increment-milestone-on-tag.yaml

name: Increment milestones on tag
on:
  create
permissions:
  issues: write # Required to update milestones

jobs:
  increment_milestone:
    if: github.event.ref_type == 'tag' && contains(github.event.ref,'-RC') == false
    runs-on: ubuntu-latest
    steps:
      - name: Close current milestone
        id: close-milestone
        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # 7.0.1
        with:
          script: |
            // Get the milestone title ("X.Y.Z") from tag name ("vX.Y.Z")
            const match = '${{github.event.ref}}'.match(/v(\d+\.\d+\.\d+)/i)
            if (!match) {
              core.setFailed('Failed to parse tag name into milestone title: ${{github.event.ref}}')
              return
            }
            const milestoneTitle = match[1]
            // Look for the milestone from its title
            const response = await github.rest.issues.listMilestones({
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'open'
            })
            if (!response.data || response.data.length == 0) {
              core.setFailed(`Failed to list milestones: ${response.status}`)
              return
            }
            const milestone = response.data.find(milestone => milestone.title == milestoneTitle)
            if (!milestone) {
              core.setFailed(`Failed to find milestone: ${milestoneTitle}`)
              return
            }
            // Close the milestone
            await github.rest.issues.updateMilestone({
              owner: context.repo.owner,
              repo: context.repo.repo,
              state: 'closed',
              milestone_number: milestone.number
            }).catch(error => {
              core.setFailed(`Failed to close milestone: ${error}`)
            })
            // Compute the next milestone version
            const versionNumbers = milestoneTitle.split('.').map(Number)
            if (versionNumbers[2] != 0) {
              core.info('Closing a patch version milestone. Not opening a new one.')
              return
            }
            versionNumbers[1]++
            const nextMilestoneTitle = versionNumbers.join('.')
            core.info(`Creating next version milestone: ${nextMilestoneTitle}`)
            // Create the next milestone
            await github.rest.issues.createMilestone({
              owner: context.repo.owner,
              repo: context.repo.repo,
              title: nextMilestoneTitle
            }).catch(error => {
              core.setFailed(`Failed to create milestone ${nextMilestoneTitle}: ${error}`)
            })