feat: add a warning that shows if user uses node -v <20 #2930 (#3371)

Co-authored-by: Jacob Richman <jacob314@gmail.com>

packages/cli/src/utils/userStartupWarnings.test.ts

@@ -8,6 +8,7 @@ import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { getUserStartupWarnings } from './userStartupWarnings.js';
 import * as os from 'os';
 import fs from 'fs/promises';
+import semver from 'semver';
 
 vi.mock('os', () => ({
   default: { homedir: vi.fn() },
@@ -18,6 +19,13 @@ vi.mock('fs/promises', () => ({
   default: { realpath: vi.fn() },
 }));
 
+vi.mock('semver', () => ({
+  default: {
+    major: vi.fn(),
+  },
+  major: vi.fn(),
+}));
+
 describe('getUserStartupWarnings', () => {
   const homeDir = '/home/user';
 
@@ -66,6 +74,44 @@ describe('getUserStartupWarnings', () => {
     });
   });
 
+  function setNodeVersionMajor(majorVersion: number) {
+    vi.mocked(semver.major).mockReturnValue(majorVersion);
+  }
+
+  describe('node version check', () => {
+    afterEach(() => {
+      setNodeVersionMajor(20);
+    });
+
+    it('should return a warning if Node.js version is less than minMajor', async () => {
+      setNodeVersionMajor(18);
+      const warnings = await getUserStartupWarnings('');
+      expect(warnings).toHaveLength(1);
+      expect(warnings[0]).toContain('Node.js');
+      expect(warnings[0]).toContain('requires Node.js 20 or higher');
+    });
+
+    it('should not return a warning if Node.js version is equal to minMajor', async () => {
+      setNodeVersionMajor(20);
+      const warnings = await getUserStartupWarnings('');
+      expect(warnings).toEqual([]);
+    });
+
+    it('should not return a warning if Node.js version is greater than minMajor', async () => {
+      setNodeVersionMajor(22);
+      const warnings = await getUserStartupWarnings('');
+      expect(warnings).toEqual([]);
+    });
+
+    it('should use default minMajor=20 if not provided', async () => {
+      setNodeVersionMajor(18);
+      const warnings = await getUserStartupWarnings('');
+      expect(warnings).toHaveLength(1);
+      expect(warnings[0]).toContain('Node.js');
+      expect(warnings[0]).toContain('requires Node.js 20 or higher');
+    });
+  });
+
   // // Example of how to add a new check:
   // describe('node version check', () => {
   //   // Tests for node version check would go here

packages/cli/src/utils/userStartupWarnings.ts

@@ -6,6 +6,7 @@
 
 import fs from 'fs/promises';
 import * as os from 'os';
+import semver from 'semver';
 
 type WarningCheck = {
   id: string;
@@ -32,8 +33,23 @@ const homeDirectoryCheck: WarningCheck = {
   },
 };
 
+const nodeVersionCheck: WarningCheck = {
+  id: 'node-version',
+  check: async (_workspaceRoot: string) => {
+    const minMajor = 20;
+    const major = semver.major(process.versions.node);
+    if (major < minMajor) {
+      return `You are using Node.js v${process.versions.node}. Gemini CLI requires Node.js ${minMajor} or higher for best results.`;
+    }
+    return null;
+  },
+};
+
 // All warning checks
-const WARNING_CHECKS: readonly WarningCheck[] = [homeDirectoryCheck];
+const WARNING_CHECKS: readonly WarningCheck[] = [
+  homeDirectoryCheck,
+  nodeVersionCheck,
+];
 
 export async function getUserStartupWarnings(
   workspaceRoot: string,