Azure Pipeline生成.NET Core代码覆盖率报告失败，求原因及解决方法

尝试使用Azure Pipeline为.NET Core项目生成代码覆盖率结果，pipeline.yml配置如下：

trigger:
- sonar-analysis

pool:
  vmImage: 'ubuntu-latest'

variables:
  solution: '**/*.sln'
  buildPlatform: 'Any CPU'
  buildConfiguration: 'Release'

steps:

- checkout: self
  persistCredentials: true
  submodules: true

- task: UseDotNet@2
  inputs:
    version: '6.x'
- task: DotNetCoreCLI@2
  inputs:
    command: 'build'
    projects: '**/**/*.csproj'
    arguments: '--verbosity n'

- task: DotNetCoreCLI@2
  displayName: 'dotnet test'
  inputs:
    command: 'test'
    projects: '**/*Tests/*.csproj'
    arguments: '--configuration $(buildConfiguration) --collect:"XPlat Code Coverage" -- DataCollectionRunSettings.DataCollectors.DataCollector.Configuration.Format=cobertura'
  
- task: PublishCodeCoverageResults@1
  displayName: 'Publish code coverage report'
  inputs:
    codeCoverageTool: 'Cobertura'
    summaryFileLocation: '$(Agent.TempDirectory)/**/coverage.cobertura.xml'

测试可成功运行并在Tests标签页显示结果，但无法生成代码覆盖率报告，相关错误如下：

dotnet test任务错误：

Data collector 'XPlat code coverage' message:
[coverlet]System.TypeLoadException: Could not load type
'Microsoft.Extensions.DependencyInjection.ServiceCollection' from
assembly 'Microsoft.Extensions.DependencyInjection, Version=6.0.0.0,
Culture=neutral, PublicKeyToken=xyz'. at
Coverlet.Collector.DataCollection.CoverletCoverageCollector.GetDefaultServiceCollection(TestPlatformEqtTrace
eqtTrace, TestPlatformLogger logger, String testModule) at
Coverlet.Collector.DataCollection.CoverletCoverageCollector.OnSessionStart(Object
sender, SessionStartEventArgs sessionStartEventArgs) in
/_/src/coverlet.collector/DataCollection/CoverletCoverageCollector.cs:line
132.

Publish Code Coverage Results任务警告：

##[warning]No code coverage results were found to publish.

相同流水线在其他项目可正常运行，请问该问题的原因及解决方法是什么？

该错误由coverlet.collector与项目依赖的Microsoft.Extensions.DependencyInjection组件版本不匹配导致。当coverlet尝试加载.NET 6版本的ServiceCollection类型时，项目中可能引用了该组件的其他版本（如更低版本），或测试项目依赖项存在版本冲突，导致类型加载失败，进而无法生成覆盖率报告文件。

• 更新coverlet.collector版本：在测试项目的.csproj文件中，明确指定与.NET 6兼容的稳定版本，替换原有引用：

  <PackageReference Include="coverlet.collector" Version="3.2.0">
    <PrivateAssets>all</PrivateAssets>
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
  </PackageReference>
  

• 统一依赖版本：确保项目中所有Microsoft.Extensions.DependencyInjection相关依赖的版本与.NET 6（6.0.x）保持一致，避免冲突。可在解决方案的Directory.Packages.props文件中统一管理版本：

  <Project>
    <PropertyGroup>
      <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
    </PropertyGroup>
    <ItemGroup>
      <PackageVersion Include="Microsoft.Extensions.DependencyInjection" Version="6.0.1" />
    </ItemGroup>
  </Project>
  

• 清理并重新构建：在流水线的build步骤前添加清理命令，清除残留的旧版本依赖文件：

  - task: DotNetCoreCLI@2
    inputs:
      command: 'clean'
      projects: '**/**/*.csproj'
      arguments: '--configuration $(buildConfiguration)'
  

• 改用coverlet.msbuild方式：若collector方式仍有问题，可切换为msbuild集成方式，直接在测试命令中指定覆盖率参数：

  - task: DotNetCoreCLI@2
    displayName: 'dotnet test with coverage'
    inputs:
      command: 'test'
      projects: '**/*Tests/*.csproj'
      arguments: '--configuration $(buildConfiguration) /p:CollectCoverage=true /p:CoverletOutputFormat=cobertura /p:CoverletOutput=$(Agent.TempDirectory)/coverage.cobertura.xml'
  

  同时确保测试项目引用coverlet.msbuild包：

  <PackageReference Include="coverlet.msbuild" Version="3.2.0">
    <PrivateAssets>all</PrivateAssets>
    <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
  </PackageReference>
  

内容的提问来源于stack exchange，提问作者Ajinkya Bapat