feat: add support to ask customInstallTask

src/composed-store.ts

@@ -2,7 +2,7 @@ import crypto from 'node:crypto';
 import { toNamespace } from '@yeoman/namespace';
 import type { BaseGenerator, Logger } from '@yeoman/types';
 import createdLogger from 'debug';
-import type { InstallTask } from './package-manager.ts';
+import type { PackageManagerInstallTaskOptions } from './package-manager.ts';
 
 const debug = createdLogger('yeoman:environment:composed-store');
 
@@ -22,7 +22,7 @@ export class ComposedStore {
     return this.findUniqueFeature('customCommitTask');
   }
 
-  get customInstallTask(): InstallTask | undefined {
+  get customInstallTask(): PackageManagerInstallTaskOptions['customInstallTask'] | undefined {
     return this.findUniqueFeature('customInstallTask');
   }
 

src/package-manager.ts

@@ -15,7 +15,7 @@ export type PackageManagerInstallTaskOptions = {
   packageJsonLocation: string;
   adapter: InputOutputAdapter;
   nodePackageManager?: string;
-  customInstallTask?: boolean | InstallTask;
+  customInstallTask?: boolean | InstallTask | 'ask';
   skipInstall?: boolean;
 };
 
@@ -46,7 +46,11 @@ export async function packageManagerInstallTask({
    * @return {Vinyl | undefined} a Vinyl file.
    */
   function getDestinationPackageJson() {
-    return memFs.get(join(packageJsonLocation, 'package.json'));
+    const packageJsonFile = join(packageJsonLocation, 'package.json');
+
+    if (memFs.existsInMemory(packageJsonFile)) {
+      return memFs.get(packageJsonFile);
+    }
   }
 
   /**
@@ -56,14 +60,14 @@ export async function packageManagerInstallTask({
    */
   function isDestinationPackageJsonCommitted() {
     const file = getDestinationPackageJson();
-    return file.committed;
+    return file?.committed;
   }
 
   if (!getDestinationPackageJson()) {
     return false;
   }
 
-  if (customInstallTask && typeof customInstallTask !== 'function') {
+  if (customInstallTask && typeof customInstallTask !== 'function' && customInstallTask !== 'ask') {
     debug('Install disabled by customInstallTask');
     return false;
   }
@@ -102,9 +106,19 @@ Running ${packageManagerName} install for you to install the required dependenci
     return true;
   };
 
-  if (customInstallTask) {
+  if (typeof customInstallTask === 'function') {
     return customInstallTask(packageManagerName, execPackageManager);
   }
+  if (customInstallTask === 'ask') {
+    const { runInstall } = await adapter.prompt({
+      type: 'confirm',
+      name: 'runInstall',
+      message: `Do you want to run ${packageManagerName} install now?`,
+    });
+    if (!runInstall) {
+      return false;
+    }
+  }
 
   return execPackageManager();
 }

test/generator-features.js

@@ -1,12 +1,16 @@
 import assert from 'node:assert';
 import { stub } from 'sinon';
 import { after, afterEach, before, beforeEach, describe, esmocha, expect, it } from 'esmocha';
-import helpers, { getCreateEnv as getCreateEnvironment } from './helpers.js';
+import helpers, { getCreateEnv as getCreateEnvironment, result } from './helpers.js';
 import { greaterThan5 } from './generator-versions.js';
 
-const { commitSharedFsTask } = await esmocha.mock('../src/commit.ts', import('../src/commit.ts'));
-const { packageManagerInstallTask } = await esmocha.mock('../src/package-manager.ts', import('../src/package-manager.ts'));
+const commitModule = await import('../src/commit.ts');
+const { commitSharedFsTask: originalCommitSharedFsTask } = commitModule;
+const { commitSharedFsTask } = await esmocha.mock('../src/commit.ts', Promise.resolve(commitModule));
 const { execa } = await esmocha.mock('execa', import('execa'));
+const packageManagerModule = await import('../src/package-manager.ts');
+const { packageManagerInstallTask: originalPackageManagerInstallTask } = packageManagerModule;
+const { packageManagerInstallTask } = await esmocha.mock('../src/package-manager.ts', Promise.resolve(packageManagerModule));
 const { default: BasicEnvironment } = await import('../src/environment-base.ts');
 
 for (const generatorVersion of greaterThan5) {
@@ -216,6 +220,92 @@ for (const generatorVersion of greaterThan5) {
         });
       });
 
+      describe('with ask customInstallTask', () => {
+        describe('accepting to run install', () => {
+          beforeEach(async () => {
+            commitSharedFsTask.mockImplementation(originalCommitSharedFsTask);
+            packageManagerInstallTask.mockImplementation(originalPackageManagerInstallTask);
+            await helpers
+              .run('custom-install', undefined, { createEnv: getCreateEnvironment(BasicEnvironment) })
+              .withOptions({ skipInstall: false })
+              .withAnswers({ runInstall: true })
+              .withGenerators([
+                [
+                  class extends FeaturesGenerator {
+                    constructor(arguments_, options, features) {
+                      super(arguments_, options, { ...features, customInstallTask: 'ask' });
+                    }
+
+                    packageJsonTask() {
+                      this.packageJson.set({ name: 'foo' });
+                    }
+                  },
+                  { namespace: 'custom-install:app' },
+                ],
+              ]);
+          });
+
+          it('should write package.json', () => {
+            result.assertFile('package.json');
+          });
+
+          it('should call packageManagerInstallTask', () => {
+            expect(packageManagerInstallTask).toHaveBeenCalledTimes(1);
+            expect(packageManagerInstallTask).toHaveBeenCalledWith(
+              expect.objectContaining({
+                customInstallTask: 'ask',
+              }),
+            );
+          });
+
+          it('should call execa', () => {
+            expect(execa).toHaveBeenCalled();
+          });
+        });
+
+        describe('declining to run install', () => {
+          beforeEach(async () => {
+            commitSharedFsTask.mockImplementation(originalCommitSharedFsTask);
+            packageManagerInstallTask.mockImplementation(originalPackageManagerInstallTask);
+            await helpers
+              .run('custom-install', undefined, { createEnv: getCreateEnvironment(BasicEnvironment) })
+              .withOptions({ skipInstall: false })
+              .withAnswers({ runInstall: false })
+              .withGenerators([
+                [
+                  class extends FeaturesGenerator {
+                    constructor(arguments_, options, features) {
+                      super(arguments_, options, { ...features, customInstallTask: 'ask' });
+                    }
+
+                    packageJsonTask() {
+                      this.packageJson.set({ name: 'foo' });
+                    }
+                  },
+                  { namespace: 'custom-install:app' },
+                ],
+              ]);
+          });
+
+          it('should write package.json', () => {
+            result.assertFile('package.json');
+          });
+
+          it('should call packageManagerInstallTask', () => {
+            expect(packageManagerInstallTask).toHaveBeenCalledTimes(1);
+            expect(packageManagerInstallTask).toHaveBeenCalledWith(
+              expect.objectContaining({
+                customInstallTask: 'ask',
+              }),
+            );
+          });
+
+          it('should not call execa', () => {
+            expect(execa).not.toHaveBeenCalled();
+          });
+        });
+      });
+
       describe('with function customInstallTask and custom path', () => {
         let runContext;
         let customInstallTask;

test/helpers.js

@@ -9,3 +9,5 @@ export const getCreateEnv =
 export default createHelpers({
   createEnv: getCreateEnv(Environment),
 });
+
+export { result } from 'yeoman-test';

test/package-manager.js

@@ -26,7 +26,7 @@ describe('environment (package-manager)', () => {
   beforeEach(() => {
     adapter = { log: esmocha.fn() };
     execa.mockReturnValue();
-    memFs = { get: esmocha.fn() };
+    memFs = { get: esmocha.fn(), existsInMemory: esmocha.fn().mockReturnValue(true) };
     packageJsonLocation = path.join(__dirname, 'fixtures', 'package-manager', 'npm');
     whichPackageManager.mockResolvedValue('npm');
   });