# WARNING:
# When extending this action, be aware that $GITHUB_TOKEN allows write access to
# the GitHub repository. This means that it should not evaluate user input in a
# way that allows code injection.

name: Backport

on:
  pull_request_target:
    types: [closed, labeled]

permissions:
  contents: read
  pull-requests: write

jobs:
  backport:
    name: Backport Pull Request
    if: vars.NIXPKGS_CI_APP_ID && github.event.pull_request.merged == true && (github.event.action != 'labeled' || startsWith(github.event.label.name, 'backport'))
    runs-on: ubuntu-24.04-arm
    steps:
      # Use a GitHub App to create the PR so that CI gets triggered
      # The App is scoped to Repository > Contents and Pull Requests: write for Nixpkgs
      - uses: actions/create-github-app-token@df432ceedc7162793a195dd1713ff69aefc7379e # v2.0.6
        id: app-token
        with:
          app-id: ${{ vars.NIXPKGS_CI_APP_ID }}
          private-key: ${{ secrets.NIXPKGS_CI_APP_PRIVATE_KEY }}
          permission-contents: write
          permission-pull-requests: write

      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          token: ${{ steps.app-token.outputs.token }}

      - name: Create backport PRs
        id: backport
        uses: korthout/backport-action@436145e922f9561fc5ea157ff406f21af2d6b363 # v3.2.0
        with:
          # Config README: https://github.com/korthout/backport-action#backport-action
          copy_labels_pattern: 'severity:\ssecurity'
          github_token: ${{ steps.app-token.outputs.token }}
          pull_description: |-
            Bot-based backport to `${target_branch}`, triggered by a label in #${pull_number}.

            * [ ] Before merging, ensure that this backport is [acceptable for the release](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#changes-acceptable-for-releases).
              * Even as a non-committer, if you find that it is not acceptable, leave a comment.

      - name: "Add 'has: port to stable' label"
        if: steps.backport.outputs.created_pull_numbers != ''
        env:
          # Not the app on purpose to avoid triggering another workflow run after adding this label
          GH_TOKEN: ${{ github.token }}
          REPOSITORY: ${{ github.repository }}
          NUMBER: ${{ github.event.number }}
        run: |
          gh api \
            --method POST \
            /repos/"$REPOSITORY"/issues/"$NUMBER"/labels \
            -f "labels[]=8.has: port to stable"