build(docs-infra): compute previous version list (#39689)

Previously we hand coded the list of previous major versions
that are displayed in the left navigation.

Now these are generated from the tags in GitHub.

Closes #39688

PR Close #39689

aio/content/navigation.json

@@ -1060,35 +1060,5 @@
         }
       ]
     }
-  ],
-  "docVersions": [
-    {
-      "title": "v9",
-      "url": "https://v9.angular.io/"
-    },
-    {
-      "title": "v8",
-      "url": "https://v8.angular.io/"
-    },
-    {
-      "title": "v7",
-      "url": "https://v7.angular.io/"
-    },
-    {
-      "title": "v6",
-      "url": "https://v6.angular.io/"
-    },
-    {
-      "title": "v5",
-      "url": "https://v5.angular.io/"
-    },
-    {
-      "title": "v4",
-      "url": "https://v4.angular.io/"
-    },
-    {
-      "title": "v2",
-      "url": "https://v2.angular.io/"
-    }
   ]
 }

aio/tools/transforms/angular-base-package/index.js

@@ -8,6 +8,7 @@
 const path = require('path');
 const Package = require('dgeni').Package;
 
+const gitPackage = require('dgeni-packages/git');
 const jsdocPackage = require('dgeni-packages/jsdoc');
 const nunjucksPackage = require('dgeni-packages/nunjucks');
 const linksPackage = require('../links-package');
@@ -19,7 +20,7 @@ const postProcessPackage = require('dgeni-packages/post-process-html');
 const { PROJECT_ROOT, CONTENTS_PATH, OUTPUT_PATH, DOCS_OUTPUT_PATH, TEMPLATES_PATH, AIO_PATH, requireFolder } = require('../config');
 
 module.exports = new Package('angular-base', [
-  jsdocPackage, nunjucksPackage, linksPackage, examplesPackage, targetPackage, remarkPackage, postProcessPackage
+  gitPackage, jsdocPackage, nunjucksPackage, linksPackage, examplesPackage, targetPackage, remarkPackage, postProcessPackage
 ])
 
   // Register the processors
@@ -37,6 +38,7 @@ module.exports = new Package('angular-base', [
   .factory(require('./readers/json'))
   .factory(require('./services/copyFolder'))
   .factory(require('./services/getImageDimensions'))
+  .factory(require('./services/getPreviousMajorVersions'))
   .factory(require('./services/auto-link-filters/filterPipes'))
   .factory(require('./services/auto-link-filters/filterAmbiguousDirectiveAliases'))
   .factory(require('./services/auto-link-filters/ignoreHttpInUrls'))

aio/tools/transforms/angular-base-package/services/getPreviousMajorVersions.js

@@ -0,0 +1,54 @@
+'use strict';
+
+const child = require('child_process');
+const semver = require('semver');
+const versionMatcher = /refs\/tags\/(\d+.+)$/mg;
+
+/**
+ * Get a collection of all the previous "last major" versions sorted by semantic version.
+ *
+ * @param packageInfo injected from dgeni-packages/git
+ * @param versionInfo injected from dgeni-packages/git
+ * @returns an array of SemVer objects
+ */
+module.exports = function getPreviousMajorVersions(packageInfo, versionInfo) {
+  return () => {
+    // always use the remote tags as the local clone might not contain all commits when cloned with
+    // `git clone --depth=...`
+    const repoUrl = packageInfo.repository.url;
+    const tagResults = child.spawnSync('git', ['ls-remote', '--tags', repoUrl], {encoding: 'utf8'});
+
+    if (tagResults.status !== 0) {
+      return [];
+    }
+
+    const majorVersions = {};
+    tagResults.stdout.replace(versionMatcher, (_, tag) => {
+      const version = semver.parse(tag);
+
+      // Not interested in tags that do not match semver format.
+      if (version === null) {
+        return;
+      }
+
+      // Not interested in pre-release versions.
+      if (version.prerelease !== null && version.prerelease.length > 0) {
+        return;
+      }
+
+      // Only interested in versions that are earlier than the current major.
+      if (version.major >= versionInfo.currentVersion.major) {
+        return;
+      }
+
+      const currentMajor = majorVersions[version.major];
+      if (currentMajor === undefined || semver.compare(version, currentMajor) === 1) {
+        // This version is newer than the currently captured version for this major.
+        majorVersions[version.major] = version;
+      }
+    });
+
+    // Sort them in descending order
+    return semver.sort(Object.values(majorVersions)).reverse();
+  };
+};

aio/tools/transforms/angular-base-package/services/getPreviousMajorVersions.spec.js

@@ -0,0 +1,63 @@
+const child = require('child_process');
+const Dgeni = require('dgeni');
+const semver = require('semver');
+
+const basePackage = require('../index');
+
+describe('getPreviousMajorVersions', () => {
+  let getPreviousMajorVersions;
+
+  beforeEach(() => {
+    const mockPackage = new Dgeni.Package('mock-package', [basePackage])
+                            .factory('versionInfo', mockVersionInfo)
+                            .factory('packageInfo', mockPackageInfo);
+    const dgeni = new Dgeni([mockPackage]);
+    const injector = dgeni.configureInjector();
+    getPreviousMajorVersions = injector.get('getPreviousMajorVersions');
+  });
+
+  it('should spawn a child process to git', () => {
+    spyOn(child, 'spawnSync').and.returnValue({status: 0, stdout: ''});
+    getPreviousMajorVersions();
+    expect(child.spawnSync).toHaveBeenCalledWith('git', ['ls-remote', '--tags', 'SOME_GIT_URL'], {
+      encoding: 'utf8'
+    });
+  });
+
+  it('should return an empty list for a failed git command', () => {
+    spyOn(child, 'spawnSync').and.returnValue({status: 1});
+    expect(getPreviousMajorVersions()).toEqual([]);
+  });
+
+  it('should return an empty list for no tags', () => {
+    spyOn(child, 'spawnSync').and.returnValue({status: 0, stdout: ''});
+    expect(getPreviousMajorVersions()).toEqual([]);
+  });
+
+  it('should return an array of latest major versions with major greater than current', () => {
+    spyOn(child, 'spawnSync').and.returnValue({
+      status: 0,
+      stdout: `
+    refs/pull/655
+    refs/tags/some-tag
+    refs/tags/3.8.1
+    refs/tags/4.2.9
+    refs/tags/4.2.10
+    refs/tags/5.6.1
+    refs/tags/6.1.1
+    `
+    });
+    expect(getPreviousMajorVersions()).toEqual([
+      semver('4.2.10'),
+      semver('3.8.1'),
+    ]);
+  });
+});
+
+function mockVersionInfo() {
+  return {currentVersion: new semver('5.1.0')};
+}
+
+function mockPackageInfo() {
+  return {repository: {url: 'SOME_GIT_URL'}};
+}

aio/tools/transforms/angular.io-package/processors/processNavigationMap.js

@@ -1,15 +1,14 @@
-module.exports = function processNavigationMap(versionInfo, log) {
+module.exports = function processNavigationMap(versionInfo, getPreviousMajorVersions, log) {
   return {
     $runAfter: ['paths-computed'],
     $runBefore: ['rendering-docs'],
     $process: function(docs) {
-
       const navigationDoc = docs.find(doc => doc.docType === 'navigation-json');
 
       if (!navigationDoc) {
         throw new Error(
-          'Missing navigation map document (docType="navigation-json").' +
-          'Did you forget to add it to the readFileProcessor?');
+            'Missing navigation map document (docType="navigation-json").' +
+            'Did you forget to add it to the readFileProcessor?');
       }
 
       // Verify that all the navigation paths are to valid docs
@@ -24,6 +23,9 @@ module.exports = function processNavigationMap(versionInfo, log) {
         throw new Error('processNavigationMap failed');
       }
 
+      navigationDoc.data['docVersions'] = getPreviousMajorVersions().map(
+          v => ({title: `v${v.major}`, url: `https://v${v.major}.angular.io/`}));
+
       // Add in the version data in a "secret" field to be extracted in the docs app
       navigationDoc.data['__versionInfo'] = versionInfo.currentVersion;
     }
@@ -32,13 +34,13 @@ module.exports = function processNavigationMap(versionInfo, log) {
 
 function walk(node, map, path) {
   let errors = [];
-  for(const key in node) {
+  for (const key in node) {
     const child = node[key];
-    if (child !== null) { // null is allowed
+    if (child !== null) {  // null is allowed
       if (key === 'url') {
-        const url = child.replace(/#.*$/, ''); // strip hash
+        const url = child.replace(/#.*$/, '');  // strip hash
         if (isRelative(url) && !map[url]) {
-          errors.push({ path: path.join('.'), url });
+          errors.push({path: path.join('.'), url});
         }
       } else if (typeof child !== 'string') {
         errors = errors.concat(walk(child, map, path.concat([key])));