nio4r | platform asynchronous I/O primitives for scalable network | Reactive Programming library

I'm not really sure what happened and why but I tried doing this on my rails container and I was no longer receiving the said error.

1. docker-compose run --rm bash
2. cd to project directory
3. bundle install

make: /usr/bin/mkdir: Command not found it's the reason.

Please write this command with sudo perm.

sudo ln -s $(which mkdir) /usr/bin/mkdir

And try again bundle.

From your ruby -v, I see that you are in an Intel x86 Mac, but the gem that your trying to build (nokogiri-1.11.3-arm64-darwin) is for new Mac ARM M1 chips. If this is the cause, it means your are using precompiled gems.

Try uninstalling the gem, specify that you don't want to use precompiled gems, and reinstall.

Gemfile.lock is a file generated from Gemfile. As such, instead of trying to merge the two branches, it's simpler and more accurate to generate a new one from its canonical source. This might result in slightly different versions, but these should cause no trouble; any version restrictions should be defined in your Gemfile.

Normally one does not commit generated files, they can change in trivial ways, but Gemfile.lock is a special case where you do want this to be the same for all builds.

Resolve any conflicts in the Gemfile. Regenerate Gemfile.lock. Add it.

for some reason he copied the code and added it himself

This is a good opportunity to explain to them why this is a bad practice when working with a team. It might be easy for them, but it's causing trouble for you. They might need instructing in how to update their work in progress. Or you might need to extract some changes into their own branch and get that merged.

You can disable this error with option -Wno-error=implicit-function-declaration

So try this

With the help of a friend I fixed this. It may have been caused by me downloading a gem via the command line and then adding it to my gemfile which caused a problem with my country_select gem's dependencies.

I tried many things to fix it, and I'm not sure what solved it, so here's what I did:

I deleted my gemfile.lock and ran bundle install and tried rails server again. This caused a different file to not be found. I tried deleting my gemfile.lock and running other commands: bundle update --all, bundle install --redownload, or bundle pristine. Each time, rails server wouldn't start the server because it 'could not find nio4r-2.5.4 in any of the sources'.

Finally, I tried running "bundle exec rails server" and it started the server. However, my "rails test" command was still broken. I think I will need to add "bundle exec" before my rails commands for things to keep working. This may be the only thing that fixed it.

gem install installs a gem on your computer. If you want to include a gem in your rails app, you need to add it to the gemfile:

Solved by following the steps at https://stackoverflow.com/a/48312139/13217139 then re-installed the gem with gem install ffi -- --enable-system-libffi

Its likely because of not having your default ruby-version defined, Try these: