fix(@angular/cli): improve error message for Windows autocompletion use cases

packages/angular/cli/src/utilities/completion.ts

@@ -193,7 +193,9 @@ export async function initializeAutocomplete(): Promise<string> {
   if (!shell) {
     throw new Error(
       '`$SHELL` environment variable not set. Angular CLI autocompletion only supports Bash or' +
-        ' Zsh.',
+        " Zsh. If you're on Windows, Cmd and Powershell don't support command autocompletion," +
+        ' but Git Bash or Windows Subsystem for Linux should work, so please try again in one of' +
+        ' those environments.',
     );
   }
   const home = env['HOME'];
@@ -234,7 +236,7 @@ export async function initializeAutocomplete(): Promise<string> {
   return rcFile;
 }
 
-/** Returns an ordered list of possibile candidates of RC files used by the given shell. */
+/** Returns an ordered list of possible candidates of RC files used by the given shell. */
 function getShellRunCommandCandidates(shell: string, home: string): string[] | undefined {
   if (shell.toLowerCase().includes('bash')) {
     return ['.bashrc', '.bash_profile', '.profile'].map((file) => path.join(home, file));

tests/legacy-cli/e2e/tests/misc/completion-prompt.ts

@@ -19,6 +19,13 @@ const DEFAULT_ENV = Object.freeze({
 });
 
 export default async function () {
+  // Windows Cmd and Powershell do not support autocompletion. Run a different set of tests to
+  // confirm autocompletion skips the prompt appropriately.
+  if (process.platform === 'win32') {
+    await windowsTests();
+    return;
+  }
+
   // Sets up autocompletion after user accepts a prompt from any command.
   await mockHome(async (home) => {
     const bashrc = path.join(home, '.bashrc');
@@ -42,7 +49,7 @@ export default async function () {
     const bashrcContents = await fs.readFile(bashrc, 'utf-8');
     if (!bashrcContents.includes('source <(ng completion script)')) {
       throw new Error(
-        'Autocompletion was *not* added to `~/.bashrc` after accepting the setup' + ' prompt.',
+        'Autocompletion was *not* added to `~/.bashrc` after accepting the setup prompt.',
       );
     }
 
@@ -74,13 +81,13 @@ export default async function () {
     const bashrcContents = await fs.readFile(bashrc, 'utf-8');
     if (bashrcContents.includes('ng completion')) {
       throw new Error(
-        'Autocompletion was incorrectly added to `~/.bashrc` after refusing the setup' + ' prompt.',
+        'Autocompletion was incorrectly added to `~/.bashrc` after refusing the setup prompt.',
       );
     }
 
     if (stdout.includes('Appended `source <(ng completion script)`')) {
       throw new Error(
-        'CLI printed that it successfully set up autocompletion when it actually' + " didn't.",
+        "CLI printed that it successfully set up autocompletion when it actually didn't.",
       );
     }
 
@@ -363,6 +370,23 @@ source <(ng completion script)
   });
 }
 
+async function windowsTests(): Promise<void> {
+  // Should *not* prompt on Windows, autocompletion isn't supported.
+  await mockHome(async (home) => {
+    const bashrc = path.join(home, '.bashrc');
+    await fs.writeFile(bashrc, `# Other content...`);
+
+    const { stdout } = await execWithEnv('ng', ['version'], { ...env });
+
+    if (AUTOCOMPLETION_PROMPT.test(stdout)) {
+      throw new Error(
+        'Execution prompted to set up autocompletion on Windows despite not actually being' +
+          ' supported.',
+      );
+    }
+  });
+}
+
 async function mockHome(cb: (home: string) => Promise<void>): Promise<void> {
   const tempHome = await fs.mkdtemp(path.join(os.tmpdir(), 'angular-cli-e2e-home-'));
 

tests/legacy-cli/e2e/tests/misc/completion.ts

@@ -4,6 +4,14 @@ import * as path from 'path';
 import { execAndCaptureError, execAndWaitForOutputToMatch } from '../../utils/process';
 
 export default async function () {
+  // Windows Cmd and Powershell do not support autocompletion. Run a different set of tests to
+  // confirm autocompletion fails gracefully.
+  if (process.platform === 'win32') {
+    await windowsTests();
+
+    return;
+  }
+
   // Generates new `.bashrc` file.
   await mockHome(async (home) => {
     await execAndWaitForOutputToMatch(
@@ -302,25 +310,37 @@ source <(ng completion script)
   }
 
   // Fails for no `$SHELL`.
-  {
+  await mockHome(async (home) => {
     const err = await execAndCaptureError('ng', ['completion'], {
       ...process.env,
       SHELL: undefined,
+      HOME: home,
     });
     if (!err.message.includes('`$SHELL` environment variable not set.')) {
       throw new Error(`Expected unset \`$SHELL\` error message, but got:\n\n${err.message}`);
     }
-  }
+  });
 
   // Fails for unknown `$SHELL`.
-  {
+  await mockHome(async (home) => {
     const err = await execAndCaptureError('ng', ['completion'], {
       ...process.env,
       SHELL: '/usr/bin/unknown',
+      HOME: home,
     });
     if (!err.message.includes('Unknown `$SHELL` environment variable')) {
       throw new Error(`Expected unknown \`$SHELL\` error message, but got:\n\n${err.message}`);
     }
+  });
+}
+
+async function windowsTests(): Promise<void> {
+  // Should fail with a clear error message.
+  const err = await execAndCaptureError('ng', ['completion']);
+  if (!err.message.includes("Cmd and Powershell don't support command autocompletion")) {
+    throw new Error(
+      `Expected Windows autocompletion to fail with custom error, but got:\n\n${err.message}`,
+    );
   }
 }