CodeMention is a GitHub Action that mentions users and teams who subscribe to certain file changes on pull requests. See in pull requests in the codemention-test repo for examples of how this looks like.

This is similar to Codenotify, but this retrieves the diff via GitHub's REST API instead of using actions/checkout to clone the repo.

To use this GitHub Action, add a .github/codemention.yml file to your repo that contains mentions/notifications rules. An example looks like:

rules:
  - patterns: ['config/**']
    mentions: ['sysadmin']
  - patterns: ['db/migrate/**']
    mentions: ['cto', 'dba']
  - patterns: ['.github/**', 'spec/*.rb']
    mentions: ['ci']

Add a .github/workflows/codemention.yml file to your repo with the following:

name: codemention

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

jobs:
  codemention:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
    steps:
      - uses: tobyhs/codemention@v1
        with:
          githubToken: ${{ secrets.GITHUB_TOKEN }}

In order for CodeMention to mention teams, you need to use a GitHub personal access token that has organization permissions to read members. Replace the githubToken input with your personal access token.