request_codeowners_review.yml

---
name: Request Code Owners Review

on:
  pull_request_target:
    types: ["opened", "synchronize"]

jobs:
  auto_request_review:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          ref: ${{ github.base_ref }}
          fetch-depth: 0

      - name: Fetch the PR's head ref
        run: |
          git fetch origin ${{ github.event.pull_request.head.sha }}:${{ github.event.pull_request.head.ref }}
          git checkout ${{ github.event.pull_request.head.ref }}

      - name: Auto request review
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          reviewers=""
          # Get changed files in this pull request
          echo "Checking base: ${{ github.event.pull_request.base.sha }}"
          echo "Checking head: ${{ github.event.pull_request.head.sha }}"
          for changed_file in $(git diff --name-only ${{ github.event.pull_request.base.sha }}...HEAD); do
            echo "Checking $changed_file"
            while read -r line; do
              # Get pattern of the files owned
              pattern=$(echo "$line" | awk '{print $1}')
              # Remove leading / from pattern and changed_file for comparison
              pattern="${pattern#/}"
              # Get owners of the files owned
              owners=$(echo "$line" | awk '{$1=""; print $0}' | xargs)
              # Remove leading / from changed_file for comparison
              changed_file="${changed_file#/}"
              if [[ "$changed_file" == $pattern* ]]; then
                # Add owners to reviewers
                echo "Found owners for $changed_file: $owners"
                reviewers="$reviewers $owners"
              fi
            done < .github/CODEOWNERS
          done
          # Remove duplicates and format for JSON
          reviewers=$(echo "$reviewers" | xargs -n1 | sort -u | xargs)
          # Remove @ from reviewers (it stays in the beginning of the username)
          reviewers_cleaned=${reviewers//@/}
          IFS=' ' read -ra reviewers_array <<< "$reviewers_cleaned"
          # Get username of PR author to exclude from reviewers
          pr_author="${{ github.event.pull_request.user.login }}"
          # Remove PR author from reviewers
          filtered_reviewers=()
          for reviewer in ${reviewers_array[@]}; do
            if [[ "$reviewer" != "$pr_author" ]]; then
              filtered_reviewers+=("$reviewer")
            fi
          done
          if [ ${#filtered_reviewers[@]} -gt 0 ]; then
            json_array=$(printf ',\"%s\"' "${filtered_reviewers[@]}")
            json_array="[${json_array:1}]" # Remove the leading comma
            echo "JSON array: $json_array"
            echo "Requesting review from: ${filtered_reviewers[*]}"
            echo https://api.github.com/repos/${{ github.repository }}/pulls/${{ github.event.pull_request.number }}/requested_reviewers
            curl -L \
              -D - \
              -X POST \
              -H "Authorization: Bearer $GITHUB_TOKEN" \
              -H "Accept: application/vnd.github+json" \
              https://api.github.com/repos/${{ github.repository }}/pulls/${{ github.event.pull_request.number }}/requested_reviewers \
              -d "{\"reviewers\": $json_array}"
          else
            echo "No reviewers found for the changed files."
          fi