scripts: Add @iarna's changelog generator tool

PR-URL: https://github.com/npm/npm/pull/11077
Credit: @iarna
Reviewed-By: ¯\_(ツ)_/¯
Reviewed-By: @othiym23

2 files changed, 99 insertions, 0 deletions

diff --git a/scripts/changelog.js b/scripts/changelog.js
new file mode 100644
index 000000000..ae3ba5a6a
--- /dev/null
+++ b/scripts/changelog.js
@@ -0,0 +1,92 @@
+'use strict'
+/*
+Usage:
+
+node scripts/changelog.js [comittish]
+
+Generates changelog entries in our format as best as its able based on
+commits starting at comittish, or if that's not passed, master.
+
+Ordinarily this is run via the gen-changelog shell script, which appends
+the result to the changelog.
+
+*/
+const execSync = require('child_process').execSync
+const branch = process.argv[2] || 'master'
+const log = execSync(`git log --pretty='format:%h %H%d %s (%aN)%n%b%n---%n' ${branch}...`).toString().split(/\n/)
+const authormap = {
+  'Rebecca Turner': 'iarna',
+  'Forrest L Norvell': 'othiym23',
+  'Kyle Mitchell': 'kemitchell',
+  'Chris Rebert': 'cvrebert',
+  'Kat Marchán': 'zkat'
+}
+
+main()
+
+function print_commit (c) {
+  let m
+  console.log(`* [\`${c.shortid}\`](https://github.com/npm/npm/commit/${c.fullid})`)
+  if (c.fixes) {
+    console.log(`  [#${c.fixes}](https://github.com/npm/npm/issues/${c.fixes})`)
+  } else if (c.prurl && (m = c.prurl.match(/https:\/\/github.com\/([^/]+\/[^/]+)\/pull\/(\d+)/))) {
+    let repo = m[1]
+    let prid = m[2]
+    if (repo !== 'npm/npm') {
+      console.log(`  [${repo}#${prid}](${c.prurl})`)
+    } else {
+      console.log(`  [#${prid}](${c.prurl})`)
+    }
+  } else if (c.prurl) {
+    console.log(`  [#](${c.prurl})`)
+  }
+  let msg = c.message
+    .replace(/^\s+/mg, '')
+    .replace(/^[-a-z]+: /, '')
+    .replace(/^/mg, '  ')
+    .replace(/\n$/, '')
+  // backtickify package@version
+    .replace(/^(\s*[^@\s]+@\d+[.]\d+[.]\d+)(\s*\S)/g, '$1:$2')
+    .replace(/\b([^@\s]+@\d+[.]\d+[.]\d+)\b/g, '`$1`')
+  // linkify commitids
+    .replace(/\b([a-f0-9]{7,8})\b/g, '[`$1`](https://github.com/npm/npm/commit/$1)')
+    .replace(/\b#(\d+)\b/g, '[#$1](https://github.com/npm/npm/issues/$1)')
+  console.log(msg)
+  if (c.credit) {
+    console.log(`  ([@${c.credit}](https://github.com/${c.credit}))`)
+  } else {
+    console.log(`  ([@${c.author}](https://github.com/${c.author}))`)
+  }
+}
+
+function main () {
+  let commit
+  log.forEach(function (line) {
+    let m
+    /*eslint no-cond-assign:0*/
+    if (/^---$/.test(line)) {
+      print_commit(commit)
+    } else if (m = line.match(/^([a-f0-9]{7}) ([a-f0-9]+) (?:[(]([^)]+)[)] )?(.*?) [(](.*?)[)]/)) {
+      commit = {
+        shortid: m[1],
+        fullid: m[2],
+        branch: m[3],
+        message: m[4],
+        author: authormap[m[5]] || m[5],
+        prurl: null,
+        fixes: null,
+        credit: null
+      }
+    } else if (m = line.match(/^PR-URL: (.*)/)) {
+      commit.prurl = m[1]
+    } else if (m = line.match(/^Credit: @(.*)/)) {
+      commit.credit = m[1]
+    } else if (m = line.match(/^Fixes: #(.*)/)) {
+      commit.fixes = m[1]
+    } else if (m = line.match(/^Reviewed-By: @(.*)/)) {
+      commit.reviewed = m[1]
+    } else if (/\S/.test(line)) {
+      commit.message += `\n${line}`
+    }
+  })
+}
diff --git a/scripts/gen-changelog b/scripts/gen-changelog
new file mode 100755
index 000000000..efec4d54e
--- /dev/null
+++ b/scripts/gen-changelog
@@ -0,0 +1,7 @@
+#!/bin/sh
+# Usage: gen-changelog [comittish]
+# Reads all the commits since comittish and produces changelog entries in
+# our style as best as it can, appendning them to CHANGELOG.md.  If it
+# encounters a git error it won't modify CHANGELOG.md
+# @iarna uses this as the first step in producing changelogs for a release.
+(node $(npm prefix)/scripts/changelog.js "$@"; cat CHANGELOG.md) > new.md && mv new.md CHANGELOG.md