From cb930d006a112028b9c8b71b65d207e40adb84cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Leosvel=20P=C3=A9rez=20Espinosa?=
 <leosvel.perez.espinosa@gmail.com>
Date: Tue, 3 Jun 2025 12:55:29 +0200
Subject: [PATCH] fix(core): ensure nx init implementation for angular
 correctly resolves `@angular/core` (#31430)

## Current Behavior

When running `nx init` in an Angular CLI repo located in a directory
that has an ancestor directory with an Nx installation, it silently
exits when trying to determine the compatibility of the Angular version.
The migration is not performed, and no feedback is given to the user.
This happens because the current implementation will determine that
ancestor directory (outside the workspace root) as the workspace root
(when starting the migration, there's no `nx` in the repo).

## Expected Behavior

Running `nx init` should work correctly, and proper feedback should be
printed to the user if it can't determine the compatibility of the
Angular version. It should correctly resolve the `@angular/core` package
from the Angular CLI workspace root.

## Related Issue(s)

Fixes #31291
---
 .../angular/legacy-angular-versions.ts        | 25 ++++++++++++++++---
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/packages/nx/src/command-line/init/implementation/angular/legacy-angular-versions.ts b/packages/nx/src/command-line/init/implementation/angular/legacy-angular-versions.ts
index 40fefed68c..4d332430ce 100644
--- a/packages/nx/src/command-line/init/implementation/angular/legacy-angular-versions.ts
+++ b/packages/nx/src/command-line/init/implementation/angular/legacy-angular-versions.ts
@@ -2,6 +2,7 @@ import { execSync } from 'child_process';
 import { join } from 'path';
 import { gte, major } from 'semver';
 import { readJsonFile, writeJsonFile } from '../../../../utils/fileutils';
+import { getNxRequirePaths } from '../../../../utils/installation-directory';
 import { sortObjectByKeys } from '../../../../utils/object-sort';
 import { output } from '../../../../utils/output';
 import { readModulePackageJson } from '../../../../utils/package-json';
@@ -11,9 +12,9 @@ import {
   resolvePackageVersionUsingInstallation,
   resolvePackageVersionUsingRegistry,
 } from '../../../../utils/package-manager';
+import { connectExistingRepoToNxCloudPrompt } from '../../../connect/connect-to-nx-cloud';
 import { initCloud } from '../utils';
 import type { Options } from './types';
-import { connectExistingRepoToNxCloudPrompt } from '../../../connect/connect-to-nx-cloud';
 
 // map of Angular major versions to Nx versions to use for legacy `nx init` migrations,
 // key is major Angular version and value is Nx version to use
@@ -35,9 +36,25 @@ export async function getLegacyMigrationFunctionIfApplicable(
   repoRoot: string,
   options: Options
 ): Promise<() => Promise<void> | null> {
-  const angularVersion =
-    readModulePackageJson('@angular/core').packageJson.version;
-  const majorAngularVersion = major(angularVersion);
+  let majorAngularVersion: number;
+  try {
+    const angularVersion = readModulePackageJson('@angular/core', [
+      repoRoot,
+      ...getNxRequirePaths(),
+    ]).packageJson.version;
+    majorAngularVersion = major(angularVersion);
+  } catch {
+    output.error({
+      title: 'Could not determine the existing Angular version',
+      bodyLines: [
+        'Please ensure "@angular/core" is installed in the workspace and you are running this command from the root of the workspace.',
+      ],
+    });
+    // errors are caught in the initHandler and not logged to the user, so we
+    // log it first and then throw to ensure it is logged to the user
+    throw new Error('Could not determine the existing Angular version');
+  }
+
   if (majorAngularVersion >= minMajorAngularVersionSupported) {
     // non-legacy
     return null;