build: move changelog script to gulp task (#5472)

* Moves the changelog script to a gulp task that includes better instructions and error reporting.

package.json

@@ -59,7 +59,6 @@
     "axe-core": "^2.3.1",
     "axe-webdriverjs": "^1.1.1",
     "chalk": "^1.1.3",
-    "conventional-changelog": "^1.1.3",
     "dgeni": "^0.4.7",
     "dgeni-packages": "^0.19.1",
     "firebase": "^4.0.0",
@@ -73,6 +72,7 @@
     "gulp-clean-css": "^3.3.1",
     "gulp-cli": "^1.3.0",
     "gulp-connect": "^5.0.0",
+    "gulp-conventional-changelog": "^1.1.3",
     "gulp-dom": "^0.9.17",
     "gulp-flatten": "^0.3.1",
     "gulp-highlight-files": "^0.0.4",
@@ -98,7 +98,6 @@
     "karma-sourcemap-loader": "^0.3.7",
     "madge": "^1.6.0",
     "magic-string": "^0.21.3",
-    "merge2": "^1.0.3",
     "minimatch": "^3.0.4",
     "minimist": "^1.2.0",
     "node-sass": "^4.5.3",

scripts/release/changelog.js

@@ -1,78 +0,0 @@
-#!/usr/bin/env node
-
-'use strict';
-
-/*
- * Creates a conventional changelog from the current git repository / metadata.
- */
-
-const fs = require('fs');
-const merge2 = require('merge2');
-const changelog = require('conventional-changelog');
-const spawnSync = require('child_process').spawnSync;
-const npmVersion = require('../../package.json').version;
-
-/**
- * When the command line argument `--force` is provided, then the full changelog will created and overwritten.
- * By default, it will only create the changelog from the latest tag to head and prepends it to the changelog.
- */
-const isForce = process.argv.indexOf('--force') !== -1;
-const previousChangelog = fs.createReadStream('CHANGELOG.md');
-const gitTags = getAvailableTags();
-
-// Whether the npm version is later than the most recent tag.
-const isNpmLatest = npmVersion !== gitTags[0];
-// When the npm version is the latest, use the npm version, otherwise use the latest tag.
-const currentTag = isNpmLatest ? npmVersion : gitTags[0];
-// When the npm version is the latest use the most recent tag. Otherwise use the previous tag.
-const previousTag = isNpmLatest ? gitTags[0] : gitTags[1];
-
-if (!isForce) {
-  previousChangelog.on('error', function(err) {
-    console.error('An error occurred, while reading the previous changelog file.\n' +
-      'If there is changelog file, you should create an empty file or use the `--force` flag.\n' + err);
-
-    process.exit(1);
-  });
-}
-
-const config = {
-  preset: 'angular',
-  releaseCount: isForce ? 0 : 1
-};
-
-const context = {
-  currentTag: currentTag,
-  previousTag: previousTag
-};
-
-let stream = changelog(config, context).on('error', function(err) {
-  console.error('An error occurred while generating the changelog: ' + err);
-});
-
-if (!isForce) {
-  // Append the previous changelog to the new generated one.
-  stream = merge2(stream, previousChangelog);
-} else {
-  stream.pipe(getOutputStream())
-}
-
-// When we are pre-pending the new changelog, then we need to wait for the input stream to be ending,
-// otherwise we can't write into the same destination.
-if (!isForce) {
-  previousChangelog.on('end', function() {
-    stream.pipe(getOutputStream());
-  });
-}
-
-function getOutputStream() {
-  return fs.createWriteStream('CHANGELOG.md');
-}
-
-/**
- * Resolves available tags over all branches from the repository metadata.
- * @returns {Array.<String>} Array of available tags.
- */
-function getAvailableTags() {
-  return spawnSync('git', ['tag']).stdout.toString().trim().split('\n').reverse();
-}

tools/gulp/gulpfile.ts

@@ -22,3 +22,4 @@ import './tasks/coverage';
 import './tasks/material-release';
 import './tasks/universal';
 import './tasks/validate-release';
+import './tasks/changelog';

tools/gulp/tasks/changelog.ts

@@ -0,0 +1,60 @@
+import {task, src, dest} from 'gulp';
+import {buildConfig} from 'material2-build-tools';
+import {join} from 'path';
+import {yellow, red} from 'chalk';
+
+// This imports lack of type definitions.
+const gulpChangelog = require('gulp-conventional-changelog');
+const gitSemverTags = require('git-semver-tags');
+
+/** Path to the changelog markdown file of the project. */
+const changelogFile = join(buildConfig.projectDir, 'CHANGELOG.md');
+
+/** Default changelog options that are passed to gulp-conventional-changelog. */
+const changelogOptions = { preset: 'angular' };
+
+/** Task that generates a new changelog section from the latest tag to HEAD. */
+task('changelog', async () => {
+  // Show the instructions for the changelog generation.
+  showChangelogInstructions();
+
+  // Cancel the generation when the latest tag is the same as the version from the "package.json".
+  if (await getLatestSemverTag() === buildConfig.projectVersion) {
+    console.error(red('Warning: Changelog won\'t change because the "package.json" version is ' +
+        'equal to the latest Git tag.\n'));
+    return;
+  }
+
+  return src(changelogFile)
+    .pipe(gulpChangelog(changelogOptions))
+    .pipe(dest('./'));
+});
+
+/** Task that re-generates the full changelog. */
+task('changelog:full', () => {
+  return src(changelogFile)
+    .pipe(gulpChangelog({ ...changelogOptions, releaseCount: 0 }))
+    .pipe(dest('./'));
+});
+
+/** Prints a message that gives instructions about generating a changelog section. */
+function showChangelogInstructions() {
+  console.info(`
+    ${yellow('Changelog Instructions')}
+
+    When running this command, the changelog from the latest tag to HEAD will be generated.
+    The name of the new changelog section will be taken from the "package.json" version.
+
+    The recommended steps when creating a new changelog section:
+      1. Bump the version in the "package.json"
+      2. Run the changelog gulp task
+      3. Tweak the changelog manually.
+  `);
+}
+
+/** Returns the latest Semver Tag from the project Git repository */
+function getLatestSemverTag(): Promise<string> {
+  return new Promise((resolve, reject) => {
+    return gitSemverTags((err: Error, tags: string[]) => err ? reject(err) : resolve(tags[0]));
+  });
+}