[Bug] Metadata extraction fails with .NET SDK 10.0.2xx — Razor compiler requires Roslyn 5.3.0

[uo-uhbc]

DocFx Version

2.78.5

.NET SDK Versions Tested

SDK Version	Result
10.0.103 (100-band)	Works
10.0.201 (200-band)	Fails

Describe the Bug

docfx metadata fails for projects containing Blazor components when running with .NET SDK 10.0.2xx (200-band). The issue does not occur with SDK 10.0.1xx (100-band).

Root Cause

The Razor compiler analyzer shipped with the 200-band SDK requires Roslyn 5.3.0, but DocFx bundles an older version that cannot load it:

warning: FailedToLoadAnalyzer: Failed to load .NET Analyzer.
  AnalyzerName: Microsoft.CodeAnalysis.Razor.Compiler
  ErrorCode: ReferencesNewerCompiler
  ReferencedCompilerVersion: 5.3.0.0

Because the Razor source generator fails to load, it does not produce the generated partial classes for .razor files. Code-behind files (.razor.cs) that override virtual methods from their base class then fail with CS0115 ("no suitable method found to override"), because the generated partial class — which establishes the inheritance chain via @inherits — is missing.

Affected Components

The failure affects Blazor components that:

1. Declare their base class via @inherits in the .razor file (standard Blazor pattern)
2. Override virtual or abstract methods from that base class in the .razor.cs code-behind

Common overridden methods that trigger CS0115 include OnInitialized(), OnInitializedAsync(), SetParametersAsync(ParameterView), and custom virtual methods from the component's base class hierarchy.

To Reproduce

1. Install .NET SDK 10.0.2xx (e.g., 10.0.201)
2. Have a Blazor component library targeting net10.0
3. Include components with code-behind files where the .razor file uses @inherits SomeBase and the .razor.cs file overrides virtual methods from that base
4. Run docfx metadata on a DocFx config that includes this project

Example Component Structure

MyComponent.razor:

@namespace MyApp.Components
@inherits MyComponentBase

<div>@ChildContent</div>

MyComponent.razor.cs:

namespace MyApp.Components;

public partial class MyComponent
{
    protected override void OnInitialized()
    {
        // CS0115 because Razor generator didn't run,
        // so this partial class has no base class
        base.OnInitialized();
    }
}

Error Output

warning: FailedToLoadAnalyzer: Failed to load .NET Analyzer.
  AnalyzerName: Microsoft.CodeAnalysis.Razor.Compiler
  ErrorCode: ReferencesNewerCompiler
  ReferencedCompilerVersion: 5.3.0.0

error CS0115: 'MyComponent.OnInitialized()': no suitable method found to override

Workaround

Pin the .NET SDK to the 100-band (e.g., 10.0.103) via global.json or CI configuration. The 100-band SDK ships with a Roslyn version that DocFx can still load.

Expected Behavior

docfx metadata should work with all current .NET SDK 10 versions, including the 200-band. DocFx should be updated to support the Roslyn version shipped with the 200-band SDK.

Related Issues

• [Bug] CS8256 triggered for CSPROJ targetting .NET 10 #10901 — CS8652 triggered for .NET 10 (DocFx's Roslyn doesn't support C# 14 field keyword)
• [Bug] Metadata extraction fails when C# projects pull in a newer compiler than DocFX ships with #10192 — Metadata extraction fails when projects use a newer compiler than DocFx ships with
• Runtime analyzers now reference Roslyn 4.14.0.0 and fail to load in some hosts runtime#120815 — Runtime analyzers target Roslyn 4.14.0 but DocFx bundles 4.12.0

[uo-uhbc]

Minimal reproduction repo: https://github.com/uo-uhbc/docfx_11046