Why does a Ruby version update require installing bundler? - ruby-on-rails

My application was running fine with Ruby 2.2.4, until running a test gave me an error saying "the ruby version you're using is outdated/buggy".
So I updated and used Ruby 2.3.0 as the default for my application. After that I got an error saying "could not find bundler".
I already had bundler, so why does updating the Ruby version require reinstalling bundler into my application?
(I am learning Ruby-on-Rails, so treat me as a beginner.)

Each copy of Ruby installed on a computer has its own set of installed gems. One reason that gems aren't shared between installations of Ruby is that some gems include compiled native code, and the compiled output might be different for different versions of Ruby.
bundler is a standalone gem, not part of Ruby, so whenever you install a new Ruby you have to install bundler in that Ruby.
This is independent of whether you're using a Ruby version manager (chruby, rbenv, rvm, etc.); if you install a new Ruby, it needs its own set of installed gems.

Whenever you install a new version of Ruby with RVM it creates a wrapper with what they call gemsets. Gemsets are not shared between ruby version so therefore when you installed your new Ruby 2.3.0 it installed without any gems.
To fix this problem simply install bundler by running gem install bundler.
Once that's done, you should have it available for your new installation of Ruby.

I also had faced such issue. First I run this with selected RVM version.
gem install bundle
Then you should run:
bundle install
In your project directory.
Please let me know if you have any confusion.

Related

Rails bundler is not finding correct Ruby version in OSX Catalina

I've recently upgraded to OSX Catalina and when I try to do
bundle install
on the Rails project, I get an error:
Cannot bundle the project, current system is on Ruby 2.6.3 and gemfile
specified Ruby 2.4.2.
What's bizarre is that the Catalina system is a fresh install and I used rbenv to do a single install of Ruby version 2.4.2. In fact, if I run
ruby -v
It comes back with ruby version 2.4.2 as the only ruby version installed (and the default).
I'm totally stumped, has anyone else seen this behaviour or have any idea of how I can resolve this?
So I finally solved this, although I'm a little mystified as to the cause/solution.
Basically, I uninstalled the bundler gem and installed the one the project had in it's Gemfile (1.16.2)
For whatever reason, I'm not sure how bundler got installed on the fresh machine, I suspect maybe through RVM or Rbenv, but with that version of bundler it was somehow assuming that I had Ruby 2.6.3 installed, even though it didn't appear as a version on my machine.

Running old Ruby versioned app on newer version of Ruby

Is it possible to run a Ruby application that was developed in Ruby 2.1.2 on a machine that has Ruby 2.1.5 installed? I'm new to Ruby and I'm starting to think that's not possible. A newer version of Ruby cannot run an older one? Can someone confirm?
When I type "rails server" I get the error message saying "You ruby version is 2.1.5, but your Gemfile specified 2.1.2 (Bundler::RubyVersionMismatch)". One of the messages it gives me is "ruby-2.1.2 is not installed". And then it says "To install do: rvm install ruby 2-1-2"
I tried commenting out the ruby version in Gemfile and/or changing the version number but I get more error messages now:
Juste remove/comment your version of ruby specified in Gemfile like this
#ruby '2.1.2'
Or install ruby '2.1.2' with RVM (Ruby Version Manager) on your environment:
RVM
In terms of recent history, the biggest shift in the Ruby language was between Ruby 1.8 and Ruby 1.9 where a number of things caused conflict due to changes in syntax and enforcing UTF-8 encoding.
Ruby 2.0 and 2.1 introduce more features but don't really impact backwards compatibility. It's very rare that a shift from 2.1.2 to 2.1.5 would cause problems with one exception:
You will probably need to reinstall all your bundled gems.
Normally this is done with:
bundle install
Note that Bundler itself is a gem, so you may need to install that if the bundle command is not available for that version of Ruby:
gem install bundler
If you're having a conflict due to mismatched Ruby versions in your Gemfile, edit that file to reflect your desired version.
Many multi-version Ruby managers like RVM and RBenv use a .ruby-version file in the main application directory to specify this instead. This is a gentler approach than locking down your Ruby version in the Gemfile itself.
If you need to install a new version of Ruby on your server:
rvm install 2.1.5
rvm --default 2.1.5
rvm use 2.1.5
gem install bundler
bundle install
That should make it available.

I am having trouble uninstalling Rails 4.1.5 and installing Rails 4.0.8

I tried uninstalling Rails 4.1.5 by doing "gem uninstall rails" and then installing Rails 4.0.8 by doing "gem install rails --version 4.0.8". However, now when I try to see what version of Rails I am using by doing "rails -v" I still get "Rails 4.1.5". How do I fix this?
I know I'm a bit late however I am answering in case others need an answer of how to manage gem versions. The linked duplicate question offers a perfectly fine answer to the question but does not give guidance to how to easily manage this long term. I do the following before starting every new project.
First you need rvm to manage ruby versions and create gemsets. With gemsets you can create isolated groups of gems that are project or ruby or rails version specific (it's up to you how you organize yourself).
After installing a version of ruby to use you create a gemset and tell your system to use this version of ruby with this gemset.
Then select the gemset and install the version of rails you want to use into the gemset. You will also need to install bundler into the gemset.
Once you have this setup you can insert the following lines into your rails gem file to tell this project which ruby version, rails version and gemset to use (in my example I am using ruby version 2.1.5 with the gemset named scan and the rails version 4.0.8)
ruby '2.1.5'
#ruby-gemset=scan
gem 'rails', '4.0.8'
Then cd into the rails project directory and run bundle install. Bundler will install the gems from your project's gem file into the selected gemset. Now you have an isolated and stable system for the project. If you have another project with different ruby version, rails version and gemset any changes there will not affect anything here.
For more details on how to setup rvm just go to the website and read the documentation. It's really easy to use and will save you many headaches.

How do I upgrade the Ruby version of my project?

I recently started learning Rails using Ruby 1.9.3p385, and I'm trying to develop a small project with it.
I'm using Linux so I installed Ruby using RVM.
I developed a few pages, following some tutorials. I would like to upgrade my project to use Ruby 2.0.0. What do I have to do?
I installed Ruby 2.0.0 with RVM:
rvm install 2.0.0
Everything seems OK, so I tried to use it:
rvm use 2.0.0-p247
But when I try to run my Rails server using rails server, I get the following message:
bash: rails : command not found
I've read the RVM documentation about upgrading Ruby but I don't really understand what it does; I'm afraid of breaking everything.
Does it will upgrade my project in a way it will use Ruby 2.0.0 or what should I do?
Next, I will want to upgrade also to Rails v4.
Your gemset which comes with new Ruby version is empty. Try this:
gem install bundler # this will install bundler
bundle # this will use bundler to install required gems
rails server
Did you run rvm use 2.0.0-p247 or did you use rvm use 2.0.0-p247 --default? The later will set Ruby v.2.0 as the default for your system. Failure to do that will revert your Ruby to whatever RVM's default is the next time you log into your system or open a new terminal window.
When RVM installs a new version of Ruby, it installs only the default gems. It CAN upgrade a Ruby to another version, and optionally install the existing gems as it does so, but that's not what you asked it to do: rvm install 2.0.0 only installs Ruby. At that point you have to install the other gems you need, which would include Rails.
My general practice when installing various versions of Ruby and the gems I like is to use two command-line pipes to dump my existing gems, then (re)install them. First I switch to an existing Ruby whose gems I want to duplicate, then run:
gem list | cut -f1 -d' ' > ~/gem_list
Then I switch to the newly installed one, and run this:
xargs gem install < ~/gem_list
This does a completely clean install of the gems, outside of RVM's commands.
Why? Habit. Paranoia based on some "experiences" I had in the past with RVM.
Once that's all done and I have brand-spanking-new Ruby and gems, I'll proceed with running bundler or other housekeeping chores.
when you install a new ruby version, you have to reinstall all the gems for that version. start of by installing bundler first. Then run bundle in your rails root directory. When you encounter no errors, you're good to start the rails server. Good luck!
run bundle install on the application root, you need to reinstall all your dependencies for the new version of Ruby.

How to fix gems that stopped working after installing RVM on Mac OS 10.7.5

In order to get Rails running correctly on my mac I used this site: http://railsinstaller.org/mac
Which worked great! - RVM is installed and the latest version of Ruby. Unfortunately, I used to use a gem called compass and now it crashes after the new install of RVM.
Is there a way I can just uninstall the old ruby gems I had on Ruby 1.8.7 and reinstall them using the new version of Ruby 1.9.3 I have installed?
when I type gem uninstall compass it says I don't have it installed. How do I run the gem command from the old version of Ruby? (I'll have to do this for compass and susy and the like)
In fact - can I get a list of all previously installed gems and uninstall all of them?
Use rvm use system to change back to the system RVM and gems to uninstall things and list them (gem list).
After listing them, you can go install them in the 1.9.3 environment (via normal gem install, perhaps with a long list of the gems from the system set)

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