[ios, build] Populate GitHub releases with templated notes

Replicates our existing release notes format as an EJS template and Node JS script, then uploads the formatted notes during the deployment process.

package.json

@@ -29,6 +29,7 @@
     "pixelmatch": "^4.0.2",
     "pngjs": "^3.0.0",
     "request": "^2.72.0",
+    "semver": "^5.5.0",
     "tape": "^4.5.1"
   },
   "engines": {

platform/ios/scripts/deploy-packages.sh

@@ -102,10 +102,12 @@ if [[ "${GITHUB_RELEASE}" == true ]]; then
     if [[ $( echo ${PUBLISH_VERSION} | awk '/[0-9]-/' ) ]]; then
         PUBLISH_PRE_FLAG='--pre-release'
     fi
+    RELEASE_NOTES=$( ./platform/ios/scripts/release-notes.js )
     github-release release \
         --tag "ios-v${PUBLISH_VERSION}" \
         --name "ios-v${PUBLISH_VERSION}" \
-        --draft ${PUBLISH_PRE_FLAG}
+        --draft ${PUBLISH_PRE_FLAG} \
+        --description "${RELEASE_NOTES}"
 fi
 
 buildPackageStyle "ipackage" "symbols"

platform/ios/scripts/release-notes.js

@@ -0,0 +1,37 @@
+#!/usr/bin/env node
+
+const fs = require('fs');
+const ejs = require('ejs');
+const _ = require('lodash');
+const semver = require('semver');
+
+const changelog = fs.readFileSync('platform/ios/CHANGELOG.md', 'utf8');
+
+// This regular expression parses the changelog for individual releases:
+//  - Matches lines starting with "## ".
+//  - Groups the version number.
+//  - Skips the (optional) release date.
+//  - Groups the changelog content.
+//  - Ends when another "## " is found.
+const regex = /^## (\d+\.\d+\.\d+).*?\n(.+?)(?=\n^## )/gms;
+
+let releases = [];
+while (match = regex.exec(changelog)) {
+    releases.push({
+        'version': match[1],
+        'changelog': match[2].trim(),
+    });
+}
+
+const currentRelease = releases[0];
+
+const versions = _.map(releases, 'version');
+const previousVersion = semver.maxSatisfying(versions, "<" + currentRelease.version);
+
+const releaseNotes = ejs.render(fs.readFileSync('platform/ios/scripts/release-notes.md.ejs', 'utf8'), {
+    'currentVersion': currentRelease.version,
+    'previousVersion': previousVersion,
+    'changelog': currentRelease.changelog,
+});
+
+process.stdout.write(releaseNotes);

platform/ios/scripts/release-notes.md.ejs

@@ -0,0 +1,10 @@
+<%
+  const CURRENTVERSION = locals.currentVersion;
+  const PREVIOUSVERSION = locals.previousVersion;
+  const CHANGELOG = locals.changelog;
+-%>
+[Changes](https://github.com/mapbox/mapbox-gl-native/compare/ios-v<%-PREVIOUSVERSION%>...ios-v<%-CURRENTVERSION%>) since [Mapbox Maps SDK for iOS v<%-PREVIOUSVERSION%>](https://github.com/mapbox/mapbox-gl-native/releases/tag/ios-v<%-PREVIOUSVERSION%>):
+
+<%-CHANGELOG%>
+
+Documentation is [available online](https://www.mapbox.com/ios-sdk/api/<%-CURRENTVERSION%>/) or as part of the download.