fix(@angular/cli): support silent package installs with Yarn 2+

Yarn 2 and higher no longer support the `--silent` flag.
The Angular CLI will now spawn package managers with the stdout ignored when silent
mode is needed and only show stderr when the process exits unsuccessfully. This
provides the necessary functionality for the CLI without relying on package manager
options.

Author: clydin

packages/angular/cli/src/utilities/package-manager.ts

@@ -18,7 +18,6 @@ import { memoize } from './memoize';
 import { Spinner } from './spinner';
 
 interface PackageManagerOptions {
-  silent: string;
   saveDev: string;
   install: string;
   installAll?: string;
@@ -79,28 +78,24 @@ export class PackageManagerUtils {
     cwd?: string,
   ): Promise<boolean> {
     const packageManagerArgs = this.getArguments();
-    const installArgs: string[] = [
-      packageManagerArgs.install,
-      packageName,
-      packageManagerArgs.silent,
-    ];
+    const installArgs: string[] = [packageManagerArgs.install, packageName];
 
     if (save === 'devDependencies') {
       installArgs.push(packageManagerArgs.saveDev);
     }
 
-    return this.run([...installArgs, ...extraArgs], cwd);
+    return this.run([...installArgs, ...extraArgs], { cwd, silent: true });
   }
 
   /** Install all packages. */
   async installAll(extraArgs: string[] = [], cwd?: string): Promise<boolean> {
     const packageManagerArgs = this.getArguments();
-    const installArgs: string[] = [packageManagerArgs.silent];
+    const installArgs: string[] = [];
     if (packageManagerArgs.installAll) {
       installArgs.push(packageManagerArgs.installAll);
     }
 
-    return this.run([...installArgs, ...extraArgs], cwd);
+    return this.run([...installArgs, ...extraArgs], { cwd, silent: true });
   }
 
   /** Install a single package temporary. */
@@ -160,15 +155,13 @@ export class PackageManagerUtils {
     switch (this.name) {
       case PackageManager.Yarn:
         return {
-          silent: '--silent',
           saveDev: '--dev',
           install: 'add',
           prefix: '--modules-folder',
           noLockfile: '--no-lockfile',
         };
       case PackageManager.Pnpm:
         return {
-          silent: '--silent',
           saveDev: '--save-dev',
           install: 'add',
           installAll: 'install',
@@ -177,7 +170,6 @@ export class PackageManagerUtils {
         };
       default:
         return {
-          silent: '--quiet',
           saveDev: '--save-dev',
           install: 'install',
           installAll: 'install',
@@ -187,15 +179,21 @@ export class PackageManagerUtils {
     }
   }
 
-  private async run(args: string[], cwd = process.cwd()): Promise<boolean> {
+  private async run(
+    args: string[],
+    options: { cwd?: string; silent?: boolean } = {},
+  ): Promise<boolean> {
+    const { cwd = process.cwd(), silent = false } = options;
+
     const spinner = new Spinner();
     spinner.start('Installing packages...');
 
     return new Promise((resolve) => {
       const bufferedOutput: { stream: NodeJS.WriteStream; data: Buffer }[] = [];
 
       const childProcess = spawn(this.name, args, {
-        stdio: 'pipe',
+        // Always pipe stderr to allow for failures to be reported
+        stdio: silent ? ['ignore', 'ignore', 'pipe'] : 'pipe',
         shell: true,
         cwd,
       }).on('close', (code: number) => {