create-cherry-pick-pr.yml

name: Create cherry pick PR

on:
  repository_dispatch:
    types: [create-cherry-pick-pr]
  workflow_dispatch:
    inputs:
      pr:
        description: PR number to cherry-pick
        required: true
        type: number
      target_branch:
        description: Target branch to cherry-pick to
        required: true
        type: string
      requesting_user:
        description: User who requested the cherry-pick
        required: true
        type: string

permissions:
  contents: read

# Ensure scripts are run with pipefail. See:
# https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#exit-codes-and-error-action-preference
defaults:
  run:
    shell: bash

jobs:
  open-pr:
    runs-on: ubuntu-latest
    if: github.repository == 'microsoft/TypeScript'

    steps:
      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
          filter: blob:none # https://github.blog/2020-12-21-get-up-to-speed-with-partial-clone-and-shallow-clone/
          fetch-depth: 0 # Default is 1; need to set to 0 to get the benefits of blob:none.
          token: ${{ secrets.TS_BOT_GITHUB_TOKEN }}

      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
        env:
          PR: ${{ inputs.pr || github.event.client_payload.pr }}
          TARGET_BRANCH: ${{ inputs.target_branch || github.event.client_payload.target_branch }}
          REQUESTING_USER: ${{ inputs.requesting_user || github.event.client_payload.requesting_user }}
        with:
          retries: 3
          github-token: ${{ secrets.TS_BOT_GITHUB_TOKEN }}
          script: |
            const { PR, TARGET_BRANCH, REQUESTING_USER } = process.env;

            const pr = await github.rest.pulls.get({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: +PR,
            });

            if (!pr.data.merge_commit_sha) throw new Error("No merge commit sha found");

            const pickBranch = `cherry-pick/${PR}/${TARGET_BRANCH}`;

            const title = `🤖 Pick PR #${PR} (${pr.data.title.substring(0, 35)}${pr.data.title.length > 35 ? "..." : ""}) into ${TARGET_BRANCH}`;

            await exec.exec("git", ["config", "user.email", "typescriptbot@microsoft.com"]);
            await exec.exec("git", ["config", "user.name", "TypeScript Bot"]);
            await exec.exec("git", ["switch", "--detach", `origin/${TARGET_BRANCH}`]);
            await exec.exec("git", ["switch", "-c", pickBranch]);
            await exec.exec("git", ["cherry-pick", "-m", "1", pr.data.merge_commit_sha]);
            await exec.exec("git", ["push", "--force", "--set-upstream", "origin", pickBranch]);

            const existingPulls = await github.rest.pulls.list({
              owner: context.repo.owner,
              repo: context.repo.repo,
              head: `${context.repo.owner}:${pickBranch}`,
            });

            if (existingPulls.data.length === 0) {
              console.log(`No existing PRs found for ${pickBranch}`);

              const body = `This cherry-pick was triggered by a request on #${PR}.\n\nPlease review the diff and merge if no changes are unexpected.`;

              const newPr = await github.rest.pulls.create({
                owner: context.repo.owner,
                repo: context.repo.repo,
                base: TARGET_BRANCH,
                head: pickBranch,
                title,
                body,
                assignees: ["DanielRosenwasser"],
                reviewers: ["DanielRosenwasser", REQUESTING_USER],
              });

              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: +PR,
                body: `Hey @${REQUESTING_USER}, I've created #${newPr.data.number} for you.`,
              });
            }
            else {
              const existing = existingPulls.data[0];
              console.log(`Found existing PR #${existing.number} for ${pickBranch}`);

              await github.rest.pulls.update({
                owner: context.repo.owner,
                repo: context.repo.repo,
                pull_number: existing.number,
                title,
              });

              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: +PR,
                body: `Hey @${REQUESTING_USER}, I've updated #${existing.number} for you.`,
              });
            }

      - run: |
          MESSAGE="Hey @$REQUESTING_USER, I was unable to cherry-pick this PR."
          MESSAGE+=$'\n\n'
          MESSAGE+="Check the logs at: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"

          gh pr comment "$PR" --repo ${{ github.repository }} --body "$MESSAGE"
        if: ${{ failure() }}
        env:
          PR: ${{ inputs.pr || github.event.client_payload.pr }}
          TARGET_BRANCH: ${{ inputs.target_branch || github.event.client_payload.target_branch }}
          REQUESTING_USER: ${{ inputs.requesting_user || github.event.client_payload.requesting_user }}
          GH_TOKEN: ${{ secrets.TS_BOT_GITHUB_TOKEN }}