Switch to coverlet.collector for code coverage

.gitignore

@@ -11,6 +11,9 @@ packages/
 TestResults/
 OpenCover.Reports/
 OpenCover.Symbols/
+.coverage/
+coverage/
+coverage-*/
 .nuget/NuGet.exe
 build/nuget/
 *.log

.nuget/packages.config

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="CodecovUploader" version="0.7.1" />
-  <package id="OpenCover" version="4.6.519" />
   <package id="ReportGenerator" version="5.2.0" />
   <package id="xunit.runner.console" version="2.4.1" />
-</packages>
+</packages>

CONTRIBUTING.md

@@ -13,6 +13,41 @@ You can also help by filing issues, participating in discussions and doing code
 * The version of the [.NET Core SDK](https://dotnet.microsoft.com/download/dotnet-core) as specified in the global.json file at the root of this repo.
   Use the init script at the root of the repo to conveniently acquire and install the right version.
 
+## Code coverage
+
+You can generate local coverage using the built-in scripts after running `init.ps1` and a build.
+
+- Full coverage (Release):
+
+  ```powershell
+  .\build\coverage-report.ps1
+  ```
+
+- Full coverage (Debug):
+
+  ```powershell
+  .\build\coverage-report.ps1 -Debug
+  ```
+
+- Diff-focused coverage (changed files vs origin/master):
+
+  ```powershell
+  .\build\coverage-report.ps1 -DiffOnly
+  ```
+
+- Diff-focused coverage against a specific base:
+
+  ```powershell
+  .\build\coverage-report.ps1 -DiffBase origin/main -DiffOnly
+  ```
+
+Outputs:
+- Cobertura XML: `build\coverage\OpenCover.StyleCopAnalyzers.CSharp*.xml`
+- HTML report: `build\coverage\index.htm`
+- Diff HTML (when requested): `build\coverage\diff\index.htm`
+
+CI uses `dotnet test` with `coverlet.collector` and merges Cobertura reports with ReportGenerator before uploading to Codecov. The same filters are applied locally and in CI to keep results consistent. Test failures or missing coverage files will cause the coverage script to fail with a non-zero exit code.
+
 ## Implementing a diagnostic
 
 1. To start working on a diagnostic, add a comment to the issue indicating you are working on implementing it.

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/StyleCop.Analyzers.Test.CSharp10.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.1" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -34,4 +36,4 @@
     <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp11/StyleCop.Analyzers.Test.CSharp11.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.4.0" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -35,4 +37,4 @@
     <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp12/StyleCop.Analyzers.Test.CSharp12.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.8.0" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -36,4 +38,4 @@
     <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp13/StyleCop.Analyzers.Test.CSharp13.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.12.0" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -37,4 +39,4 @@
     <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp7/StyleCop.Analyzers.Test.CSharp7.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="2.8.2" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -37,4 +39,4 @@
     </None>
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp8/StyleCop.Analyzers.Test.CSharp8.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.6.0" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -35,4 +37,4 @@
     <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp9/StyleCop.Analyzers.Test.CSharp9.csproj

@@ -19,6 +19,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.8.0" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -33,4 +35,4 @@
     <ProjectReference Include="..\StyleCop.Analyzers.PrivateCodeFixes\StyleCop.Analyzers.PrivateCodeFixes.csproj" PrivateAssets="all" SetTargetFramework="TargetFramework=netstandard2.0" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>
 
-</Project>
+</Project>

StyleCop.Analyzers/StyleCop.Analyzers.Test/StyleCop.Analyzers.Test.csproj

@@ -22,6 +22,7 @@
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="1.3.2" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.CodeFix.Testing.XUnit" Version="1.1.2-beta1.23509.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.13.0" />
+    <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="Xunit.Combinatorial" Version="1.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" PrivateAssets="all" />
@@ -54,4 +55,4 @@
     </None>
   </ItemGroup>
 
-</Project>
+</Project>

build/build-and-test.yml

@@ -281,7 +281,7 @@ stages:
           $packages_folder = '.\packages'
           $reportgenerator_version = $packageConfig.SelectSingleNode('/packages/package[@id="ReportGenerator"]').version
           $report_generator = "$packages_folder\ReportGenerator.$reportgenerator_version\tools\net47\ReportGenerator.exe"
-          &$report_generator -targetdir:$(Pipeline.Workspace)/coverageResults-final -reporttypes:Cobertura "-reports:$(Pipeline.Workspace)/coverageResults-*/OpenCover.*.xml"
+          &$report_generator -targetdir:$(Pipeline.Workspace)/coverageResults-final -reporttypes:Cobertura "-reports:$(Pipeline.Workspace)/coverageResults-*/coverage/OpenCover.*.xml"
 
     - task: PowerShell@2
       displayName: Public code coverage to codecov.io

build/coverage-report.ps1

@@ -0,0 +1,122 @@
+param (
+    [switch]$Debug,
+    [switch]$NoBuild,
+    [switch]$NoReport,
+    [switch]$AppVeyor,
+    [switch]$Azure,
+    [string]$DiffBase,
+    [switch]$DiffOnly
+)
+
+$ErrorActionPreference = 'Stop'
+
+$scriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+Push-Location $scriptDir
+
+try {
+    if (-not $NoBuild) {
+        if ($Debug) {
+            .\build.ps1 -Debug -Incremental
+        } else {
+            .\build.ps1 -Incremental
+        }
+    }
+
+    $configuration = if ($Debug) { 'Debug' } else { 'Release' }
+    $resultsRoot = Join-Path $scriptDir 'TestResults'
+    $coverageRoot = Join-Path $scriptDir 'coverage'
+
+    if (Test-Path $resultsRoot) {
+        Remove-Item -Recurse -Force $resultsRoot
+    }
+
+    if (Test-Path $coverageRoot) {
+        Remove-Item -Recurse -Force $coverageRoot
+    }
+
+    New-Item -ItemType Directory -Force -Path $resultsRoot | Out-Null
+    New-Item -ItemType Directory -Force -Path $coverageRoot | Out-Null
+
+    $runs = @(
+        @{ Lang = '6'; Project = 'StyleCop.Analyzers.Test'; Framework = 'net452' }
+        @{ Lang = '7'; Project = 'StyleCop.Analyzers.Test.CSharp7'; Framework = 'net46' }
+        @{ Lang = '8'; Project = 'StyleCop.Analyzers.Test.CSharp8'; Framework = 'net472' }
+        @{ Lang = '9'; Project = 'StyleCop.Analyzers.Test.CSharp9'; Framework = 'net472' }
+        @{ Lang = '10'; Project = 'StyleCop.Analyzers.Test.CSharp10'; Framework = 'net472' }
+        @{ Lang = '11'; Project = 'StyleCop.Analyzers.Test.CSharp11'; Framework = 'net472' }
+        @{ Lang = '12'; Project = 'StyleCop.Analyzers.Test.CSharp12'; Framework = 'net472' }
+        @{ Lang = '13'; Project = 'StyleCop.Analyzers.Test.CSharp13'; Framework = 'net472' }
+    )
+
+    foreach ($run in $runs) {
+        $projectPath = Join-Path $scriptDir "..\StyleCop.Analyzers\$($run.Project)\$($run.Project).csproj"
+        $runResultsDir = Join-Path $resultsRoot "CSharp$($run.Lang)"
+        New-Item -ItemType Directory -Force -Path $runResultsDir | Out-Null
+
+        $trxName = "StyleCopAnalyzers.CSharp$($run.Lang).trx"
+
+        dotnet test $projectPath `
+            --framework $run.Framework `
+            --configuration $configuration `
+            --no-build `
+            --settings (Join-Path $scriptDir 'coverlet.runsettings') `
+            --results-directory $runResultsDir `
+            --logger "trx;LogFileName=$trxName" `
+            --collect:"XPlat Code Coverage"
+
+        $coverageFile = Get-ChildItem -Path $runResultsDir -Recurse -Filter 'coverage.cobertura.xml' -ErrorAction SilentlyContinue | Select-Object -First 1
+        if (-not $coverageFile) {
+            throw "Coverage file not found for C# $($run.Lang) in $runResultsDir"
+        }
+
+        Copy-Item $coverageFile.FullName (Join-Path $coverageRoot "OpenCover.StyleCopAnalyzers.CSharp$($run.Lang).xml") -Force
+    }
+
+    if (-not $NoReport) {
+        $packageConfig = [xml](Get-Content ..\.nuget\packages.config)
+        $packagesFolder = '..\packages'
+        $reportGeneratorVersion = $packageConfig.SelectSingleNode('/packages/package[@id="ReportGenerator"]').version
+        $reportGenerator = "$packagesFolder\ReportGenerator.$reportGeneratorVersion\tools\ReportGenerator.exe"
+
+        &$reportGenerator -targetdir:$coverageRoot -reporttypes:Html;Cobertura "-reports:$coverageRoot\OpenCover.*.xml"
+        Write-Host "Open $coverageRoot\index.htm to see code coverage results."
+
+        $shouldGenerateDiff = $DiffOnly -or -not [string]::IsNullOrWhiteSpace($DiffBase)
+        if ($shouldGenerateDiff) {
+            $baseRef = if ([string]::IsNullOrWhiteSpace($DiffBase)) { 'origin/master' } else { $DiffBase }
+            $repoRoot = Resolve-Path (Join-Path $scriptDir '..')
+
+            try {
+                $diffFiles = & git -C $repoRoot diff --name-only --diff-filter=AM "$baseRef...HEAD" 2>$null | Where-Object { $_ -like '*.cs' }
+                if (-not $diffFiles) {
+                    Write-Warning "No changed .cs files found relative to '$baseRef'; skipping diff coverage output."
+                }
+                else {
+                    $diffFilters = $diffFiles | ForEach-Object {
+                        $normalized = ($_ -replace '\\', '/')
+                        "+**/$normalized"
+                    }
+
+                    $diffTarget = Join-Path $coverageRoot 'diff'
+                    New-Item -ItemType Directory -Force -Path $diffTarget | Out-Null
+
+                    &$reportGenerator -targetdir:$diffTarget -reporttypes:Html;TextSummary "-reports:$coverageRoot\OpenCover.*.xml" "-filefilters:$($diffFilters -join ';')"
+
+                    $summaryPath = Get-ChildItem $diffTarget -Filter '*Summary.txt' -ErrorAction SilentlyContinue | Select-Object -First 1
+                    if ($summaryPath) {
+                        Write-Host "Diff coverage summary (relative to $baseRef):"
+                        Get-Content $summaryPath.FullName
+                    }
+
+                    Write-Host "Diff coverage HTML: $diffTarget\index.htm"
+                }
+            }
+            catch {
+                Write-Warning "Failed to compute diff coverage relative to '$baseRef': $($_.Exception.Message)"
+            }
+        }
+    }
+}
+finally {
+    Pop-Location
+}

build/coverlet.runsettings

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RunSettings>
+  <DataCollectionRunSettings>
+    <DataCollectors>
+      <DataCollector friendlyName="XPlat Code Coverage">
+        <Configuration>
+          <Format>cobertura</Format>
+          <IncludeTestAssembly>true</IncludeTestAssembly>
+          <SingleHit>true</SingleHit>
+          <Include>[StyleCop*]*</Include>
+          <ExcludeByAttribute>System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute</ExcludeByAttribute>
+          <ExcludeByFile>**/*Designer.cs</ExcludeByFile>
+        </Configuration>
+      </DataCollector>
+    </DataCollectors>
+  </DataCollectionRunSettings>
+</RunSettings>