pr-manage-stale.yml

# Contributors: @wicksipedia @william-liebenberg @GordonBeeming
# < as per SSW.Rules: https://www.ssw.com.au/rules/standard-set-of-pull-request-workflows/ >

name: "PR - Manage Stale PRs"

on:
  pull_request:
    types: [opened, ready_for_review]
    branches: [main]

  schedule:
    # run every 2nd hour
    # https://crontab.guru/#0_0/2_*_*_*
    - cron: "0 0/2 * * *"

  workflow_dispatch:

permissions:
  contents: read
  issues: write
  repository-projects: read
  pull-requests: write

jobs:
  new_pull_request:
    if: ${{ github.event_name == 'pull_request' }}
    runs-on: ubuntu-latest
    steps:            
      - name: Checkout
        uses: actions/checkout@v4
    
      - name: add label
        shell: pwsh
        run: |
          $thisPr = gh pr view ${{ github.event.pull_request.number }} --json number,isCrossRepository | ConvertFrom-Json
          if ($thisPr.isCrossRepository) {
              Write-Output "Skipping cross repository PR"
              return
          }

          # ensure labels exist - create them if they don't
          # https://docs.github.com/en/rest/reference/issues#create-a-label      
          $label = "Age: 🥚 - New"
          $description = "About 2 hours old"
          Write-Output "Ensuring label exists: $label ($description))"
          gh api repos/${{ github.repository }}/labels -f name="$label" -f color=000000 -f description="$description"

          Write-Output "Adding label: $label"
          gh pr edit $thisPr.number --add-label "$label"
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          

  scheduled_run:
    if: ${{ github.event_name != 'pull_request' }}
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
    
      - name: Find PRs
        shell: pwsh
        run: |
          # labels for each age in hours (as an array)
          $labels = @(
              'Age: 🥚 - New', # 2 hours
              'Age: 🐣 - Young', # 4 hours
              'Age: 🐥 - Adolescent', # 8 hours
              'Age: 🐤 - Mature', # 16 hours
              'Age: 🐓 - Old', # 32 hours
              'Age: 🍗 - Ancient', # 64 hours
              'Age: 🦖 - Extinct' # 128 hours
          )

          # ensure labels exist - create them if they don't
          # https://docs.github.com/en/rest/reference/issues#create-a-label
          $index = 0
          $labels | ForEach-Object {
              $label = $_
              $description = "About $([math]::Pow(2, $index + 1)) hours old"
              Write-Output "Ensuring label exists: $label ($description))"
              gh api repos/${{ github.repository }}/labels -f name="$label" -f color=000000 -f description="$description"
              $index++
          }
          $mergeDebtLabelText = "Merge Debt"
          $mergeDebtLabel = "🔥 $mergeDebtLabelText"
          $description = "This PR contains merge debt, see https://www.ssw.com.au/rules/merge-debt/"
          Write-Output "Ensuring label exists: $mergeDebtLabel ($description))"
          gh api repos/${{ github.repository }}/labels -f name="$mergeDebtLabel" -f color=000000 -f description="$description"

          $now = Get-Date -AsUTC

          # use github cli to get a list of open pull requests
          $openPullRequests = gh pr list -s open --json title,number,createdAt,labels,author

          Write-Output "Open pull requests:"

          # for each pull request in the list calculate the age in hours
          $openPullRequests | ConvertFrom-Json | ForEach-Object {
              $title = $_.title
              $number = $_.number
              $createdAt = $_.createdAt
              $prLabels = $_.labels
              $author = $_.author
              $ageInHours = [int]($now - $createdAt).TotalHours

              if ($ageInHours -eq 0) {
                  Write-Output "$($number): $title ($ageInHours hours old) - skipping"
                  return
              }    

              Write-Output "$($number): $title ($ageInHours hours old)"

              # find age as nearest doubling number of 2
              $ageAsPoints = [math]::Ceiling([math]::Log($ageInHours, 2))
              Write-Output "ageAsPoints: $([math]::Pow(2,$ageAsPoints))"

              # if the age is 0, then set it to 1
              if ($ageAsPoints -eq 0) {
                  $ageAsPoints = 1
              }

              # if the age is greater than the length of the labels array
              # then set it to the last label
              if ($ageAsPoints -gt $labels.Length) {
                  $ageAsPoints = $labels.Length
              }

              $newLabel = $labels[$ageAsPoints - 1]
              Write-Output "Adding label: $newLabel"

              # all labels except the new label
              $allLabels = ($labels | Where-Object { $_ -ne $newLabel }) -join ','
              Write-Output "Removing labels: $allLabels"
              gh pr edit $number --add-label "$newLabel" --remove-label "$allLabels"

              $mergeLabelExists = $prLabels | Where-Object { $_.name.trim().EndsWith($mergeDebtLabelText) }
              if ($ageInHours -ge 36 -and $mergeLabelExists -eq $null -and $author.is_bot -eq $false) { # after 36 hours old
                  Write-Output "Adding comment to PR: $number"
                  gh pr edit $number --add-label "$mergeDebtLabel"
                  $comment = @"
          Howzit @$($author.login),

          This PR has been here a while. 

          [Did you know you should avoid merge debt?](https://www.ssw.com.au/rules/merge-debt/)          

          1. Please action (e.g. get a review) and merge or close 

          Thanks!
          "@
                  Set-Content -Path "comment.md" -Value $comment
                  gh pr comment $number --body-file comment.md
              }
              
              Write-Output ""
          }

        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}