From 772e39b710a6827632162d44e78aebddcfd113bc Mon Sep 17 00:00:00 2001
From: Laurent Cozic <laurent@cozic.net>
Date: Sun, 8 Sep 2019 17:54:41 +0100
Subject: [PATCH] Tools: Improved git-changelog so that it is less error prone

---
 Tools/git-changelog.js | 41 +++++++++++++++++++++++++++++++++++++----
 Tools/release-cli.js   | 12 +-----------
 2 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/Tools/git-changelog.js b/Tools/git-changelog.js
index 295a2c2314..7d6f79dae6 100644
--- a/Tools/git-changelog.js
+++ b/Tools/git-changelog.js
@@ -175,14 +175,47 @@ function capitalizeFirstLetter(string) {
 	return string.charAt(0).toUpperCase() + string.slice(1);
 }
 
+function decreaseTagVersion(tag) {
+	const s = tag.split('.');
+	let num = Number(s.pop());
+	num--;
+	if (num < 0) throw new Error('Cannot decrease tag version: ' + tag);
+	s.push('' + num);
+	return s.join('.');
+}
+
+// This function finds the first relevant tag starting from the given tag.
+// The first "relevant tag" is the one that exists, and from which there are changes.
+async function findFirstRelevantTag(baseTag) {
+	let tag = decreaseTagVersion(baseTag);
+	while (true) {
+		try {
+			const logs = await gitLog(tag);
+			if (logs.length) return tag;
+		} catch (error) {
+			if (error.message.indexOf('unknown revision') >= 0) {
+				// We skip the error - it means this particular tag has never been created
+			} else {
+				throw error;
+			}
+		}
+
+		tag = decreaseTagVersion(tag);
+	}
+}
+
 async function main() {
 	const argv = require('yargs').argv;
-	if (!argv._.length) throw new Error('Tag name must be specified');
+	if (!argv._.length) throw new Error('Tag name must be specified. Provide the tag of the new version and git-changelog will walk backward to find the changes to the previous relevant tag.');
 
-	const sinceTagName = argv._[0];
-	const platform = platformFromTag(sinceTagName);
+	const fromTagName = argv._[0];
+
+	const platform = platformFromTag(fromTagName);
+
+	const toTagName = await findFirstRelevantTag(fromTagName);
+
+	const logsSinceTags = await gitLog(toTagName);
 
-	const logsSinceTags = await gitLog(sinceTagName);
 	const filteredLogs = filterLogs(logsSinceTags, platform);
 
 	let changelog = createChangeLog(filteredLogs);
diff --git a/Tools/release-cli.js b/Tools/release-cli.js
index 39cd71f8ff..c6eb5f8cde 100644
--- a/Tools/release-cli.js
+++ b/Tools/release-cli.js
@@ -50,18 +50,8 @@ async function insertChangelog(tag, changelog) {
 // Start with node Tools/release-cli.js --changelog-from cli-v1.0.126
 // to specify from where the changelog should be created
 async function main() {
-	const argv = require('yargs').argv;
-
 	process.chdir(appDir);
 
-	const packageJson = await fs.readFile('package.json', 'UTF-8');
-	const packageConf = JSON.parse(packageJson);
-
-	const previousVersion = 'v' + packageConf.version;
-	let changelogFrom = 'cli-' + previousVersion;
-
-	if (argv.changelogFrom) changelogFrom = argv.changelogFrom;
-
 	const newVersion = await execCommand('npm version patch');
 	console.info('Building ' + newVersion + '...');
 	const newTag = 'cli-' + newVersion;
@@ -75,7 +65,7 @@ async function main() {
 
 	await execCommand('npm publish');
 
-	const changelog = await execCommand('node ' + rootDir + '/Tools/git-changelog ' + changelogFrom);
+	const changelog = await execCommand('node ' + rootDir + '/Tools/git-changelog ' + newTag);
 
 	const newChangelog = await insertChangelog(newTag, changelog);