oppia/oppia

name: Revert Wiki Changes Made Through the Web Interface
on:
  gollum:
  workflow_dispatch:
jobs:
  revert:
    runs-on: ubuntu-22.04
    steps:
      - name: Retrieve authentication token
        id: get-token
        # SHA1 hash of the release-v0.0.1 commit.
        uses: oppia/get-github-app-token@8c3b19db0cdcd0f7fded7dd71e5e0429bf72df1a
        with:
          app_id: ${{ secrets.OPPIA_WIKI_SYNCHRONIZER_APP_ID }}
          private_key: ${{ secrets.OPPIA_WIKI_SYNCHRONIZER_APP_PRIVATE_KEY }}
      - uses: actions/checkout@v3
        with:
          repository: ${{github.repository_owner}}/oppia.wiki
          token: ${{ steps.get-token.outputs.token }}
          fetch-depth: 0
      - name: Add remote
        run: git remote add source https://github.com/${{github.repository_owner}}/oppia-web-developer-docs.git
      - name: Fetch remote
        run: git fetch source
      - name: Check for differences
        id: check-diff
        run: |
          delimiter="$(openssl rand -hex 8)"
          echo "diff<<$delimiter" >> "$GITHUB_OUTPUT"
          echo $(git log source/develop..origin/master) >> "$GITHUB_OUTPUT"
          echo "$delimiter" >> "$GITHUB_OUTPUT"
      - name: Revert commits
        if: ${{ steps.check-diff.outputs.diff != '' }}
        run: |
          git config user.name oppia-wiki-synchronizer[bot]
          # Email has the form id+name@users.noreply.github.com. The ID
          # can be retrieved from
          # https://api.github.com/users/oppia-wiki-synchronizer[bot].
          git config user.email 102317631+oppia-wiki-synchronizer[bot]@users.noreply.github.com
          git revert --no-commit source/develop..origin/master
          msg_file=$(mktemp)
          echo "Reverting the following changes made through the web interface:\n" > $msg_file
          git log source/develop..origin/master | while read line; do echo "    ${line}"; done >> $msg_file
          git commit -F $msg_file
      - name: Merge in development commits
        if: ${{ steps.check-diff.outputs.diff != '' }}
        # If a PR in the source repository was merged around the same time as a
        # change was made to the wiki through the web interface, its deployment
        # might fail before this job can revert the change. In that case, we
        # need to merge in those un-deployed changes to both the source and
        # deployment repositories.
        run: git merge source/develop
      - name: Push to deployment repository
        if: ${{ steps.check-diff.outputs.diff != '' }}
        run: git push source master:develop
      - name: Push to source repository
        if: ${{ steps.check-diff.outputs.diff != '' }}
        run: git push