Package manager mismatch on EAS Build

[M-Farih]

Hello everyone,
I am getting below error on my eas build,
Install dependencies Logs:
Running "yarn install" in /Users/expo/workingdir/build directory
This project is configured to use pnpm because /Users/expo/workingdir/build/package.json has a "packageManager" field
yarn install exited with non-zero code: 1

[hamzamekk]

can you share with us the steps you did that leads you to this error ?

[M-Farih]

This is my project setup:
eas.json
package.json

In my app.config.ts, I also added the following configuration for updates and caching, as recommended by EAS to continue building:
updates: {
url: 'https://u.expo.dev/8bbbfa28-cfdb-43a6-b8ae-be20608b2e8f',
fallbackToCacheTimeout: 0,
},
runtimeVersion: {
policy: 'appVersion',
},

I previously published my app to the App Store using Yarn and an older SDK. Now, I’ve migrated to SDK 52 using your latest template and implemented all the necessary updates. My project now matches your current template exactly, with no changes missed.

Environment info:
System:
OS: macOS 15.4.1
Shell: 5.9 - /bin/zsh
Binaries:
Node: 22.15.0 - ~/.nvm/versions/node/v22.15.0/bin/node
npm: 10.9.2 - ~/.nvm/versions/node/v22.15.0/bin/npm
Watchman: 2024.05.06.00 - /usr/local/bin/watchman
Managers:
CocoaPods: 1.15.2 - /usr/local/bin/pod
SDKs:
iOS SDK:
Platforms: DriverKit 24.4, iOS 18.4, macOS 15.4, tvOS 18.4, visionOS 2.4, watchOS 11.4
IDEs:
Android Studio: 2023.1 AI-231.9392.1.2311.11076708
Xcode: 16.3/16E140 - /usr/bin/xcodebuild
npmPackages:
expo: ~52.0.46 => 52.0.46
expo-router: ~4.0.20 => 4.0.21
expo-updates: ~0.27.4 => 0.27.4
react: 18.3.1 => 18.3.1
react-dom: 18.3.1 => 18.3.1
react-native: 0.76.9 => 0.76.9
react-native-web: ~0.19.13 => 0.19.13
npmGlobalPackages:
eas-cli: 16.4.1
expo-cli: 6.3.12
Expo Workflow: bare

[M-Farih]

🚨 [EAS Build Tip for pnpm users]
I ran into a frustrating issue where EAS Build was trying to run yarn install even though my project uses pnpm, causing the build to fail.

📌 Root cause:
I had accidentally git-ignored pnpm-lock.yaml, so EAS couldn’t detect that my project uses pnpm. It defaulted to Yarn and failed with this error:

This project is configured to use pnpm because package.json has a "packageManager" field
yarn install exited with non-zero code: 1

✅ Fix:
Make sure pnpm-lock.yaml is committed to your repo. EAS Build uses it to correctly choose the package manager.
Hope this saves someone else hours of debugging!