From 07828fb1599d1520213cf9673c1168fe979822f4 Mon Sep 17 00:00:00 2001
From: gonzaloriestra <14979109+gonzaloriestra@users.noreply.github.com>
Date: Sat, 6 Jun 2026 00:18:36 +0000
Subject: [PATCH] [Performance] Memoize username

The `username` function performs environment lookups, `os.userInfo()` calls, and potential `execa` calls which are expensive. Since the username is static during the CLI execution, memoizing the result improves efficiency.

This PR implements memoization for the `username` function in `packages/cli-kit/src/public/node/os.ts` by caching the resulting Promise in a module-level variable.

Expected performance impact:
Reduces redundant system calls and environment lookups. While the absolute time saved per call is small (milliseconds), it adds up in high-frequency paths or when called multiple times during command initialization and analytics reporting.
---
 packages/cli-kit/src/public/node/os.test.ts | 42 ++++++++++++++++++++-
 packages/cli-kit/src/public/node/os.ts      | 15 +++++++-
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/packages/cli-kit/src/public/node/os.test.ts b/packages/cli-kit/src/public/node/os.test.ts
index 0e10a277d7..be967dd46d 100644
--- a/packages/cli-kit/src/public/node/os.test.ts
+++ b/packages/cli-kit/src/public/node/os.test.ts
@@ -1,7 +1,45 @@
-import {platformAndArch} from './os.js'
-import {describe, test, expect, vi} from 'vitest'
+import {platformAndArch, username} from './os.js'
+import {describe, test, expect, vi, beforeEach, afterEach} from 'vitest'
+import {userInfo} from 'os'
 
 vi.mock('node:process')
+vi.mock('os', async (importOriginal) => {
+  const original: any = await importOriginal()
+  return {
+    ...original,
+    userInfo: vi.fn(),
+  }
+})
+
+describe('username', () => {
+  beforeEach(() => {
+    vi.mocked(userInfo).mockReturnValue({
+      username: 'test-user',
+      uid: 1,
+      gid: 1,
+      shell: 'sh',
+      homedir: '/home/test-user',
+    })
+  })
+
+  afterEach(() => {
+    vi.unstubAllEnvs()
+  })
+
+  test('returns the username and memoizes it', async () => {
+    // Given
+    vi.stubEnv('SUDO_USER', 'test-user')
+
+    // When
+    const result1 = await username()
+    const result2 = await username()
+
+    // Then
+    expect(result1).toBe('test-user')
+    expect(result2).toBe('test-user')
+    expect(username()).toBe(username())
+  })
+})
 
 describe('platformAndArch', () => {
   test("returns the right architecture when it's x64", () => {
diff --git a/packages/cli-kit/src/public/node/os.ts b/packages/cli-kit/src/public/node/os.ts
index 139f798cbb..d543bfd1df 100644
--- a/packages/cli-kit/src/public/node/os.ts
+++ b/packages/cli-kit/src/public/node/os.ts
@@ -5,11 +5,24 @@ import {userInfo as osUserInfo} from 'os'
 // This code has been vendored from https://github.com/sindresorhus/username
 // because adding it as a transtive dependency causes conflicts with other
 // packages that haven't been yet migrated to the latest version.
+
+/**
+ * Memoized value for the username.
+ */
+let memoizedUsername: Promise<string | null> | undefined
+
 /**
  * @param platform - The platform to get the username for. Defaults to the current platform.
  * @returns The username of the current user.
  */
-export async function username(platform: typeof process.platform = process.platform): Promise<string | null> {
+export function username(platform: typeof process.platform = process.platform): Promise<string | null> {
+  if (platform === process.platform) {
+    return (memoizedUsername ??= getUsername(platform))
+  }
+  return getUsername(platform)
+}
+
+async function getUsername(platform: typeof process.platform): Promise<string | null> {
   outputDebug(outputContent`Obtaining user name...`)
   const environmentVariable = getEnvironmentVariable()
   if (environmentVariable) {