Cannot load Analyzers programatically from MSBuildWorkspace

[shaggygi]

Version Used:
VS 2017 (15.9.4)

Scenario:

Create a new .NET command-line project.
Add latest Microsoft.Build.Locator Nuget to project.
Add latest Microsoft.CodeAnalysis and StyleCop.Analyzers Nuget to project.
Project now has 4 Analyzer references:

Microsoft.CodeAnalysis.Analyzers
Microsoft.CodeAnalysis.CSharp.Analyzers
StyleCop.Analyzers
StyleCop.Analyzers.CodeFixes

// Add the following code to the project and run it:
MSBuildLocator.RegisterDefaults();
var workspace = MSBuildWorkspace.Create();
var project = await workspace.OpenProjectAsync(projectPath);

var allLanguageAnalyzers = project.AnalyzerReferences.SelectMany(r => r.GetAnalyzersForAllLanguages());
var languageSpecificAnalyzers = project.AnalyzerReferences.SelectMany(r => r.GetAnalyzers(project.Language));

Where projectPath is the path to this project.

Expectations:

allLanguageAnalyzers is not empty
languageSpecificAnalyzers is not empty
Actual Results:

allLanguageAnalyzers is empty
languageSpecificAnalyzers is empty

This might be similar to this older issue, but not sure, so I'm pinging the following for help.

@yaakov-h
@jmarolf
@davkean
@sharwell

[jmarolf]

@shaggygi what is projectPath pointing to? Also, that is the XML for you project file.

[shaggygi]

@jmarolf sorry for not showing that. It is a path to a .csproj file. I’ve tried console and wpf projects with same result.

[jmarolf]

@shaggygi and the project pointed to in projectPath has which analyzer references?

[shaggygi]

@jmarolf The app that runs the code includes Microsoft.CodeAnalysis and StyleCop.Analyzers and the project the code is check only has StyleCop.Analyzers added.

[shaggygi]

@jmarolf I just published a sample here if this helps. https://github.com/shaggygi/TryingAnalyzerReferences

Just need to update the path of where the other project is located.

[shaggygi]

Not sure if this is related. I noticed when I do thing following emit, the only diagnostics returned are with Hidden severity that point to things like .g. files. It seems like you would also get diagnostics that come from StyleCop.Analyzers.

EmitResult emitResult = compilation.Emit(stream);

[JPCMarques]

Any updates on this?

[jasonmalinowski]

Analyzers should be loading; this was probably some sort of binding redirect issue or something else specific to that setup.

[filzrev]

Unresolved analyzers are represented as UnresolvedAnalyzerReference.
And GetAnalyzers/GetAnalyzersForAllLanguages returns empty results.

So, if it need to detect unresolved analyzers.
It need manuall handle UnresolvedAnalyzerReference.

foreach (var unresolvedAnalyzer in project.AnalyzerReferences.OfType<UnresolvedAnalyzerReference>())
{
    Console.WriteLine($"Failed to resolve analyzer:  {unresolvedAnalyzer.FullPath}");
}

[jasonmalinowski]

@filzrev I wouldn't expect unresolved analyzers to be happening unless we ended up with a file path that doesn't exist. If you're seeing that then maybe we have a new bug (and please file one!)

[filzrev]

I wouldn't expect unresolved analyzers to be happening unless we ended up with a file path that doesn't exist.

Yes, that's right, it happens when the analyzer DLL is not found.

On some use cases. analyzer silently failed to load. (dotnet/docfx#9619 and #77255)
So It need to manually handle these cases.

• [Bug] Using Roslyn Source Generators with attribute class fails docfx#9619
• https://github.com/dotnet/docfx/blob/04746a10c565dd2566c8ee064fe23026022eed01/src/Docfx.Dotnet/DotnetApiCatalog.Compile.cs#L146-L164

[jasonmalinowski]

@filzrev Ah yes, that's another good case to capture in #77980.