build-pr.yml

name: Build Changed C# Projects for PR

on:
  pull_request:
    paths-ignore:
      - '**.md'

jobs:
  build:
    strategy:
      fail-fast: false
      matrix:
        os: [windows-latest, macos-15]

    runs-on: ${{ matrix.os }}

    steps:
    - name: Checkout code
      uses: actions/checkout@v4
      with:
        fetch-depth: 2

    - name: Install .NET 9
      uses: actions/setup-dotnet@v4
      with:
        dotnet-version: 9.0

    - name: Install .NET MAUI Workload
      run: dotnet workload install maui

    - name: Select Xcode Version
      run: sudo xcode-select -s /Applications/Xcode_16.2.app
      if: runner.os == 'macOS'

    - name: Find and build changed projects
      run: |
        $failedProjectCount=0
        # Get the list of changed files
        $changedFiles = git diff --name-only -r --diff-filter=d HEAD^1 HEAD

        $excluded_projects_file="./eng/excluded_projects_" + "${{ runner.os }}".ToLower() + ".txt"
        $excluded_projects=@()
        $processedProjects=@()

        $jobSummaryFile=$env:GITHUB_STEP_SUMMARY

        if (Test-Path $excluded_projects_file) {
            $excluded_projects = Get-Content -Path $excluded_projects_file | Where-Object { $_ -notmatch "^\s*#" -and $_ -match "\S" }
        }

        Write-Output "# .NET MAUI Sample Apps Build Status (${{ runner.os }})" | Out-File -FilePath $jobSummaryFile -Append
        Write-Output "Only projects that have changes are built." | Out-File -FilePath $jobSummaryFile -Append
        Write-Output "| Project | Build Status |" | Out-File -FilePath $jobSummaryFile -Append
        Write-Output "|---|---|" | Out-File -FilePath $jobSummaryFile -Append

        # Determine the corresponding project for each changed file
        foreach ($file in $changedFiles) {
            $projectToBuild=""

            # Check if the file is a .csproj file
            if ($file -like '*.csproj') {
              $projectToBuild = $file
            } else {
              $currentFolder = (Get-Item -LiteralPath (Resolve-Path -Path "$file")).Directory

              while ($currentFolder -ne $null -and '' -ne $currentFolder) {
                $csprojFiles = Get-ChildItem -Path $currentFolder -Filter '*.csproj' -File

                if ($csprojFiles.Count -gt 0) {
                  break
                }
                $currentFolder = Split-Path -Parent $currentFolder
              }

              if ($csprojFiles.Count -gt 0) {
                $projectToBuild = $csprojFiles[0].FullName
              }
            }

            if (-not [string]::IsNullOrEmpty($projectToBuild)) {
              $projectToBuild = (Resolve-Path -Path $projectToBuild -Relative).Replace("\", "/")

              # Only proceed when this project has not been built yet
              if (-not ($processedProjects -contains $projectToBuild)) {
                Write-Output "::notice:: $projectToBuild is not in processed builds yet"

                $processedProjects += $projectToBuild
                Write-Output "::notice:: Added $projectToBuild to processed builds"

                if ($excluded_projects -contains $projectToBuild) {
                    Write-Output "::notice:: Skipping build for excluded project: $projectToBuild"
                    Write-Output "| $projectToBuild | Skipped |" | Out-File -FilePath $jobSummaryFile -Append

                    $skippedProjectCount++
                }
                else {
                  Write-Output "::group:: Building $projectToBuild"

                  dotnet build $projectToBuild

                  if ($LASTEXITCODE -gt 0) {
                    Write-Output "::error:: Build failed for $projectToBuild"
                    Write-Output "| $projectToBuild | :x: |" | Out-File -FilePath $jobSummaryFile -Append

                    $failedProjectCount++
                  }
                  else {
                    Write-Output "Build succeeded for $projectToBuild"
                    Write-Output "| $projectToBuild | :white_check_mark: |" | Out-File -FilePath $jobSummaryFile -Append
                  }

                  $proj_dir = [System.IO.Path]::GetDirectoryName($projectToBuild)
                  Write-Output "Cleaning up bin & obj in $proj_dir"

                  try {
                    Get-ChildItem -Path $proj_dir -Directory -Recurse -Include bin,obj | Remove-Item -Recurse -Force
                  } catch {
                    Write-Output "::warning:: Failed to clean up bin & obj in $proj_dir"  
                  }

                  Write-Output "::endgroup::"
                }
              }
            }
            else {
              Write-Output "::warning:: Found no csproj for file $file"
            }
          }

        if ($failedProjectCount -gt 0) {
            Write-Output "" | Out-File -FilePath $jobSummaryFile -Append
            Write-Output "# Failed builds: $failedProjectCount" | Out-File -FilePath $jobSummaryFile -Append
            Write-Output "# Skipped builds: $skippedProjectCount" | Out-File -FilePath $jobSummaryFile -Append

            exit $failedProjectCount
        }
      shell: powershell