Push to protected branch from GitHub actions

It turns out that you really can't just git push from your GitHub actions if the repository has branch protection turned on or required checks before merging. Sorta makes sense, but still a PITA.

The solution that worked for me was to use a different token on checkout. Since the awesome GitHub CLI allows using a separate, higher-permissions token named GH_TOKEN (since depending on the command you use, you might need a different one than GITHUB_TOKEN), I decided to (ab)use the same:

An example workflow that uses this to generate a full changelog and push it to main on releases looks like this:

name: changelog
on:
  release:
    types: [released]

env:
  GH_TOKEN: ${{ secrets.GH_TOKEN }}

jobs:
  changelog:
    runs-on: ubuntu-latest
    steps:
      - name: 🔍 GH_TOKEN
        if: env.GH_TOKEN == ''
        env: 
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: echo "GH_TOKEN=${GITHUB_TOKEN}" >> $GITHUB_ENV

      - name: 🤘 checkout
        uses: actions/checkout@v2
        with:
          fetch-depth: 0
          ref: main
          token: ${{ env.GH_TOKEN }}

      - name: ⚙ changelog
        uses: faberNovel/github-changelog-generator-action@master
        with:
          options: --token ${{ secrets.GITHUB_TOKEN }} --o changelog.md

      - name: 🚀 changelog
        run: |
          git config --local user.name github-actions
          git config --local user.email [e-mail]
          git add changelog.md
          git commit -m "🖉 Update changelog with ${GITHUB_REF#refs/*/}"
          git push

Important parts:

• I default the GH_TOKEN envvar to a same-name secret, if present

• If it's not present, I default it to GITHUB_TOKEN

• Checkout always uses GH_TOKEN, which now may be a higher-permissions PAT than the default

• I do the defaulting since the push will succeed if the repository doesn't use branch protection for main and in that case I don't want to always force the presence of a GH_TOKEN secret.