add release proposal script for use locally (#4853)

.gitignore

@@ -106,6 +106,7 @@ typings/
 
 # End of https://www.gitignore.io/api/node,macos,visualstudiocode
 
+.github/notes
 .next
 package-lock.json
 out

scripts/release/proposal.js

@@ -0,0 +1,128 @@
+'use strict'
+
+/* eslint-disable no-console */
+
+// TODO: Support major versions.
+
+const { execSync } = require('child_process')
+const fs = require('fs')
+const path = require('path')
+
+// Helpers for colored output.
+const log = msg => console.log(msg)
+const success = msg => console.log(`\x1b[32m${msg}\x1b[0m`)
+const error = msg => console.log(`\x1b[31m${msg}\x1b[0m`)
+const whisper = msg => console.log(`\x1b[90m${msg}\x1b[0m`)
+
+const currentBranch = capture('git branch --show-current')
+const releaseLine = process.argv[2]
+
+// Validate release line argument.
+if (!releaseLine || releaseLine === 'help' || releaseLine === '--help') {
+  log('Usage: node scripts/release/proposal <release-line> [release-type]')
+  process.exit(0)
+} else if (!releaseLine?.match(/^\d+$/)) {
+  error('Invalid release line. Must be a whole number.')
+  process.exit(1)
+}
+
+// Make sure the release branch is up to date to prepare for new proposal.
+// The main branch is not automatically pulled to avoid inconsistencies between
+// release lines if new commits are added to it during a release.
+run(`git checkout v${releaseLine}.x`)
+run('git pull')
+
+const diffCmd = [
+  'branch-diff',
+  '--user DataDog',
+  '--repo dd-trace-js',
+  isActivePatch()
+    ? `--exclude-label=semver-major,semver-minor,dont-land-on-v${releaseLine}.x`
+    : `--exclude-label=semver-major,dont-land-on-v${releaseLine}.x`
+].join(' ')
+
+// Determine the new version.
+const [lastMajor, lastMinor, lastPatch] = require('../../package.json').version.split('.').map(Number)
+const lineDiff = capture(`${diffCmd} v${releaseLine}.x master`)
+const newVersion = lineDiff.includes('SEMVER-MINOR')
+  ? `${releaseLine}.${lastMinor + 1}.0`
+  : `${releaseLine}.${lastMinor}.${lastPatch + 1}`
+
+// Checkout new branch and output new changes.
+run(`git checkout v${newVersion}-proposal || git checkout -b v${newVersion}-proposal`)
+
+// Get the hashes of the last version and the commits to add.
+const lastCommit = capture('git log -1 --pretty=%B').trim()
+const proposalDiff = capture(`${diffCmd} --format=sha --reverse v${newVersion}-proposal master`)
+  .replace(/\n/g, ' ').trim()
+
+if (proposalDiff) {
+  // We have new commits to add, so revert the version commit if it exists.
+  if (lastCommit === `v${newVersion}`) {
+    run('git reset --hard HEAD~1')
+  }
+
+  // Output new changes since last commit of the proposal branch.
+  run(`${diffCmd} v${newVersion}-proposal master`)
+
+  // Cherry pick all new commits to the proposal branch.
+  try {
+    run(`echo "${proposalDiff}" | xargs git cherry-pick`)
+  } catch (err) {
+    error('Cherry-pick failed. Resolve the conflicts and run `git cherry-pick --continue` to continue.')
+    error('When all conflicts have been resolved, run this script again.')
+    process.exit(1)
+  }
+}
+
+// Update package.json with new version.
+run(`npm version --git-tag-version=false ${newVersion}`)
+run(`git commit -uno -m v${newVersion} package.json || exit 0`)
+
+ready()
+
+// Check if current branch is already an active patch proposal branch to avoid
+// creating a new minor proposal branch if new minor commits are added to the
+// main branch during a existing patch release.
+function isActivePatch () {
+  const currentMatch = currentBranch.match(/^(\d+)\.(\d+)\.(\d+)-proposal$/)
+
+  if (currentMatch) {
+    const [major, minor, patch] = currentMatch.slice(1).map(Number)
+
+    if (major === lastMajor && minor === lastMinor && patch > lastPatch) {
+      return true
+    }
+  }
+
+  return false
+}
+
+// Output a command to the terminal and execute it.
+function run (cmd) {
+  whisper(`> ${cmd}`)
+
+  const output = execSync(cmd, {}).toString()
+
+  log(output)
+}
+
+// Run a command and capture its output to return it to the caller.
+function capture (cmd) {
+  return execSync(cmd, {}).toString()
+}
+
+// Write release notes to a file that can be copied to the GitHub release.
+function ready () {
+  const notesDir = path.join(__dirname, '..', '..', '.github', 'release_notes')
+  const notesFile = path.join(notesDir, `${newVersion}.md`)
+  const lineDiff = capture(`${diffCmd} --markdown=true v${releaseLine}.x master`)
+
+  fs.mkdirSync(notesDir, { recursive: true })
+  fs.writeFileSync(notesFile, lineDiff)
+
+  success('Release proposal is ready.')
+  success(`Changelog at .github/release_notes/${newVersion}.md`)
+
+  process.exit(0)
+}