build: fix order of JSON help generation

Previoiusly we generated the JSON help files prior to building which caused the `help` directory in the `dist` to be deleted.

Author: alan-agius4

scripts/json-help.ts

@@ -15,16 +15,27 @@ import * as path from 'path';
 import { packages } from '../lib/packages';
 import create from './create';
 
-export default async function (opts = {}, logger: logging.Logger) {
+export async function createTemporaryProject(logger: logging.Logger): Promise<string> {
   logger.info('Creating temporary project...');
   const newProjectTempRoot = await fs.mkdtemp(path.join(os.tmpdir(), 'angular-cli-create-'));
   const newProjectName = 'help-project';
   const newProjectRoot = path.join(newProjectTempRoot, newProjectName);
   await create({ _: [newProjectName] }, logger.createChild('create'), newProjectTempRoot);
 
+  return newProjectRoot;
+}
+
+export interface JsonHelpOptions {
+  temporaryProjectRoot?: string;
+}
+
+export default async function ({ temporaryProjectRoot }: JsonHelpOptions, logger: logging.Logger) {
   logger.info('Gathering JSON Help...');
+
+  const newProjectRoot = temporaryProjectRoot ?? (await createTemporaryProject(logger));
   const ngPath = path.join(newProjectRoot, 'node_modules/.bin/ng');
   const helpOutputRoot = path.join(packages['@angular/cli'].dist, 'help');
+
   await fs.mkdir(helpOutputRoot);
 
   const runNgCommandJsonHelp = async (args: string[]) => {

scripts/snapshots.ts

@@ -13,7 +13,7 @@ import * as os from 'os';
 import * as path from 'path';
 import { PackageInfo, packages } from '../lib/packages';
 import build from './build-bazel';
-import jsonHelp from './json-help';
+import jsonHelp, { createTemporaryProject } from './json-help';
 
 // Added to the README.md of the snapshot. This is markdown.
 const readmeHeaderFn = (pkg: PackageInfo) => `
@@ -164,12 +164,16 @@ export default async function (opts: SnapshotsOptions, logger: logging.Logger) {
     _exec('git', ['config', '--global', 'push.default', 'simple'], {}, logger);
   }
 
-  await jsonHelp(undefined, logger);
+  // This is needed as otherwise when we run `devkit admin create` after `bazel build` the `dist`
+  // will be overridden with the output of the legacy build.
+  const temporaryProjectRoot = await createTemporaryProject(logger);
 
   // Run build.
   logger.info('Building...');
   await build({ snapshot: true }, logger.createChild('build'));
 
+  await jsonHelp({ temporaryProjectRoot }, logger);
+
   if (!githubToken) {
     logger.info('No token given, skipping actual publishing...');