This action will use rubocop --auto-gen-config to determine if new offenses were added in the current PR.

How it works:

• get a list of changes files.
• execute rubocop --auto-gen-config --format j to get the offenses for the changed files.
• move back before the merge commit.
• execute rubocop --auto-gen-config --format j to get the offenses for the changed files before the PR.
• parse again the extracted data and make a diff between old offenses and new offenses.
• print a summary containing the new offenses per file and cop.

• is recommended to create a separate github user that will only have read access and will post updates.
• generate a token that has read access.
• set the token in workflow definition as:

env:
 RTC_TOKEN: ${{ secrets.YOUR_TOKEN }}
 UPDATE_PR: true

  RTC_TOKEN: ${{ secrets.YOUR_TOKEN }} # token used for posting updates
  UPDATE_PR: bool # weather to post updates as comments or not
  FORCE_ERROR_EXIT: bool # force the job to be mark as failed if new offenses are added

# .github/workflows/rtc.yml

---
name: RuboCop TODO checker

on: [push]

jobs:
  rtc:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v1
      - uses: gimmyxd/rtc-action@0.2.0
        env:
          RTC_TOKEN: ${{ secrets.RTC_TOKEN }}
          UPDATE_PR: true