delete-closed-pr-branches.yml

# Fires immediately when a PR is closed without merging and deletes the head
# branch — provided it lives on this repo (not a fork) and is not protected.
# Merged PRs are excluded because the repo's "automatically delete head branches"
# setting already handles those.
#
# Fork branches are skipped at the job level via the `if:` condition because
# we don't own them and the API would return a 403.
#
# To test without deleting anything, trigger this workflow manually via
# workflow_dispatch and supply a branch name. Manual runs always dry-run
# — they log "Would delete: <branch>" without touching anything.

name: Delete closed PR branches

on:
  pull_request:
    types: [closed]
  workflow_dispatch:
    inputs:
      branch:
        description: "Branch name to dry-run against"
        required: true
        type: string

permissions:
  contents: write

jobs:
  delete-branch:
    if: github.event_name == 'workflow_dispatch' || (github.event.pull_request.head.repo.full_name == github.repository && github.event.pull_request.merged == false)
    runs-on: ubuntu-latest
    steps:
      - name: Delete branch associated with closed PR
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          DRY_RUN: ${{ github.event_name == 'workflow_dispatch' && 'true' || 'false' }}
        run: |
          branch="${{ github.event_name == 'workflow_dispatch' && inputs.branch || github.event.pull_request.head.ref }}"

          if [ "$DRY_RUN" = "true" ]; then
            echo "*** DRY RUN — no branches will be deleted ***"
          fi

          protected=$(gh api "repos/$GITHUB_REPOSITORY/branches?protected=true&per_page=100" \
            | jq -r '.[].name')

          if echo "$protected" | grep -qx "$branch"; then
            echo "Skipped (protected): $branch"
            exit 0
          fi

          if [ "$DRY_RUN" = "true" ]; then
            echo "Would delete: $branch"
            exit 0
          fi

          gh api "repos/$GITHUB_REPOSITORY/git/refs/heads/$branch" \
            -X DELETE 2>/dev/null \
            && echo "Deleted: $branch" \
            || echo "Skipped (already gone): $branch"