stage-determine-changes.yml

jobs:
- job: evaluate_changes
  displayName: 'Check for Doc Only Changes'
  pool:
    vmImage: 'ubuntu-latest'
  steps:
  - powershell: |
      # Determine the context of the build (PR or push) and set the target branch accordingly
      $isPR = "$(Build.Reason)" -eq "PullRequest"

      # Normalize the target branch name for PR builds or default to 'master' for push builds
      $targetBranchName = $isPR ? "$(System.PullRequest.TargetBranch)" -replace 'refs/heads/', '' : "master"
      Write-Host "Build context determined: $(if ($isPR) { 'Pull Request targeting ' + $targetBranchName } else { 'Push' })"

      # Fetch the target or default base branch and determine the merge base
      git fetch origin $targetBranchName
      $mergeBase = git merge-base HEAD "origin/$targetBranchName"
      Write-Host "Merge base with '$targetBranchName' identified at $mergeBase"

      Write-Host "Comparing changes from $mergeBase..."
      $gitDiffCommand = "git diff $mergeBase --name-only"
      $changedFiles = Invoke-Expression $gitDiffCommand
      $docsOnly = $false
      $nonDocsOnly = $false
      $mixedChanges = $false
      $docFiles = 0
      $nonDocFiles = 0

      if ($changedFiles) {
          Write-Host "Changed files:"
          Write-Host $changedFiles
      } else {
          Write-Host "No files have changed."
      }

      foreach ($file in $changedFiles -split "`n") {
          # Identifying changes as documentation if they occur:
          # Within any 'doc' folder in the repo (at any level), or
          # Are Markdown files at the root level or within subdirectories
          $isDoc = $file -match "/doc/" -or   # Path contains '/doc/' indicating it's within a doc folder at any level
                  $file -match "^doc/" -or    # Path starts with 'doc/' indicating it's in a root-level doc folder
                  $file -match "\.md$"        # File ends with .md indicating it's a Markdown file

          if ($isDoc) {
              $docFiles++
          } else {
              $nonDocFiles++
          }
      }

      Write-Host "Documentation files changed: $docFiles"
      Write-Host "Non-documentation files changed: $nonDocFiles"

      if ($docFiles -gt 0 -and $nonDocFiles -eq 0) {
          $docsOnly = $true
          Write-Host "All changes are documentation-only."
      } elseif ($docFiles -gt 0 -and $nonDocFiles -gt 0) {
          $mixedChanges = $true
          Write-Host "Mixed changes detected: Both documentation and non-documentation files have been modified."
      } elseif ($nonDocFiles -gt 0) {
          $nonDocsOnly = $true
          Write-Host "Non-documentation changes detected."
      }

      # Explicitly write the final values for clarity
      Write-Host "Final values:"
      Write-Host "docsOnly: $docsOnly"
      Write-Host "nonDocsOnly: $nonDocsOnly"
      Write-Host "mixedChanges: $mixedChanges"

      # Output the results as pipeline variables
      Write-Host "##vso[task.setvariable variable=docsOnly;isOutput=true]$docsOnly"
      Write-Host "##vso[task.setvariable variable=nonDocsOnly;isOutput=true]$nonDocsOnly"
      Write-Host "##vso[task.setvariable variable=mixedChanges;isOutput=true]$mixedChanges"
    name: DetermineChanges