upmerge.yaml

# This workflow automates the process of upmerging changes from the current release branch to the edge branch.
# During the course of a release, the release branch is the default branch so that PRs can be immediately
# brought into the release without waiting for a new release. This workflow merges those changes into 
# the edge branch so that edge can be used as the basis for the next release branch.
#
# This workflow assumes that it is being triggered from the current release branch, but it could be triggered from
# any branch, and it uses that branch as the source branch for merging into the edge branch.
# The workflow is triggered manually via the workflow_dispatch event.
#
# The workflow performs the following steps:
# 1. Checks out the edge branch.
# 2. Configures git with a user name and email.
# 3. Creates a new branch from edge.
# 4. Merges changes from the branch executing the workflow into the edge branch created in the previous step.
# 5. Pushes the new branch if there are changes.
# 6. Creates a pull request to merge the new branch into edge.

# Example:
# The current release branch is v0.36. We are creating the new release for v0.37.
# The release person manually triggers this workflow from branch v0.36. The workflow runs, which does the following
# 1. A new branch is created named upmerge/2024-07-31-98b9. The source branch is edge.
# 2. Changes from branch v0.36 are merged into branch upmerge/2024-07-31-98b9.
# 3. A PR is created from branch upmerge/2024-07-31-98b9 --> edge. The workflow finishes and reports success.

name: Upmerge docs to edge

on:
  workflow_dispatch:

jobs:
  upmerge:
    name: Upmerge docs to edge
    runs-on: ubuntu-latest
    steps:

      # Checkout the edge branch
      - uses: actions/checkout@v4
        with:
          ref: edge
          # https://github.com/actions/checkout/issues/125#issuecomment-570254411
          fetch-depth: 0
      
      - name: Configure git
        run: |
          git config --global user.email "radiuscoreteam@service.microsoft.com"
          git config --global user.name "Radius CI Bot"
          gh auth login --with-token <<< "${{ secrets.GH_RAD_CI_BOT_PAT }}"

      # Create a new branch from edge. This branch will be used to PR back into edge.
      - name: Create new branch
        run: |
          export DATE=$(date +%Y-%m-%d)
          export RAND=$(openssl rand -hex 2)
          export BRANCH_NAME=upmerge/$DATE-$RAND
          echo "BRANCH_NAME=$BRANCH_NAME" >> $GITHUB_ENV
          git checkout -b $BRANCH_NAME
      
      # Merge changes from the github.ref branch, i.e., the branch from which the workflow is triggered. That
      # branch is assumed to be the current release branch, but could be any branch.
      # If there are no changes, stop the workflow.
      - name: Upmerge docs
        run: |
          export SOURCE_BRANCH=$(basename ${{ github.ref }})
          echo "Upmerging docs from $SOURCE_BRANCH to edge"
          git fetch origin $SOURCE_BRANCH
          
          git merge -m "Upmerge to edge" origin/$SOURCE_BRANCH
          
          if git diff --quiet edge; then
              echo "No changes to merge from $SOURCE_BRANCH to edge"
              echo "NO_CHANGES=true" >> $GITHUB_ENV
          else
              echo "Pushing $BRANCH_NAME for PR to edge"
              git reset HEAD docs/config.toml docs/layouts/partials/hooks/body-end.html
              git push --set-upstream origin $BRANCH_NAME
          fi
      
      # Create a PR from the new branch to edge
      - name: Create pull request
        if: env.NO_CHANGES != 'true'
        run: gh pr create --title "Upmerge to edge" --body "Upmerge to edge (kicked off by @${{ github.triggering_actor }})" --base edge --head $BRANCH_NAME