angular-cn/tools/rebase-pr.js

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/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
/**
* **Usage:**
* ```
* node rebase-pr <github-repository> <pull-request-number>
* ```
* **Example:**
* ```
* node rebase-pr angular/angular 123
* ```
*
* Rebases the current branch on top of the GitHub PR target branch.
*
* **Context:**
* Since a GitHub PR is not necessarily up to date with its target branch, it is useful to rebase
* prior to testing it on CI to ensure more up to date test results.
*
* **Implementation details:**
* This script obtains the base for a GitHub PR via the
* [GitHub PR API](https://developer.github.com/v3/pulls/#get-a-single-pull-request), then
* fetches that branch, and rebases the current branch on top of it.
*
* **NOTE:**
* This script cannot use external dependencies or be compiled because it needs to run before the
* environment is setup.
* Use only features supported by the NodeJS versions used in the environment.
*/
// This script uses `console` to print messages to the user.
// tslint:disable:no-console
// Imports
const util = require('util');
const https = require('https');
const child_process = require('child_process');
const exec = util.promisify(child_process.exec);
// CLI validation
if (process.argv.length != 4) {
console.error(`This script requires the GitHub repository and PR number as arguments.`);
console.error(`Example: node tools/rebase-pr.js angular/angular 123`);
process.exitCode = 1;
return;
}
// Run
_main(...process.argv.slice(2)).catch(err => {
console.log('Failed to rebase on top of target branch.\n');
console.error(err);
process.exitCode = 1;
});
// Helpers
async function _main(repository, prNumber) {
console.log(`Getting refs and SHAs for PR ${prNumber} on ${repository}.`);
const target = await determineTargetRefAndSha(repository, prNumber);
console.log(`Fetching target branch: ${target.baseRef}.`);
await exec(`git fetch origin ${target.baseRef}`);
// The sha of the latest commit on the target branch.
const {stdout: shaOfTargetBranchLatest} = await exec(`git rev-parse origin/${target.baseRef}`);
// The sha of the latest commit on the PR.
const {stdout: shaOfPRLatest} = await exec(`git rev-parse HEAD`);
// The first common SHA in the history of the target branch and the latest commit in the PR.
const {stdout: commonAncestorSha} =
await exec(`git merge-base origin/${target.baseRef} ${shaOfPRLatest}`);
// Log known refs and shas
console.log(`--------------------------------`);
console.log(` Target Branch: ${target.baseRef}`);
console.log(` Latest Commit for Target Branch: ${shaOfTargetBranchLatest.trim()}`);
console.log(` Latest Commit for PR: ${shaOfPRLatest.trim()}`);
console.log(` First Common Ancestor SHA: ${commonAncestorSha.trim()}`);
console.log(`--------------------------------`);
console.log();
// Get the count of commits between the latest commit from origin and the common ancestor SHA.
const {stdout: commitCount} =
await exec(`git rev-list --count origin/${target.baseRef}...${commonAncestorSha.trim()}`);
console.log(`Checking ${commitCount.trim()} commits for changes in the CircleCI config file.`);
// Check if the files changed between the latest commit from origin and the common ancestor SHA
// includes the CircleCI config.
const {stdout: circleCIConfigChanged} = await exec(
`git diff --name-only origin/${target.baseRef} ${commonAncestorSha.trim()} -- .circleci/config.yml`);
if (!!circleCIConfigChanged) {
throw Error(`
CircleCI config on ${target.baseRef} has been modified since commit ${commonAncestorSha.slice(0, 7)},
which this PR is based on.
Please rebase the PR on ${target.baseRef} after fetching from upstream.
Rebase instructions for PR Author, please run the following commands:
git fetch upstream ${target.baseRef};
git checkout ${target.headRef};
git rebase upstream/${target.baseRef};
git push --force-with-lease;
`);
} else {
console.log('No change found in the CircleCI config file, continuing.');
}
console.log();
// Rebase the PR.
console.log(`Rebasing current branch on ${target.baseRef}.`);
await exec(`git rebase origin/${target.baseRef}`);
console.log('Rebase successful.');
}
async function requestDataFromGithub(url) {
// GitHub requires a user agent: https://developer.github.com/v3/#user-agent-required
const options = {headers: {'User-Agent': 'angular'}};
return new Promise((resolve, reject) => {
https
.get(
url, options,
(res) => {
const {statusCode} = res;
const contentType = res.headers['content-type'];
let rawData = '';
res.on('data', (chunk) => { rawData += chunk; });
res.on('end', () => {
let error;
if (statusCode !== 200) {
error = new Error(
`Request Failed.\nStatus Code: ${statusCode}.\nResponse: ${rawData}`);
} else if (!/^application\/json/.test(contentType)) {
error = new Error(
'Invalid content-type.\n' +
`Expected application/json but received ${contentType}`);
}
if (error) {
reject(error);
return;
}
try {
resolve(JSON.parse(rawData));
} catch (e) {
reject(e);
}
});
})
.on('error', (e) => { reject(e); });
});
}
async function determineTargetRefAndSha(repository, prNumber) {
const pullsUrl = `https://api.github.com/repos/${repository}/pulls/${prNumber}`;
const result = await requestDataFromGithub(pullsUrl);
return {
baseRef: result.base.ref,
baseSha: result.base.sha,
headRef: result.head.ref,
headSha: result.head.sha,
};
}