platform: Darwin
 RID:         osx.13-arm64
 Base Path:   /usr/local/share/dotnet/sdk/8.0.100-preview.5.23303.2/

.NET workloads installed:
 [maui]
   Installation Source: SDK 8.0.100-preview.5
   Manifest Version:    8.0.0-preview.5.8529/8.0.100-preview.5
   Manifest Path:       /usr/local/share/dotnet/sdk-manifests/8.0.100-preview.5/microsoft.net.sdk.maui/WorkloadManifest.json
   Install Type:        FileBased
 [wasm-tools-net7]
   Installation Source: SDK 8.0.100-preview.5
   Manifest Version:    8.0.0-preview.5.23280.8/8.0.100-preview.5
   Manifest Path:       /usr/local/share/dotnet/sdk-manifests/8.0.100-preview.5/microsoft.net.workload.mono.toolchain.net7/WorkloadManifest.json
   Install Type:        FileBased

Host:
  Version:      8.0.0-preview.5.23280.8
  Architecture: arm64
  Commit:       bc78804f5d

.NET SDKs installed:
  7.0.203 [/usr/local/share/dotnet/sdk]
  8.0.100-preview.4.23260.5 [/usr/local/share/dotnet/sdk]
  8.0.100-preview.5.23303.2 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.4.23260.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.0-preview.5.23302.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 7.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.4.23259.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.0-preview.5.23280.8 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  x64   [/usr/local/share/dotnet/x64]
    registered at [/etc/dotnet/install_location_x64]

Other information

A possible fix for such an issue is to add runtimeconfig.template.json for the BrowserDebugHost project itself, with a pre-configured roll-forward policy:

{
  "tfm": "net7.0",
  "rollForward": "Major"
}

Or using a project file:

<PropertyGroup>
  <RollForward>Major</RollForward>
</PropertyGroup>

Author:	seclerp
Assignees:	-
Labels:	arch-wasm, area-Host, untriaged
Milestone:	-

[radical]

cc @ilonatommy @thaystg