fix(schematics): warn when ng add setup runs with no features selected (#3717)

* fix(schematics): warn when ng add setup runs with no features selected

Pressing Enter without toggling any checkbox at the features prompt
silently exited with the CLI's stock "Nothing to be done." message,
giving no indication that Space selects a feature. Print a warning
explaining the checkbox controls and inviting a retry.

* refactor(schematics): derive the empty-features warning from the prompt message

The empty-features warning duplicated the checkbox prompt's message as a
second string literal, so a reworded prompt would leave the warning
pointing at text the user never sees. Export the message as a shared
constant and reference it in both places, matching the shared-constant
pattern used for the firebase-tools version message in 59c8a2f.

Author: armando-navarro

src/schematics/setup/index.ts

@@ -21,7 +21,7 @@ import {
   createFirestoreStarterFiles,
   setDefaultProjectInFirebaseRc,
 } from './firebaseConfigs';
-import { appPrompt, featuresPrompt, projectPrompt, userPrompt } from './prompts';
+import { appPrompt, featuresPrompt, featuresPromptMessage, projectPrompt, userPrompt } from './prompts';
 
 // FirebaseOptions keys — apps.sdkconfig responses include management-API extras that initializeApp() rejects.
 const firebaseOptionsKeys = [
@@ -67,7 +67,14 @@ export const ngAddSetupProject = (
 
   const features = await featuresPrompt();
 
-  if (features.length > 0) {
+  if (features.length === 0) {
+    context.logger.warn(
+      'No features were selected, so there is nothing to set up. ' +
+      `At the "${featuresPromptMessage}" prompt, use the arrow keys to move, ` +
+      'press Space to select each feature you want, then Enter to confirm. ' +
+      'Re-run ng add @angular/fire to try again.'
+    );
+  } else {
 
     const firebaseTools = await getFirebaseTools();
 

src/schematics/setup/prompts.ts

@@ -79,12 +79,14 @@ type Prompt = <K extends string, U= unknown>(questions: { name: K, source: (...a
 const autocomplete: Prompt = (questions) => inquirer.prompt(questions);
 
 
+export const featuresPromptMessage = 'What features would you like to setup?';
+
 export const featuresPrompt = async (): Promise<FEATURES[]> => {
   const { features } = await inquirer.prompt({
     type: 'checkbox',
     name: 'features',
     choices: featureOptions,
-    message: 'What features would you like to setup?',
+    message: featuresPromptMessage,
     default: [],
   }) as { features: FEATURES[] };
   return features;