index.ts

/**
 * Copyright 2020 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import * as core from '@actions/core';
import * as github from '@actions/github';
import type { GitUpdateRefResponseData, OctokitResponse } from '@octokit/types';

async function run(): Promise<void> {
  try {
    const githubToken = core.getInput('github-token');
    const sourceBranchName = core.getInput('source');
    const destBranchName = core.getInput('dest');

    const octokit = github.getOctokit(githubToken);
    const sourceBranchTip = await octokit.git.getRef({
      ...github.context.repo,
      ref: `heads/${sourceBranchName}`,
    });

    if (sourceBranchTip.data.object.type !== "commit") {
      throw new Error(`Expected branch ${sourceBranchName} to resolve to a commit. Got a ${sourceBranchTip.data.object.type}.`);
    }

    const sourceBranchSha = sourceBranchTip.data.object.sha;

    console.log(`Pushing ${sourceBranchName} (${sourceBranchSha}) to ${destBranchName}.`);

    let result: OctokitResponse<GitUpdateRefResponseData>;
    try {
      result = await octokit.git.updateRef({
        ...github.context.repo,
        ref: `heads/${destBranchName}`,
        sha: sourceBranchSha,
        force: true,
      });
    } catch (error: any) {
      if (error.message !== 'Reference does not exist') {
        throw error;
      }
      console.log(`${destBranchName} does not exist. Creating it.`);
      result = await octokit.git.createRef({
        ...github.context.repo,
        ref: `refs/heads/${destBranchName}`,
        sha: sourceBranchSha,
      });
    }

    console.log(`Set ${result.data.ref} to ${result.data.object.sha}.`);
  } catch (error: any) {
    core.setFailed(error.message);
  }
}

run();