From db1cc43cb3ec73c44dc2f38d05911ee76bd420d6 Mon Sep 17 00:00:00 2001
From: Patrik Oldsberg <poldsberg@gmail.com>
Date: Wed, 2 Nov 2022 13:04:48 +0100
Subject: [PATCH] scripts: add script for creating a patch release from a PR

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
---
 scripts/patch-release-for-pr.js | 156 ++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100755 scripts/patch-release-for-pr.js

diff --git a/scripts/patch-release-for-pr.js b/scripts/patch-release-for-pr.js
new file mode 100755
index 0000000000..fcfef0c6a7
--- /dev/null
+++ b/scripts/patch-release-for-pr.js
@@ -0,0 +1,156 @@
+#!/usr/bin/env node
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+const fs = require('fs-extra');
+const path = require('path');
+const semver = require('semver');
+const { Octokit } = require('@octokit/rest');
+const { execFile: execFileCb } = require('child_process');
+const { promisify } = require('util');
+
+const execFile = promisify(execFileCb);
+
+const owner = 'backstage';
+const repo = 'backstage';
+const rootDir = path.resolve(__dirname, '..');
+
+const octokit = new Octokit({
+  auth: process.env.GITHUB_TOKEN,
+});
+
+async function run(command, ...args) {
+  const { stdout, stderr } = await execFile(command, args, {
+    cwd: rootDir,
+  });
+
+  if (stderr) {
+    console.error(stderr);
+  }
+
+  return stdout.trim();
+}
+
+/**
+ * Finds the current stable release version of the repo, looking at
+ * the current commit and backwards, finding the first commit were a
+ * stable version is present.
+ */
+async function findCurrentReleaseVersion() {
+  const rootPkgPath = path.resolve(rootDir, 'package.json');
+  const pkg = await fs.readJson(rootPkgPath);
+
+  if (!semver.prerelease(pkg.version)) {
+    return pkg.version;
+  }
+
+  const { stdout: revListStr } = await execFile('git', [
+    'rev-list',
+    'HEAD',
+    '--',
+    'package.json',
+  ]);
+  const revList = revListStr.trim().split(/\r?\n/);
+
+  for (const rev of revList) {
+    const { stdout: pkgJsonStr } = await execFile('git', [
+      'show',
+      `${rev}:package.json`,
+    ]);
+    if (pkgJsonStr) {
+      const pkgJson = JSON.parse(pkgJsonStr);
+      if (!semver.prerelease(pkgJson.version)) {
+        return pkgJson.version;
+      }
+    }
+  }
+
+  throw new Error('No stable release found');
+}
+
+async function main(prNumberStr) {
+  const prNumber = parseInt(prNumberStr, 10);
+  if (!Number.isInteger(prNumber)) {
+    throw new Error('Must provide a PR number as the first argument');
+  }
+  console.log(`PR number: ${prNumber}`);
+
+  if (await run('git', 'status', '--porcelain')) {
+    throw new Error('Cannot run with a dirty working tree');
+  }
+
+  const release = await findCurrentReleaseVersion();
+  console.log(`Patching release ${release}`);
+
+  await run('git', 'fetch');
+
+  const patchBranch = `patch/v${release}`;
+  try {
+    await run('git', 'checkout', `origin/${patchBranch}`);
+  } catch {
+    await run('git', 'checkout', '-b', patchBranch, `v${release}`);
+    await run('git', 'push', 'origin', '-u', patchBranch);
+  }
+
+  const { data } = await octokit.pulls.get({
+    owner,
+    repo,
+    pull_number: prNumber,
+  });
+
+  const headSha = data.head.sha;
+  if (!headSha) {
+    throw new Error('head sha not available');
+  }
+  const baseSha = data.base.sha;
+  if (!baseSha) {
+    throw new Error('base sha not available');
+  }
+  const mergeBaseSha = await run('git', 'merge-base', headSha, baseSha);
+
+  // Create new branch, apply changes from all commits on PR branch, commit, push
+  const branchName = `patch-release-pr-${prNumber}`;
+  await run('git', 'checkout', '-b', branchName);
+
+  const logLines = await run(
+    'git',
+    'log',
+    `${mergeBaseSha}...${headSha}`,
+    '--reverse',
+    '--pretty=%H',
+  );
+  for (const logSha of logLines.split(/\r?\n/)) {
+    await run('git', 'cherry-pick', '-n', logSha);
+  }
+  await run('git', 'commit', '--signoff', '-m', `Patch from PR #${prNumber}`);
+
+  console.log('Running "yarn release" ...');
+  await run('yarn', 'release');
+
+  await run('git', 'add', '.');
+  await run('git', 'commit', '--signoff', '-m', 'Generate Release');
+
+  await run('git', 'push', 'origin', '-u', branchName);
+
+  console.log(
+    `https://github.com/backstage/backstage/compare/${patchBranch}...${branchName}?expand=1&body=This%20release%20fixes%20an%20issue%20where&title=Patch%20release%20of%20%23${prNumber}`,
+  );
+}
+
+main(process.argv.slice(2)).catch(error => {
+  console.error(error.stack || error);
+  process.exit(1);
+});