GitHub action which tags users whose code has been altered in a PR. It uses git blame to determine who is the author of the code which has changed.

name: CI
on:
  pull_request:

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2
        with:
          ref: ${{ github.base_ref }}
          fetch-depth: 0
      - name: Blame Alert
        uses: molleer/blame-alert@master
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

User1 has made a new PR to a repo which is using molleer/blame-alert. He/she has deleted a few lines of code which User2 had written. When the PR is created, this comment is added to the PR by molleer/blame-alert.

If User1 only changes the code which he/she has added since before, molleer/blame-alert will not add an alert comment.