sync-and-rebase-pr-from-fork.yml

name: Sync and rebase PR from fork

on:
  workflow_dispatch:
    inputs:
      PR_NUMBER:
        required: true
        description: "Number of the PR from the fork"

jobs:
  sync-and-rebase-pr-from-fork:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3
        with:
          fetch-depth: 0

      - name: Setup Git
        run: |
          git config user.name brave-builds
          git config user.email devops@brave.com
          git config push.default simple

      - name: Sync and rebase PR from fork
        env:
          GITHUB_TOKEN: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
          PR_NUMBER: ${{ inputs.PR_NUMBER }}
        run: |
          set -x
          JQ="jq -e -r"

          gh_pr_view=$(gh pr view "$PR_NUMBER" --json baseRefName,headRefName,headRepository,headRepositoryOwner,id,isCrossRepository,url)

          baseRefName=$($JQ ".baseRefName" <<<"$gh_pr_view")
          headRefName=$($JQ ".headRefName" <<<"$gh_pr_view")
          headRepositoryName=$($JQ ".headRepository.name" <<<"$gh_pr_view")
          headRepositoryOwnerLogin=$($JQ ".headRepositoryOwner.login" <<<"$gh_pr_view")
          isCrossRepository=$($JQ ".isCrossRepository" <<<"$gh_pr_view")
          url=$($JQ ".url" <<<"$gh_pr_view")

          [[ "$isCrossRepository" = "true" ]] || { echo "PR is not cross repo. Exiting!"; exit 1; }

          git remote add contributor "https://github.com/$headRepositoryOwnerLogin/$headRepositoryName.git" || :
          contribHeadRefName="contributor-$headRepositoryOwnerLogin-$headRefName"
          git fetch --no-tags contributor +"$headRefName":"$contribHeadRefName"

          # Rebase the branch with the latest targeting branch HEAD
          git checkout "$contribHeadRefName"
          git fetch origin "$baseRefName"
          if ! git rebase FETCH_HEAD; then
            echo "Rebase conflict detected. Please resolve the conflicts and push the changes to your fork. Exiting!"
            exit 1
          fi
          git push -f origin "$contribHeadRefName"

          existing_prs=$(gh pr list -H "$contribHeadRefName" --json number)
          if [[ "$existing_prs" = "[]" ]]; then
            gh pr create \
              --draft \
              --base "$baseRefName" \
              --head "$contribHeadRefName" \
              --assignee "$headRepositoryOwnerLogin" \
              --title "CI run for contributor PR #$PR_NUMBER" \
              --body \
          "## Description
          This PR is created to run CI on the changes proposed in PR #$PR_NUMBER by @$headRepositoryOwnerLogin.

          **This PR should not be merged.**"
          fi