contributing.md

Creating analyzer

Create analyzer project

All analyzer projects must target netstandard2.0 due to Visual Studio not loading other runtimes in code designing stage.\n You should specify <LangVersion>11</LangVersion> to use latest language features

Add NuGet build properties

Add properties for package generation

<PropertyGroup>
    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
    <IncludeBuildOutput>false</IncludeBuildOutput>
</PropertyGroup>

Add separate property group for constant NuGet package properties

<PropertyGroup>
    <PackageId>SourceKit.Analyzers.MustBePartial</PackageId>
    <Title>SourceKit.Analyzers.MustBePartial</Title>
    <Authors>ronimizy</Authors>
</PropertyGroup>

And separate group for more volatile properties

<PropertyGroup>
    <PackageReleaseNotes>Analyzers for checking whether type is partial</PackageReleaseNotes>
</PropertyGroup>

Add Roslyn SDK dependencies

<ItemGroup>
    <PackageReference Include="Microsoft.CodeAnalysis.Common"/>
    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" VersionOverride="4.5.0"/>
    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common"/>
</ItemGroup>

You have to manually add assemblies to your analyzers NuGet package path

<ItemGroup>
    <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false"/>
    <None Include="$(OutputPath)\$(AssemblyName).Annotations.dll" Pack="true" PackagePath="analyzers/dotnet/cs"
          Visible="false"/>
    <None Include="$(OutputPath)\SourceKit.dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false"/>
</ItemGroup>

Docs

Implementation

Choose diagnostic category, based on MS Docs listing
https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/categories

Writing sample code

After implementing your analyzer code, include sample code, describing all use cases of your feature into SourceKit.Sample project

Use designated folder for it (ex: Analyzers/MustBePartial)

Unit testing

You should validate your sample code using unit tests.

Analyzers

1. Specify type alias for your verifier

   using Verify = Microsoft.CodeAnalysis.CSharp.Testing.XUnit.AnalyzerVerifier<{AnalyzerType}>;

2. Create CSharpAnalyzerTest<{AnalyzerType}, XUnitVerifier> instance
3. Add source files using SourceFile.LoadAsync

   var test = new CSharpAnalyzerTest<{AnalyzerType}, XUnitVerifier>
   {
      TestState =
      {
          Sources =
          {
              await SourceFile.LoadAsync("..."),
          },
      },
   };

4. Add reference to annotations package

   var test = new CSharpAnalyzerTest<{AnalyzerType}, XUnitVerifier>
   {
      TestState =
      {
          AdditionalReferences = { typeof(SomeAttribute).Assembly },
      },
   };

5. Specify diagnostics if they are expected

   var diagnostic = Verify.Diagnostic(Analyzer.Descriptor)
      .WithLocation(sourceFile.Name, 3, 14)
      .WithArguments(nameof(SomeType));
   
   var test = new CSharpAnalyzerTest<{AnalyzerType}, XUnitVerifier>
   {
      ExpectedDiagnostics = { diagnostic },
   };

6. Run test

   await test.RunAsync();

CodeFix providers

1. Specify type alias for your verifier

   using Verify = Microsoft.CodeAnalysis.CSharp.Testing.XUnit.AnalyzerVerifier<{AnalyzerType}>;

2. Specify type alias for your code fix test

   using CodeFixTest = Microsoft.CodeAnalysis.CSharp.Testing.CSharpCodeFixTest<
       {AnalyzerType},
       {CodeFixProviderType},
       Microsoft.CodeAnalysis.Testing.Verifiers.XUnitVerifier>;

3. Add source files using SourceFile.LoadAsync

   var test = new CodeFixTest
   {
      TestState =
      {
          Sources =
          {
              await SourceFile.LoadAsync("..."),
          },
      },
   };

4. Add reference to annotations package

   var test = new CodeFixTest
   {
      TestState =
      {
          AdditionalReferences = { typeof(SomeAttribute).Assembly },
      },
   };

5. Specify diagnostics if they are expected

   var diagnostic = Verify.Diagnostic(Analyzer.Descriptor)
      .WithLocation(sourceFile.Name, 3, 14)
      .WithArguments(nameof(SomeType));
   
   var test = new CodeFixTest
   {
      ExpectedDiagnostics = { diagnostic },
   };

6. Specify fixed state

   var test = new CodeFixTest
   {
      FixedState =
      {
          Sources = { fixedSource, interfaceSource },
      },
   };

7. Run test

   await test.RunAsync();