backport-to-release-branch.yml

# This workflow moves marked commits from a development branch to a release branch.
#
# Each commit in the development branch is cherry-picked to the release branch if the commit originates from a merged
# PR that is marked for backport.
#
# Merge conflicts should be rare. Should one occur, the changes are committed to a new branch with merge markers and
# then a PR is created into the target branch with those markers. The PR is labeled with "type:release-merge-conflict"
# to indicate that it needs manual resolution.
#
# The PR is expected to fail compilation and status checks (of course) due to the merge conflict markers. A human
# should then checkout the PR branch, resolve the conflicts, and push the changes back to the PR branch.
#
# NOTE: This file is automatically synchronized from Mu DevOps. Update the original file there
#       instead of the file in this repo.
#
# - Mu DevOps Repo: https://github.com/microsoft/mu_devops
# - File Sync Settings: https://github.com/microsoft/mu_devops/blob/main/.sync/Files.yml
#
# Copyright (c) Microsoft Corporation.
# SPDX-License-Identifier: BSD-2-Clause-Patent
#

name: Backport Commits to Release Branch

on:
  push:
    branches:
      - dev/202405

jobs:
  backport:
    name: Backport Dev Branch Commits to Release Branch
    runs-on: ubuntu-latest

    steps:
    - name: Checkout code
      uses: actions/checkout@v4
      with:
        fetch-depth: 0
        token: ${{ secrets.CHERRY_PICK_TOKEN }}

    - name: Determine Contribution Info
      id: backport_info
      uses: actions/github-script@v7
      with:
        script: |
          const BOLD = "\u001b[1m";
          const GREEN = "\u001b[32m";

          const ref = process.env.GITHUB_REF;
          const sourceBranchName = ref.replace('refs/heads/', '');
          const targetBranchName = sourceBranchName.replace('dev', 'release');

          const commits = context.payload.commits;
          const commitCount = commits.length;

          if (commits.length === 0) {
            console.log(GREEN + "No commits found. Exiting workflow.");
            core.setOutput('backport_needed', 'false');
            process.exit(0);
          }

          console.log(`Source branch name is ${sourceBranchName}`);
          console.log(`Target branch name is ${targetBranchName}\n`);

          core.startGroup(`${commitCount} Commit(s) in this Contribution`);
          commits.forEach((commit, index) => {
            console.log(BOLD + `Commit #${index + 1}: ${commit.id}`);
            console.log(`${commit.message}\n`);
          });
          core.endGroup();

          core.setOutput('backport_needed', 'true');
          core.setOutput('source_branch_name', sourceBranchName);
          core.setOutput('target_branch_name', targetBranchName);
          core.setOutput('first_commit_id', commits[0].id);
          core.setOutput('commits', JSON.stringify(commits));
          core.setOutput('commit_by_id', commits.map(commit => commit.id).join(' '));
          core.setOutput('commit_messages', commits.map(commit => `${commit.message.split('\n')[0]}\n${commit.message.split('\n').slice(1).join('\n')}\n---`).join('\n'));
          core.setOutput('commit_count', commitCount);

    - name: Check if Backport is Requested
      id: backport_check
      uses: actions/github-script@v7
      with:
        script: |
          if (${{ steps.backport_info.outputs.backport_needed }} === 'false') {
            core.setOutput('backport_needed', 'false');
            process.exit(0);
          }

          const BOLD = "\u001b[1m";
          const GREEN = "\u001b[32m";
          const MAGENTA = "\u001b[35m";

          const response = await github.request("GET /repos/${{ github.repository }}/commits/${{ steps.backport_info.outputs.first_commit_id }}/pulls", {
                  headers: {
                    authorization: `token ${process.env.GITHUB_TOKEN}`
                  }
                });

          const prNumber = response.data.length > 0 ? response.data[0].number : null;

          console.log(`Associated Pull Request Number: ${prNumber}\n`);

          if (!prNumber) {
            console.log(GREEN + "No associated pull request found. Nothing to backport! Exiting.");
            core.setOutput('backport_needed', 'false');
            process.exit(0);
          }

          const { data: pull } = await github.rest.pulls.get({
            owner: context.repo.owner,
            repo: context.repo.repo,
            pull_number: prNumber
            });

          core.startGroup(`${pull.labels.length} Label(s) in the PR`);
          pull.labels.forEach((label, index) => {
            console.log(BOLD + `Label #${index + 1}: \"${label.name}\"`);
            });
          core.endGroup();

          const label = pull.labels.find(l => l.name === 'type:backport');
          if (!label) {
            console.log(GREEN + "Changes are not requested for backport. Exiting.");
            core.setOutput('backport_needed', 'false');
            process.exit(0);
          }

          console.log(MAGENTA + "The changes are requested for backport. Proceeding with backport.\n");

          core.setOutput('pr_number', prNumber);
          core.setOutput('backport_needed', 'true');
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

    - name: Checkout a Local ${{ steps.backport_info.outputs.target_branch_name }} Branch (Destination Branch)
      if: steps.backport_check.outputs.backport_needed == 'true'
      run: |
        git config --global user.email "mubot@microsoft.com"
        git config --global user.name "Project Mu Bot"
        git checkout -b ${{ steps.backport_info.outputs.target_branch_name }} origin/${{ steps.backport_info.outputs.target_branch_name }}

    - name: Check for Merge Conflicts
      if: steps.backport_check.outputs.backport_needed == 'true'
      id: merge_conflicts
      run: |
        conflict=false

        for commit in ${{ steps.backport_info.outputs.commit_by_id }}; do
          echo -e "\nAttempting to cherry-pick commit $commit..."

          set +e
          cherry_pick_output=$( { git cherry-pick $commit; } 2>&1 )
          set -e

          if echo "$cherry_pick_output" | grep -q "The previous cherry-pick is now empty"; then
            echo "Cherry-picking $commit resulted in an empty commit. Skipping it.";
            git cherry-pick --skip;
          elif echo "$cherry_pick_output" | grep -q "Merge conflict in"; then
            echo "Merge conflict detected for commit $commit! Committing it with conflict markers.";
            original_author=$(git log -1 --pretty=format:'%an <%ae>' $commit)
            original_date=$(git log -1 --pretty=format:'%ad' --date=iso-strict $commit)
            original_message=$(git log -1 --pretty=%B $commit)
            git add -A
            GIT_COMMITTER_DATE="$original_date" GIT_AUTHOR_DATE="$original_date" git commit --author="$original_author" -m "[CONFLICT] $original_message"
            conflict=true;
          else
            echo "$commit was cherry-picked successfully.";
          fi
        done

        echo "merge_conflict=$conflict" >> $GITHUB_ENV
      continue-on-error: true

    - name: Push to ${{ steps.backport_info.outputs.target_branch_name }} if No Conflicts
      if: steps.backport_check.outputs.backport_needed == 'true' && env.merge_conflict == 'false'
      run: |
        git push origin ${{ steps.backport_info.outputs.target_branch_name }}:${{ steps.backport_info.outputs.target_branch_name }}

    - name: Generate a Unique PR Branch Name (On Merge Conflict)
      if: steps.backport_check.outputs.backport_needed == 'true' && env.merge_conflict == 'true'
      id: merge_conflict_branch_info
      run: |
        TIMESTAMP=$(date +%Y%m%d%H%M%S)
        branch_name="merge-conflict/${{ steps.backport_info.outputs.target_branch_name }}/$TIMESTAMP"

        echo -e "\nMerge conflict branch name generated: $branch_name"

        git branch -m $branch_name
        git push origin refs/heads/$branch_name:refs/heads/$branch_name

        echo "branch_name=$branch_name" >> $GITHUB_OUTPUT

    - name: Create Pull Request (On Merge Conflict)
      if: steps.backport_check.outputs.backport_needed == 'true' && env.merge_conflict == 'true'
      run: |
        PR_BRANCH="${{ steps.merge_conflict_branch_info.outputs.branch_name }}"
        BASE_BRANCH="${{ steps.backport_info.outputs.target_branch_name }}"
        PR_TITLE="Manual Merge Conflict Resolution for ${{ steps.backport_info.outputs.commit_count }} Commits into ${{ steps.backport_info.outputs.target_branch_name }}"
        PR_BODY="This pull request is created to resolve the merge conflict that occurred while backporting the commits
        from ${{ steps.backport_info.outputs.source_branch_name }} to ${{ steps.backport_info.outputs.target_branch_name }}.

        **Commits in this PR:**

        ${{ steps.backport_info.outputs.commit_messages }}

        **Instructions:**

        1. Checkout this PR branch locally.
        2. Verify all commits that are being backported are present in the branch.
        3. Resolve the merge conflict markers in the files.
        4. Commit the changes.
        5. Push the changes back to this PR branch.

        **Note:**

        If it is too complicated to use this branch as-is, then simply attempt to merge the same set of commits into
        the release branch locally, resolve the conflicts, and force push the changes to the PR branch."

        echo "PR Title: $PR_TITLE"
        echo "PR Body: $PR_BODY"
        echo "PR Branch: $PR_BRANCH"
        echo "Base Branch: $BASE_BRANCH"

        curl -s -X POST https://api.github.com/repos/${{ github.repository }}/pulls \
        -H "Authorization: token $CHERRY_PICK_TOKEN" \
        -H "Content-Type: application/json" \
        -d "{\"title\":\"$PR_TITLE\",\"body\":\"$PR_BODY\",\"head\":\"$PR_BRANCH\",\"base\":\"$BASE_BRANCH\",\"labels\":[\"type:release-merge-conflict\"]}"
      env:
        CHERRY_PICK_TOKEN: ${{ secrets.CHERRY_PICK_TOKEN }}