Fix a pod install error "undefined method 'exist' for File:Class" React Native

It is advised to use Brew to install the arm version of cocoapods for Apple M1/M2 chips.

brew install cocoapods
pod install # fail: "undefined method 'exist' for File:Class"

In Ruby 3.2, "Fill.exists" was removed. brew will automatically install the most recent version of Ruby when you perform a brew install cocoapods, which is why you encounter this problem.

There are two fixes I found—the first is advised by the React Native team, and the second is really quick but ugly!

---

1. Make use of a Ruby version manager

1.1) In the root of your react native project, create a .ruby-version and Gemfile

.ruby-version:

2.7.8

Gemfile:

source 'https://rubygems.org'

# You may use http://rbenv.org/ or https://rvm.io/ to install and use this version
ruby File.read(File.join(__dir__, '.ruby-version')).strip

gem 'cocoapods', '~> 1.13.0'

1.2) Install the Ruby version manager

brew install rbenv ruby-build # install ruby ver. manager
rbenv init                    # load rbenv in your shell
# ^^^follow instructions after re-run terminal!!! 
rbenv install 2.7.8           # install required Ruby version

1.3) Preinstalling ruby gems

cd your/rn_project/folder
rbenv local     # switch to 2.7.8 ruby version
bundler install # install gem deps

Finally, execute the following command to install pods when necessary

cd ios; bundler exec pod install
# or
bundler exec pod install --project-directory=ios

---

1. Hacky/Dirty way: Install cocoapods using an outdated version of Ruby:

# clean up
brew uninstall --ignore-dependencies ruby --force
brew uninstall cocoapods --force
sudo gem uninstall cocoapods

# install cocoapods 
brew install ruby@3.1
brew install cocoapods --ignore-dependencies
ln -s /opt/homebrew/opt/ruby@3.1 /opt/homebrew/opt/ruby

Comments

[NIYODUSENGA Clement]

You saved my day. Gracias

[Eduardo Mazzucco Cividini]

Life saver, thank you so much!

[Ahmed Hassanein]

"There are two fixes I found—the first is really quick but ugly, and the second is advised by the React Native team!"
I think the order is reversed, right? :D

[Davyd NRB]

yes)

[Johan Tibell]

Could you post a link to the React Native team recommendation?

[Davyd NRB]

sure
reactnative.dev/docs/environment-s...

[Mykyta]

Thanks a lot!
Spent half my day trying to get the project up and running on the new M2 Pro until I stumbled upon this article.