Rails 6.1.7.10 Update Triggers uninitialized constant ActiveSupport::LoggerThreadSafeLevel::Logger (NameError)

The concurrent-ruby version updated, that has a dependency with active support gem.

concurrent-ruby's 1.3.5 version just released few hours ago, but I think there is an issue on it.

Downgrading the concurrent-ruby's version to 1.3.4 in the gemfile will fix this.

concurrent-ruby v1.3.5 has removed the dependency on logger

https://github.com/ruby-concurrency/concurrent-ruby/commit/d7ce956dacd0b772273d39b8ed31a30cff7ecf38

Just block the gem into your gemfile to the previous version

RUBYCopied
gem 'concurrent-ruby', '1.3.4'  

or update rails to 7.1, all Rails versions before are affected by this issue because they have a direct dependency on concurrent

https://github.com/rails/rails/issues/54260

Many of the answers have suggested pinning concurrent_ruby to 1.3.4, but I believe that's misunderstanding the problem. There's no problem in concurrent-ruby, this issue is actually in ActiveSupport 6 (and maybe 7.0), and concurrent-ruby version prior to 1.3.5 masked the issue.

The issue in Rails was fixed in commit 0f5e7a66143.

The solution is to add require "logger" (note that logger is a core Ruby library) to your application/gem/test file prior to loading Rails (or ActiveSupport).

For me (MacOs Ventura 13.1) Adzap's answer worked but without the require "bootsnap/setup" since that wouldn't run.
Simply adding require "logger" to config/boot.rb did the trick.

you need to update/downgrade ruby please follow these instructions as i had the same issue and fixed by this one

https://dev.to/luizgadao/easy-way-to-change-ruby-version-in-mac-m1-m2-and-m3-16hl

I’ve found a temporary workaround: add require "logger" before require "rails" at config/application.rb.

However, I believe that locking the version of concurrent-ruby is also a solution.

I have fixed the issue by doing the following in my project directory:

1. /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

2. echo >> /Users/zainishfaq/.zprofile

3. echo 'eval "$(/opt/homebrew/bin/brew shellenv)"' >> /Users/zainishfaq/.zprofile eval "$(/opt/homebrew/bin/brew shellenv)"

4. open .zshrc

5. Add the following in the zshrc file

   BASHCopied
   export PATH=$HOME/development/flutter/bin:$PATH
   export PATH=$HOME/.gem/bin:$PATH
   # Add RVM to PATH for scripting. Make sure this is the last PATH variable change.
   export PATH="$PATH:$HOME/.rvm/bin"
   export PATH="/opt/homebrew/bin:$PATH"
   

6. rvm get stable

7. rvm install 3.1.2

If anyone arrives here and is uncomfortable with locking the concurrent-ruby version, you can require logger and leave concurrent-ruby version unlocked. This is primarily an issue for older Rails 7.0 and 6.1.

In config/boot.rb

RUBYCopied
require "bundler/setup" # Set up gems listed in the Gemfile.
require "logger" # Fix concurrent-ruby removing logger dependency which Rails itself does not have
require "bootsnap/setup" # Speed up boot time by caching expensive operations.

This appears to have broken the cocoapods integration in our iOS project. As above, running

bundle add concurrent-ruby -v 1.3.4

in the project root resolved the issue.

This might cause issues down the road as cocoapods updates so keep an eye on that and remove this line if/ when that happens.